PDA

View Full Version : Attic Problems moisture.....



Michael
02-19-2008, 05:22 AM
hello

My house was built in 2001, it is a two story colonial the roof has arcuteture shingles on it. My attic has at least 12 inches of blown in insulation in it, 6 inches of fiberglass blown in and 6inches of cellulose on top of that. My attic is being vented by soffit vents(with the pink P vents that run up along the roof from the roof line), two 18 x 24 Gable end vents and a ridge vent running across the top of the roof. All of these vents are open, the ridge vent and the gable vents are new installs.

The humidity in the house has been between 35 and 40%. However the humidity in the attic has been 65 to as high as 98%. The tempature in the attic is the same as the tempature outside, within 5 degrees or so. I don't think I have much heat lose from the house because the snow doesn't melt quickly.

Yesterday the tempature reached 50 degrees here in New hampshire and it was raining. The snow covered roof was melting and I went up in the attic and noticed that the sheathing had become very wet and droplets had form on the nails. This is not the first time.

I am at the end, I have had restoration guys and insulation guys here, trying to fix the problem. The restoration guys had me spend $1700 on the gable vents, the ridge vent and to re-route the bathroom exhuaust fan from in the soffit to out the gable end wall. The insulation guy states that there is no problem with the insulation (thought maybe the blown in stuff was holding in the moisture creating condensation). Today the restoration guys are coming to check to see it there is water under the shingles on top of the sheathing from the outside.
If anyone knows of anything I can do, I am very frustrated and I am scheduled to deploy to Iraq soon and don't want to leave this for my wife to worry about. Here are some pictures of the roof and the attic.

thank you
Michael

Raymond Wand
02-19-2008, 06:05 AM
It could be melt water backing up under the shingles. If the attic is adequately vented it should not be this wet in my opinion and only in certain secitons. I would also be inclined to seal any penetrations into the attic such as waste vents, exhaust fans, ceiling light boxes to prevent warm moist air entering into the attic and condensing on cold decking.

Jerry Peck
02-19-2008, 07:06 AM
Michael,

Go here, Building Science Corporation - Technical Resources (http://www.buildingscienceconsulting.com/resources/default.htm) , click on the 'Contact Us' link at the bottom of the page after reviewing the information on that site.

I suspect that, as Aaron said on the other thread with this same post, the end result will be an unvented attic with insulation moved to the bottom of the roof sheathing, removing the insulation installed on the ceiling (Dr. Joe L. may say that can stay, maybe not), making the attic 'semi-conditioned space', or, even adding a vent or two to the attic space making it 'conditioned space'.

Dr. Joe is the one most of us learn from.

Review his web pages, you will find lots of excellent applicable information, including this: http://www.buildingscienceconsulting.com/resources/roofs/Unvented_Roofs_Assemblies_for_All_Climates.pdf

Aaron Miller
02-19-2008, 07:17 AM
East Coast Jerry is correct. Lstiburek has been researching this for a very long time and has the ear of everyone from the DOE on down (or up depending on your perspective).

Addition of at least one supply duct (with no return duct) promotes positive pressure in the attic space.

Someone else on the other thread of this same post suggested that sealing the interstitial cavities between joists with foam is a bad idea because it masks roof leaks. I'd like to address this, what I consider to be, wrong thinking. It presupposes a leaking roof. Though most (perhaps all) roofs will leak under the right circumstances, a properly installed roof will leak under only catastrophic conditions which cannot be prevented by construction techniques.

Even in the event of a leak, use of up-to-date decking, underlayment and roofing materials, should minimize if not totally eliminate any possibility of deterioration.

Of course, if your roof is being built in Texas by roofers from south of the Texas border, regardless what you use will not work as intended.

Aaron:D

Raymond Wand
02-19-2008, 07:28 AM
Aaron

I was involved with a cottage in northern Ontario. Spray foam applied to underside of roof deck. Less than 5 years old construction (high quality construction). The roof leaked, it was leaking for some time before the leak became evident. The drywall and foam were removed in the vicinity of the leak it was a mess. Decking replacement, drywall replacement... No one could locate the leak, in the end the shingles were ripped off and replaced. Ouch.

Now another small leak has developed and its going to be a bugger to find it, I guess IR scan would be helpful?

Cheers,

Dom D'Agostino
02-19-2008, 07:35 AM
I would also be inclined to seal any penetrations into the attic such as waste vents, exhaust fans, ceiling light boxes to prevent warm moist air entering into the attic and condensing on cold decking.


This is often overlooked, but your attic has too much humidity (you stated as high as 98%) and it's coming from somewhere.

Richard Stanley
02-19-2008, 07:46 AM
I agree - contact Joe.
I wonder - Is it possible to have too much insulation? Kind of like wearing too many clothes in the winter time - you sweat.

Jeff Remas
02-19-2008, 08:00 AM
Are you burning any ventless appliances in the house like a ventless propane wall heater or ventless gas logs?

For a good explanation of what is needed, go to this link:

REMAS Home Inspections, Inc. - Serving all of Northeastern Pennsylvania (http://www.remasinspections.com/Attic.html)

Some times the wrong brand ridge vent (they are most definitely not all the same) or bad soffit vents (are there enough, are they painted over, not enough "free air"rating)

Aaron Miller
02-19-2008, 08:16 AM
Raymond:

I can't speak to your example house, I was not there. I can say that, if a roof is properly constructed of modern materials it will not leak except under exigent circumstances which cannot be prevented by flawless application of perfect materials.

Even if you don't want to step into the 21st century and utilize materials such as borate pressure-treated framing and sheathing, self adhesive butyl underlayment and high-end shingles, you can still do better than the typical cheap shingles over 15lb. felt, 7/16" OSB sheathing, and finger-joint SPF framing. Even OSB can be purchased with zinc borate treatment. For that matter CDW plywood with CCA or ACZA treatments are decent choices.

If a builder really wants to construct a house that produces the model code-required weather-resistant envelope that prevents the accumulation of moisture within the roof or wall assemblies, it can be done; just not the way most houses are slapped together nowadays.

Maybe we should send our roofers back to the country of their origin and do it ourselves.

Aaron:D

Jim Luttrall
02-19-2008, 10:16 AM
Hi Michael, I know time is not on your side, but it MAY just be a weather anomaly that will pass once the weather changes. IF the outside humidity is near 100% as it is when it is raining and the air is drawn into the attic through the soffit vents and then hits the bottom of the colder roof decking (snow still on top) then the moisture will condense out onto the roof. A few degrees colder or warmer on the outdoor temperature and this won't happen.
The bad new is there is nothing I know of that you can do to prevent this short of a attic redesign. The good news is it will clear up on its own with little or no damage. Once the roof deck warms above the dew point of the ambient air, moisture will not condense out on the surfaces.

I would check again for any air leaks through the ceiling, but from the amount and placement of snow on the roof I doubt this is still an issue.

BTW, thanks for your service.

Aaron Miller
02-19-2008, 10:30 AM
Michael:

At the risk of repeating myself and others - seal off the attic. Ventilated attics and crawl spaces are antiquated ideas that date back more than a couple of centuries. The 21st century awaits you. . .

Aaron:D

Raymond Wand
02-19-2008, 11:29 AM
Btw is there a vapour barrier installed on the attic floor under the insulation?

Jerry Peck
02-19-2008, 02:56 PM
Hi Michael, I know time is not on your side, but it MAY just be a weather anomaly that will pass once the weather changes. IF the outside humidity is near 100% as it is when it is raining and the air is drawn into the attic through the soffit vents and then hits the bottom of the colder roof decking (snow still on top) then the moisture will condense out onto the roof. A few degrees colder or warmer on the outdoor temperature and this won't happen.

... until a similar weather anomaly reoccurs - that is, assuming it is a "weather anomaly".


The bad new is there is nothing I know of that you can do to prevent this short of a attic redesign.

Well, if one *wants* to stick to the old ventilated attic when they are having problems related to that attic design, then they would need to make sure the ventilation was uninhibited, i.e., install powered ventilation. Of course, though, once that is done, then an entirely different set of problems occur as: a) if the powered ventilation is 'blowing air into the attic', which pressurizes the attic, forcing the outside air into the home's interior below; or b) if the powered ventilation is 'sucking air out of the attic', which de-pressurizes the attic, forcing the air inside the home's interior to be sucked up into the attic above. Neither one will provide good results and both create a total waste of energy to power the ventilation fan and to condition replacement air inside the home.

In case I was not clear on the above - neither pressurizing nor de-pressurizing the attic is a good idea.


The good news is it will clear up on its own with little or no damage. Once the roof deck warms above the dew point of the ambient air, moisture will not condense out on the surfaces.

And it comes back again because the source of the problem has not been identified and corrected.

Or, as Aaron said "At the risk of repeating myself and others - seal off the attic. Ventilated attics and crawl spaces are antiquated ideas that date back more than a couple of centuries.", but don't take our word for it, visit the Dr. Joe's website and review the information for yourself.

With time being of importance, I would contact Dr. Joe through his web site. They know more about this than we do, which is why they teach us and we learn from them.

Roger Hankey
02-19-2008, 03:54 PM
1. I agree that Dr. Joe Lstribrick is one of the most knowledgeable on the topic.
2. What you write and the photos you show indicate to me that even though your house was built in the last 7 years, it may have not incorporated the best building practices. I suspect that there are air leaks from the house into the attic. I base this conclusion on the high level of indoor humidity you report, AND the rust spot around most of the roofing nails penetrating the plywood roof sheathing.
3. I encourage you to attempt to determine if attic bypasses (air leaks from the house to the attic) were sealed. Typical bypasses are at the plumbing vents (round pipes in square holes at the top of the walls) and wiring penetrations (holes larger than the cables that pass through them.
If you have ever seen FROST in the attic in extreme cold weather, then the presence of bypasses is certain. You can check for the bypass locations this very carefully walking on the ceiling joists and kneel on a board near the plumbing vent. Move back the insulation around the vent and see if there are gaps around the pipe. If so, you will need to seal the pipe and wire penetrations with expanding foam caulk.
4. For more help in your area contact an energy auditor who does "blower door and IR scan" home performance tests. Once they test the house they can quantify the air leaks, identify their location and recommend qualified insulation contractors to help you.
Best wishes

Kevin Barre
02-19-2008, 04:50 PM
Michael--
I suspect a couple of problems. First, the bath exhaust vents should NOT exit out the gable end wall. Think about it...if you have gable vents, couldn't that moisture get pulled right back in...especially if you also have ridge vents? The air will flow in from the point of least resistance to replace the warmer air exiting out the ridge...that means it could flow in thru the gable vents in your home. The bath vents should all exit out the roof. Also, you should not have both gable vents and ridge vents. In doing so, you will "short circuit" the ventilation. Air will be drawn in the gable louvers as it exits out the ridge vents. Without the gable vents, air would be pulled in thru the soffitt vents, ensuring full air changes. As is, you will not get full air change in the lower part of the attic, and moisture will build up. It's condensing on the colder surfaces in the attic. Lastly, it is still possible that you have some warmer, moister air leaking into the attic around ceiling penetrations. Nonetheless, I still think that a properly designed ventilation system would handle that. If you have enough inlet (soffitt vents) and enough ridge vents, you would be OK.
My recommendation would be to re-route the bath exhaust vents thru the roof. Then, close off the gable louvers and let the ridge vent do its job in tandem with a properly designed inlet vent system at the soffitt.

Jerry Peck
02-19-2008, 05:20 PM
Kevin,

Why re-route the bathroom exhaust discharge through the roof if you are then recommending to close off the gable vents anyway?

Based on my understanding of what you are saying, if you were to eliminate the gable vents for the ventilation condition of then venting soffit-to-ridge, there would not be any concern for the bath fan-venting-back-into-the-gable vent - the gable vent has already been closed off.

Am I missing something in what you are saying? :confused:

Kevin Barre
02-19-2008, 05:28 PM
Kevin,

Why re-route the bathroom exhaust discharge through the roof if you are then recommending to close off the gable vents anyway?

Based on my understanding of what you are saying, if you were to eliminate the gable vents for the ventilation condition of then venting soffit-to-ridge, there would not be any concern for the bath fan-venting-back-into-the-gable vent - the gable vent has already been closed off.

Am I missing something in what you are saying? :confused:

Jerry--
You are correct in assuming that the gable-exhaust of the bath fans would be a moot point IF the gable louvers are closed off. However, if they aren't, then routing the bath vent up thru the roof would still be beneficial.
My assumption is that the homeowner is likely to be confused by all this and try the one thing he hasn't already done anything about first, i.e., re-routing the vent. So even if he won't close off the gable vents (which he just paid to have installed) he might try re-routing the bath vents. After all, it's not particularly expensive and it's something no one else has told him to do yet.

EDIT: Just in case anyone misses my point, I believe there are two related problems: moisture and overall ventilation. Venting the bath fans thru the roof MAY solve the moisture issue IF there are no other large sources of moisture such as leaks around ceiling penetrations, particularly in bathrooms. However, if the gable vents are left in place, the overall ventilation pattern will still probably be poor. If this is the case, and IF there are leaks thru bath ceilings, then venting the fans out the roof won't be fully effective.

Mike Schulz
02-19-2008, 05:40 PM
I have seen this a couple of times. Both times was related to wet crawl spaces. Moisture passing through the home collecting on the roof sheathing in the winter. Warm days and cold nights can play havoc.

Is your ground wet allot around the home?
Is the crawl space dry?
Gutters downspouts drain away from home.
Do you have a sauna or hot tub in the home.
Take dozens of baths without the exhaust fans on.
Wife Boils allot of water.
Aquariums?

All these sound silly but could contribute allot.

Think of your home as a chimney.

I skimmed through the above so if someone posted something similar except my apology

Raymond Wand
02-19-2008, 05:42 PM
I think our guest should undertake to seal the floor of the attic and check other issues before he spends all that money having foam applied. Given that the house is not sealed properly anyway, and if the wetness is due to a myriad of things....

Michael
02-19-2008, 05:46 PM
Hello

Thank you for all your attention to this matter, the restoration guys came today and peeled back some shingles and to no surprises the tar paper and sheathing were dry.

To answer a few questions, I don't have a vapor barrior under the blown in insulation. The restoration guys came with a moisture reader this morning and the sheathing was very wet. A surprise was when he put the meter on top of the insulation it wasn't that wet but as he pushed it through the insulation to the sheetrock the meter went to its limit, it maxed out.

So I am not sure but it looks like the insulation is holding in a lot of moisture or it is so wet that it can't dry out. I sent my email to Dr. Joe I am about ready to suck out all the blown-in insulation and replace it with R-38 faced.

BTW I think the ventilation is working because tonight with the outside tempature reaching 40 and the humdity was around 66% all the sheathing has dried up some. The humidity level in the attic went from 98% this morning to 67% tonight.

Mike Schulz
02-19-2008, 05:50 PM
Get out of the attic. Think outside the box!
You can vent to the cows come home but you need to fix the source.
Instead of all the adding of vents I would of installed a attic fan but that's not nether here nor there. I don't think venting is the issue.

Raymond Wand
02-19-2008, 05:51 PM
If there is no vapour barrier under the insulation, then why not remove that insulation and spray the floor with foam? That way you would have the best and least costly remedy in my opinion.

Cheers.

Kevin Barre
02-19-2008, 05:56 PM
Hello

Thank you for all your attention to this matter, the restoration guys came today and peeled back some shingles and to no surprises the tar paper and sheathing were dry...


BTW I think the ventilation is working because tonight with the outside tempature reaching 40 and the humdity was around 66% all the sheathing has dried up some. The humidity level in the attic went from 98% this morning to 67% tonight.
Don't read too much into the slightly less saturated moisture levels tonight. After all, when do most occupants of your home take showers? Morning, right? If that's the case, the attic should dry out somewhat during the day if additional water isn't being introduced...even with poor ventilation

Michael
02-19-2008, 05:59 PM
I don't have any ventfree appliances, we don't take alot of shower between 2 people.

Roger what is a "blower door and IR scan" and where can I found one?

Is your ground wet allot around the home? In the spring yes, not so much in fall or winter or summer, water drains pretty well pass my house.
Is the crawl space dry? My full basement is dry 40% humidity in winter and I run a dehumidifier in the summer.

Gutters downspouts drain away from home. No gutters

Do you have a sauna or hot tub in the home. No

Take dozens of baths without the exhaust fans on. No

Wife Boils allot of water. No

Aquariums? Yes but it is on the first floor with insulation between the floors for sound proof.

Michael
02-19-2008, 06:02 PM
If there is no vapour barrier under the insulation, then why not remove that insulation and spray the floor with foam? That way you would have the best and least costly remedy in my opinion.

Cheers.

My neighbor to the left of me has R30 faced in his attic and is bone dry...

Michael
02-19-2008, 06:12 PM
Michael--
I suspect a couple of problems. First, the bath exhaust vents should NOT exit out the gable end wall. Think about it...if you have gable vents, couldn't that moisture get pulled right back in...especially if you also have ridge vents? The air will flow in from the point of least resistance to replace the warmer air exiting out the ridge...that means it could flow in thru the gable vents in your home. The bath vents should all exit out the roof. Also, you should not have both gable vents and ridge vents. In doing so, you will "short circuit" the ventilation. Air will be drawn in the gable louvers as it exits out the ridge vents. Without the gable vents, air would be pulled in thru the soffitt vents, ensuring full air changes. As is, you will not get full air change in the lower part of the attic, and moisture will build up. It's condensing on the colder surfaces in the attic. Lastly, it is still possible that you have some warmer, moister air leaking into the attic around ceiling penetrations. Nonetheless, I still think that a properly designed ventilation system would handle that. If you have enough inlet (soffitt vents) and enough ridge vents, you would be OK.
My recommendation would be to re-route the bath exhaust vents thru the roof. Then, close off the gable louvers and let the ridge vent do its job in tandem with a properly designed inlet vent system at the soffitt.

Kevin what do you mean properly designed inlet vent system? Also what happens when snow block the ridge vent, it was told to me that the gable vents would help out in this matter. In this picture look at where the bathroom vent is in relation to the gable vent, do you think that the moist air blowing out of the bathroom vent will be moist enough to be a problem by the time it passes by or in the gable vent?

Michael
02-19-2008, 06:17 PM
Get out of the attic. Think outside the box!
You can vent to the cows come home but you need to fix the source.
Instead of all the adding of vents I would of installed a attic fan but that's not nether here nor there. I don't think venting is the issue.

Mike I had a gable fan up there, it was to cool things down in the summer. The fan had a humdity sensor on it, this fall, when the tempature started to drop the fan was turning on in the middle of the night. Not only was it noisy but it didn't help it just continued to run all night until early morning. That was how I found the moisture problem in the first place.

Jerry Peck
02-19-2008, 07:02 PM
My attic has at least 12 inches of blown in insulation in it, 6 inches of fiberglass blown in and 6inches of cellulose on top of that.

As a side note, loose fill (blown) fiber glass insulation loses maybe around 50% of its insulating R-value during cold temperatures. The cold air settles back down into and through the loose fill insulation, reducing its effectiveness.

That could allow the dew point (the temperature at which the moisture in the air condenses into water) to form under or in the cellulose insulation. Cellulose insulation is, after all, basically shredded paper with a fire retardant chemical, and cellulose (paper) gets wet and holds water.


To answer a few questions, I don't have a vapor barrior under the blown in insulation.

I sent my email to Dr. Joe I am about ready to suck out all the blown-in insulation and replace it with R-38 faced.

The facing on the fiberglass batt insulation is a vapor retarder, not a vapor barrier, however, if it retards (reduces) a sufficient amount of water vapor (moisture) from going into the attic, the balance between temperature and relative humidity changes, which changes the dew point. This might allow things to not condense water, and, once condensation occurs, it might allow things to dry out.

Before doing anything, wait for Dr. Joe's response.

Kevin Barre
02-19-2008, 07:26 PM
Kevin what do you mean properly designed inlet vent system? Also what happens when snow block the ridge vent, it was told to me that the gable vents would help out in this matter. In this picture look at where the bathroom vent is in relation to the gable vent, do you think that the moist air blowing out of the bathroom vent will be moist enough to be a problem by the time it passes by or in the gable vent?
Michael--
I see no snow blocking the ridge vents in your photo.

By properly designed inlet vents, I mean that you need an adequate amount of inlet vents to handle the airflow out the top side. Also, there should be an unobstructed flow from the soffitt into the attic. That's what the pink baffles you referred to are for. They need to be adequate in number and not blocked off in any way. Keep in mind that this is difficult to diagnose just based on what info you post. A site visit from someone who is local and who understands the issues would be beneficial.

The air flowing out the bath vent appears to be a good distance away from the gable inlet. However, warm air rises, and, depending on the direction of the prevailing winds, it might still find its way in thru the gable louver. It may be time to check out the possibility that there is air leaking out through other ceiling penetrations such as around the vent fan housing, light fixtures, etc. The bottom line is that you have moisture in the attic that shouldn't be there...or, if introduced to the attic, it shouldn't remain there. Finding the source of the moisture is job #1.

Michael
02-20-2008, 05:03 AM
Michael--
I see no snow blocking the ridge vents in your photo.

By properly designed inlet vents, I mean that you need an adequate amount of inlet vents to handle the airflow out the top side. Also, there should be an unobstructed flow from the soffitt into the attic. That's what the pink baffles you referred to are for. They need to be adequate in number and not blocked off in any way. Keep in mind that this is difficult to diagnose just based on what info you post. A site visit from someone who is local and who understands the issues would be beneficial.

The air flowing out the bath vent appears to be a good distance away from the gable inlet. However, warm air rises, and, depending on the direction of the prevailing winds, it might still find its way in thru the gable louver. It may be time to check out the possibility that there is air leaking out through other ceiling penetrations such as around the vent fan housing, light fixtures, etc. The bottom line is that you have moisture in the attic that shouldn't be there...or, if introduced to the attic, it shouldn't remain there. Finding the source of the moisture is job #1.

Hey Kevin thanks for the input, I am at a point of trying anything. I have even tried sending an email to This Old House, but no answer. I would love for an expert to come out and diagnose the problem. Do you know of anyone who could visit in New Hampshire?
The picture was taken late in the day when the tempature went up from 28 to 52 degrees and it was raining all day. it was a very extreme day as far as weather,(high humidity, a lot of melting and fog everywhere but to me my sheathing on the inside should not be getting wet, am I confused?)For at least a week before, the ridge vent had been snow covered, and because there is not much heat loss the snow didn't melt away.The pink baffles are place in every rafter bay.
Maybe by removing the blown-in insulation I will see the passages that may have air leaking from within the house.... This morning the RH level in the attic is 72% and the RH outside is 57%. The temp in the attic is 21 and the outside is 19 degrees. I know every house is different but this is a problem?

Roger Hankey
02-20-2008, 08:59 AM
[quote=Michael;32962]hello

My attic has at least 12 inches of blown in insulation in it, 6 inches of fiberglass blown in and 6inches of cellulose on top of that.

Note that the cellulose is ABOVE the fiberglass. Warm moist air from the house will pass through the warmer fiberglass. The cellulose is colder and the moisture can -and will - condense in the cellulose and be absorbed by the cellulose.

I suggest you get rid of all the attic insulation and apply air sealing methods and a vapor barrier before re-insulating. This can be done by spray foam as suggested by others. No need to improve ventilation. Ventilation's value is primarily to remove excess heat in summer. Adding more ventilation than needed for summer heat control simply increase the "stack effect" on the house. (warm air rising). Properly sealing the ceiling should negate the need for any more attic ventilation.

Michael
02-20-2008, 10:52 AM
[quote=Michael;32962]hello

My attic has at least 12 inches of blown in insulation in it, 6 inches of fiberglass blown in and 6inches of cellulose on top of that.

Note that the cellulose is ABOVE the fiberglass. Warm moist air from the house will pass through the warmer fiberglass. The cellulose is colder and the moisture can -and will - condense in the cellulose and be absorbed by the cellulose.

I suggest you get rid of all the attic insulation and apply air sealing methods and a vapor barrier before re-insulating. This can be done by spray foam as suggested by others. No need to improve ventilation. Ventilation's value is primarily to remove excess heat in summer. Adding more ventilation than needed for summer heat control simply increase the "stack effect" on the house. (warm air rising). Properly sealing the ceiling should negate the need for any more attic ventilation.

Roger you are recommending that I remove all the blown in insulation? After that should I add R30 faced inbetween the joists and then R19 in the opposite direction to create R49? Before laying new insulation seal all air leaks.....? I have sent an e-mail to Dr.Joe anyone have a phone number?

Roger Hankey
02-20-2008, 11:23 AM
YES, between removing old insulation and adding the new, you want to seal all air leaks from the house to the attic once the old insulation is removed. Your bottom (faced) layer of insulation should be only as thick (deep) as the framing (I'm assuming 2x6 ceiling joists) so it would be R-19 faced, then the crossways layer could be unfaced R-30.
Best wishes

Jerry Peck
02-20-2008, 02:48 PM
I have sent an e-mail to Dr.Joe anyone have a phone number?

Building Science Consulting
70 Main Street, Westford, MA 01886
978.589.5100

978-589-5100

Michael
02-20-2008, 03:25 PM
Building Science Consulting
70 Main Street, Westford, MA 01886
978.589.5100

978-589-5100


Thank you Jerry

I called and spoke to a lady by the name of Betsy. She asked me if I had a humidifier running on my furnace and if I had been running any type of vaporizer. Well my answer to her was yes on the humidifier but it had been set to the lowest level. She recommended that I remove the humidifier and that if it would make me feel better I could remove the blown in insulation and replaces with R19 faced between the joists and R30 unfaced in the opposite direction. Her real feeling is that the humid air running through my furnace is the problem. Well I will remove the humidifier and see what happens. I do think I should remove that blown-in since it has been wet before. What do you all think?

Roger Hankey
02-20-2008, 04:55 PM
The humidifier was likely a contributing factor. Now that you have it OFF, check the attic within 1/2 hour after sunrise on the next cold morning (tomorrow if it is below freezing). If you still have frost on the plywood then you certainly should consider removing the insulation. Once the cellulose gets damp it begins to compress into a mat, particularly the top layer. This compressed layer no longer has the original R-value. Unless you prove the ceiling is NOT leaking air to the attic (blower door and IR scan home performance tests), I would remove the insulation, seal the air leaks and install the new insulation.

Mike Schulz
02-20-2008, 05:54 PM
Michael, Michael, Michael...................Moisture problem in the home and we tried to give examples of things to look for that causes moisture. I forgot all about humidifiers. Hold out your hand and smack it with the other. :eek:

I would turn it off and wait a couple of days then check the attic.

Michael
02-21-2008, 04:44 AM
The humidifier was likely a contributing factor. Now that you have it OFF, check the attic within 1/2 hour after sunrise on the next cold morning (tomorrow if it is below freezing). If you still have frost on the plywood then you certainly should consider removing the insulation. Once the cellulose gets damp it begins to compress into a mat, particularly the top layer. This compressed layer no longer has the original R-value. Unless you prove the ceiling is NOT leaking air to the attic (blower door and IR scan home performance tests), I would remove the insulation, seal the air leaks and install the new insulation.

Ok, I checked the attic this morning just about a half hour before sunrise. I am trying to be very patience with this situation but it is very nerve racking.

The roof on the front as NO snow on it anymore and in the attic on that side, there was frost on all the nails, high and low. No frost on the gable walls. The back side of the roof has some snow on it but no frost, I am assuming the the snow is acting like an insulator. The temp in the attic was 10 and the outside was 6. The humidity outside was 61% and the attic humidity was 68-69%.

The crazy thing is that the humidity yesterday outside was 38% but the attic was 59%. During the night the humidity creep up as the temp dropped. I have my heat at night set to 68 degrees upstairs and 66 downstairs. The humidifier has been removed.
Removing the insulation is a big project for me or $1500 for a professional, I guess I need to get it down.

Question, while removing the insulation, will more damage occur while I am between removing and installing, especally if there is snow on the roof? I do have some time before I leave but I need to correct this before this season ends, to be sure it has been resolved. Please advise............

Mike Schulz
02-21-2008, 01:40 PM
(The crazy thing is that the humidity yesterday outside was 38% but the attic was 59%. During the night the humidity creep up as the temp dropped. I have my heat at night set to 68 degrees upstairs and 66 downstairs.)

Check it tonight.
Your humidifier could have been malfunctioning and allot of moisture was in the ducts and may need a Little while to dry out or the air in the home is laden with moisture and needs time to adjust.
I think humidifiers in HVAC systems should be banned. Mold and the like can build up in the ducts. If you need a humidifier buy a stand alone.

(The crazy thing is that the humidity yesterday outside was 38% but the attic was 59%) What's so crazy about that. You just turned the hose......I mean humidifier off. Give it a little time it's not going to change instantaneously.

Doug Haglund
02-22-2008, 05:03 AM
Outside humidity, Needs vapor barrier, Roofing nails to long.

Raymond Wand
02-22-2008, 05:10 AM
another thought...

Seal along all floor wall junctures (take the baseboard off) as warm moist air can be sucked up into the attic, and put foam gaskets behind all wall plugs and swithces.

Cheers,

John Arnold
02-22-2008, 06:02 AM
...Roofing nails to long...
?? Please elaborate.

Jerry Peck
02-22-2008, 06:09 AM
Roofing nails to long.

Doug,

"Roofing nails to long."????? :confused:

Please explain, I'm at a loss here.

Michael
02-22-2008, 09:27 AM
Well, I have noticed something since I took out the humidifier. The second floor windows didn't have water dew on them this morning despite the tempature being 9 degrees outside ( attic temp 16). Usaually the windows in my bedroom have dew on them and even seen ice on the inside. Especally since we close the blinds at night. Something is going on.......

I didn't have a chance to look in the attic this morning, but my RH sensor was reading 68% and that was what the RH % was outside.

Could this be my answer? We are expecting snow today 4 to 8 inches, my roof will be covered once again. Monday the temp will be going up to around 42. Things should react different this time during the melting process yes...no?

Roger Hankey
02-22-2008, 10:04 AM
Ok,The back side of the roof has some snow on it but no frost, I am assuming the the snow is acting like an insulator. The temp in the attic was 10 and the outside was 6. The humidity outside was 61% and the attic humidity was 68-69%.

The crazy thing is that the humidity yesterday outside was 38% but the attic was 59%. During the night the humidity creep up as the temp dropped. I have my heat at night set to 68 degrees upstairs and 66 downstairs. The humidifier has been removed.
Removing the insulation is a big project for me or $1500 for a professional, I guess I need to get it down.

Question, while removing the insulation, will more damage occur while I am between removing and installing, especally if there is snow on the roof? I do have some time before I leave but I need to correct this before this season ends, to be sure it has been resolved. Please advise............

I need the compass directions for front & back of house. I suspect the side with no snow is south facing. The presence of the snow will not likely have any effect. What will happen during the time the attic is not insulated is that the attic will be warm, frost will melt into the plywood, and the snow will melt off the roof. You will have some additional heating costs, so try to time the period of no insulation with a warm weather period. Removing the insulation is quite a chore, I agree. Look for an insulation contractor with a large truck mounted vacuum cleaner. It may be worthwhile to pay for the vacuum removal method since it will speed up the project a lot and reduce the potential for you or others stepping onto the ceiling.

Best wishes.

brian schmitt
02-22-2008, 12:16 PM
michael
i had your problems and i cured them by installing plastic sheeting in my underfloor crawlspace and installing additional underfloor venting. do you have raised floor? moisture was entering thru the crawlspace into the house. the windows totally quit condesating and the crawlspace dried out entirely!

Mike Schulz
02-22-2008, 01:31 PM
Brian,
Michael said he has a basement. He also said he was running a humidifier. I think shutting it off will solve his problem and no attic conditions need changed.

Raymond Wand
02-22-2008, 02:43 PM
Perhaps the house is too tight and the only escape is up through the attic. I am wondering if a Heat recovery ventilator might solve the problem of the house not getting enough balanced air exchnge.

Jeffrey L. Mathis
02-22-2008, 03:41 PM
I can't help myself. This is without a doubt the richest thread in the history of inspections. From the notion that the nails are too long to houses can be too tight. I suppose in theory houses can be too tight. But it ain't likely. And if the nails were shorter, you wouldn't have rust or beads of moisture, but you'd still have an imbanance caused by a stack effect and some yet to be determined defects between the heated space and the unheated attic. You're causing the problem. You just have to figure out how you're causing it.
Here's another source for you to go to: His name is Andy Yakim. Energy Services, Greenville (NC) Utilities. Don't ask. He's a Dr. Joe desciple and likely easier to actually talk to. 252-551-1525.
jlmathis

Rolland Pruner
02-22-2008, 03:45 PM
Michael:

I suspect a couple of items to check.
Is any bathroom, drayer or other type vents venting in the attic?

Next the pattern in picture sure looks like roof leaks

Next if you have to leave without fixing the problem, I suggest you put a De-humidifier in the attic untill time permits for more evaluation.


Hope this helps

Rolland Pruner

Raymond Wand
02-22-2008, 03:54 PM
Michael you said you had a humidifier on the furnace but you didn't say what type of furnace? Forced air oil/gas or electric?

Doug Haglund
02-22-2008, 04:03 PM
Jerry, If the roofing nails are sticking below sheathing alot will frost up & drip when gets warm I have seen this many of times gets insulation wet & high humidty. Something To look at.

Michael
02-22-2008, 04:52 PM
Michael you said you had a humidifier on the furnace but you didn't say what type of furnace? Forced air oil/gas or electric?

Raymond

I have forced hot air/ propane gas........with no humidifier I sure hope I don't dry things to much in the house....

Michael
02-22-2008, 05:01 PM
I can't help myself. This is without a doubt the richest thread in the history of inspections. From the notion that the nails are too long to houses can be too tight. I suppose in theory houses can be too tight. But it ain't likely. And if the nails were shorter, you wouldn't have rust or beads of moisture, but you'd still have an imbanance caused by a stack effect and some yet to be determined defects between the heated space and the unheated attic. You're causing the problem. You just have to figure out how you're causing it.
Here's another source for you to go to: His name is Andy Yakim. Energy Services, Greenville (NC) Utilities. Don't ask. He's a Dr. Joe desciple and likely easier to actually talk to. 252-551-1525.
jlmathis

I would just like to say thanks for all of you who are interested in helping me out. This is not an easy thing to figure out........ I have been up there looking for leaks found a pipe but it was already sealed from the inside from when it was just frame work......

Its snowing here and the humidity outside is 76% with the humidity in the attic at 75%...... temp is 25 outside and the attic is 30......

Jerry Peck
02-22-2008, 05:05 PM
Jerry, If the roofing nails are sticking below sheathing alot will frost up & drip when gets warm I have seen this many of times gets insulation wet & high humidty. Something To look at.


Doug,

When that happens, it is not that the nails are too long, it is whatever is causing the high humidity in the attic.

In this case, it was something that NONE OF US thought to ask ... did Michael have an humidifier (I have an excuse :cool: 'cause I'm not in 'humidifier country', if anything, anyone around here would need 'de-humidifiers :D ), but for you guys 'up there' ...

:D

At least Michael is now getting a handle on his problem.

Starting with the humidifier.

Then, after everything stables, remove the loose fill insulation, seal up *EVERY* opening from below (which, by the way, should have been sealed up anyway, either for fireblocking, draftstopping, or energy requirements), and then install batt insulation with the facing down. I like the 'first batt is only as thick as the bottom chord/ceiling joist' then the 'the second layer crosswise to the first and as thick as you want it'.

Jeffery,

"to houses can be too tight. I suppose in theory houses can be too tight."

Yes, houses can be too tight, unless that tightness is taken into consideration and everything designed around that fact, i.e., *NO* natural draft furnaces, heaters, fireplaces, etc., and fully sized make up air for all *exhausting* appliances, fans, etc., combined with heat exchangers for make the best use of the conditioned air being replaced with non-conditioned air.

Typically, you seal a house up tight, then you move the insulation to the bottom of the roof sheathing, making the attic semi-conditioned or conditioned space, taking away the attic problems.

Joe Klampfer
02-22-2008, 07:14 PM
WOW! I just caught onto this thread and am amazed at all the possible solutions offered. I think the best advice came from Kevin Barre. Air leaks between the living space and attic are confirmed by seeing lower attic humidity levels once the furnace humidifier was removed from the equation.

Introducing excessive humdity into the attic space needs to be eliminated so sealing those air leaks between the living space and attic is priority one. Once that's done you need to ensure full and adequate attic ventilation.

The large gable vents would definately short-circuit the soffit vents. The majority of air movement would flow directly from the gable vents up and out the ridge vents thus rendering the soffit vents ineffective. Over venting is not always a good idea.

Raymond Wand
02-22-2008, 07:26 PM
Gable vents usually only work when the wind is blowing parallel with the ridge.

Cheers,

Dave Ashby
02-23-2008, 04:35 AM
The best attic venting is soffit and ridge, which you have. But, you also have gable vents. The theory behind soffit and ridge is to allow outside air pressure up the soffit vents,into the attic via the baffles, holding back the insulation; then out the top, or the ridge vent. If you have gable vents, you are disrupting the flow with cross pressure and the two venting systems are "fighting", keeping the air stagnant. Block off the gable vents and direct all bath exhaust vents positively to the exterior with caps at the roof, not just in the direction of the ridge vent or into the soffit vents, get your money back for the gable vents, and....problem solved.

Also, you probably have a problem with ice daming. That's a whole other story. Sorry to sound so snippy about it, but your "restoration guys", I think you called them, should know this.

Michael
02-23-2008, 07:09 AM
WOW! I just caught onto this thread and am amazed at all the possible solutions offered. I think the best advice came from Kevin Barre. Air leaks between the living space and attic are confirmed by seeing lower attic humidity levels once the furnace humidifier was removed from the equation.

Introducing excessive humdity into the attic space needs to be eliminated so sealing those air leaks between the living space and attic is priority one. Once that's done you need to ensure full and adequate attic ventilation.

The large gable vents would definately short-circuit the soffit vents. The majority of air movement would flow directly from the gable vents up and out the ridge vents thus rendering the soffit vents ineffective. Over venting is not always a good idea.

Hello Joe

Its seems that the gable vents are there so that when the snow covers the ridge...... like today here are the pictures.....

When I didn't have gable end vents the gable walls frosted up, and I mean the whole wall frosted with big frost balls on the nails.

Raymond Wand
02-23-2008, 07:22 AM
The ridge vents won't work with snow covering them. The filter material in ridge vents over time becomes clogged with dust/dirt thus decreasing their functionality.

Cheers,

John Arnold
02-23-2008, 07:40 AM
The ridge vents won't work with snow covering them. The filter material in ridge vents over time becomes clogged with dust/dirt thus decreasing their functionality.

Cheers,

I have also read that all ridge vents are not created equal - some are quite restrictive to air flow, even before they get clogged with dust, etc.

Joe Klampfer
02-23-2008, 11:13 AM
Hi Michael,
When the ridge vents are blocked by snow, the short-circuit situation is corrected as the ventilation air would now flow from the soffit vents to the gables ensuring a fuller flow pattern.

Looks like all things point back to the air / moisture sealing between living space and attic. All openings and penetrations through the drywall ceiling below and at the interior wall top plates should be sealed off. That's when you will see the biggest improvement.

Michael
02-23-2008, 02:40 PM
Well I sealed all my light fixtures that were in the ceiling. Some had water stains around them, so I guess that was not helping. I attached a couple of pictures. Also I attached a picture of my attic hatch, as you can see very well insulated R38 faced.

Here is what I don't understand the humidity outside is 39% and the temp is 31. You would think things would be like that in the attic, or close to it, yet in my attic the humidity is 74% and the temp is 34. There is snow melting on top of the roof, the front part of the ridge vent seems to be open. The sheathing inside the attic is NOT wet to the touch, which is good I just think it is not normal for the humidity to be that high. It has to be that insulation now that I have eliminated everything else????

Raymond Wand
02-23-2008, 02:50 PM
Did you weatherstrip the attic hatch with foam tape? Also you could caulk around the attic hatch particularly the trim where air could by pass into the attic.

Also you should have a minimum of R32 attic insulation.

Cheers.

Michael
02-23-2008, 02:55 PM
Did you weatherstrip the attic hatch with foam tape? Also you could caulk around the attic hatch particularly the trim where air could by pass into the attic.

Also you should have a minimum of R32 attic insulation.

Cheers.

Yes on the weather strip and I sealed around the hatch. There is 12 inches of blown insulation.........

Raymond Wand
02-23-2008, 03:02 PM
Michael,

You have done quite a bit. I think it may be advisable to wait a few more days to see if the attic climate has changed for the better.

Cheers,

Jim Luttrall
02-23-2008, 06:07 PM
I second that opinion, Raymond. There will be quite a bit of moisture in that insulation and lumber; it will take some time to dry out.
If you have a week to wait, you might be surprised how much good you have done. If you have access to a moisture meter, that would tell you a little more about the moisture content of the building materials rather than just the RH of the air.

Chad Fabry
02-24-2008, 06:10 AM
I didn't read every response so if this is redundant I apologize.

Block off the gable the gable vents. Air enters the gable and almost immediately exits the ridge...or worse, air moving past the the house creates a low pressure area on a gable end and uses the ridge vent as an intake.

Ridge venting works well but only when there is a balanced (at least equal in area ) intake vent at the eave.

In most cases, perforated soffit material needs to be continuous (not a piece every two feet) to be effective as an intake.

The last consideration is whether you're measuring relative humidity or absolute humidity. 40% relative humidity at70 degrees will yield nearly 100 % relative humidity at 30 degrees.

Michael
02-24-2008, 04:12 PM
Well every day it seems that I find something that needs to be fix with the attic and its problem. I stated that my soffit P vents were open, that is I could see light throught them. Its seems that I was not alone in this assumtion. Well somthing told me to check from the outside, so here is what I found on the front of the house above the farmers porch. It looks like the vents were pushed down to the roof board that runs horizontal. Also on the gable end a 2 x 4 board was extending into the soffit blocking air flow. Here are some pictures......

I can't beleive this...... soon or later this will get corrected......I have made the most progress since I sent this thread. I can't believe I spent $1700 and had guys in person try and figure this out....

thank you

Mike Schulz
02-24-2008, 04:44 PM
Ahhhhhhh.........grasshopper.........youve done well.

Michael
02-24-2008, 04:58 PM
I am not sure if this is the cure all, I believe this insulation has been compromised but at least I am heading in the right direction.....

Jerry Peck
02-24-2008, 05:09 PM
Michael,

Some of the following has been said above, some has not, some you have stated you have corrected, some you have not stated that.

- Seal off all openings from the house. You've sealed off around the ceiling light boxes, however, have you pulled the insulation back where the walls are and sealed where the wiring, plumbing, etc., is coming up out of the top of the walls (coming up through the top plate)? While not as great of an issue the air around the light boxes regarding moisture from inside, there will be moisture in the walls which will come up through those unsealed openings, but, the more important issue regarding these openings and spaces is that sealing around these items coming through the top plate will also reduce the speed of spread of fire (and one of the two reasons - the main reason - these are required to be sealed anyway, energy air infiltration and exfiltration is the other reason - which also includes moisture traveling within that air).

- Exhaust all air from exhaust devices (exhaust fans, etc.) to the outdoors, not into the attic. This I think you have already done.

- Make sure (with a ventilated attic) that you have proper ventilation - and you just discovered the soffit vents were effectively blocked by the vent channels being pushed down to the fascia/sub fascia. These are just foam and can easily be cut or broken off.

- With soffit vents and ridge vents, and with the soffit vents actually working (looks like yours were not working), when the ridge vent gets covered with snow, the soffit vents work through cross ventilation soffit vent-to-soffit vent. With the soffit vents working properly, you should not need a gable vent. Now, if the gable vents are up at the very top of the gables, the gable vents would just act as extensions of the ridge vent and not really create a problem with the gable vents being there.

- Your loose fill cellulose insulation will be wet for quite awhile, if you remove it, you should be able eliminate a source of retained moisture, causing high relative humidity levels in the attic compared to outdoors.

- Your wet sheathing will take a while to dry out, also causing the attic relative humidity to be high.

- If your gable vent is not all the way up to the top of the gable, you may want to close it off and move it up to the top of the gable.

- Continuous soffit vents really have very little net free vent area (even if they were not blocked off, as yours were), you simply may not have enough net free vent area in the soffit vents to be sufficient for your attic ventilation needs. If your soffit is "fully vented", i.e., it has no 'non-vented' areas, then you might (at best) have 4-6 square inches of net free vent area per linear foot of soffit vent, with the minimum required net free vent area being 1 sf vent area to 300 sf attic area with soffit and ridge/or/gable vent, or 1 sf vent area to 150 sf attic area with only soffit vents. With soffit and ridge/gable vents, you would want approximately 50% of the area at the ridge/gable and 50% at the soffit. Approximately measure you attic area to determine the minimum require ventilation, then measure your soffit length and approximately determine the net free vent area provided by the soffit. With a ridge vent you might get as much as 18 square inches of net free vent area per linear foot of ridge vent.

As you can see, the restriction is more easily going to the the soffit vents as even if the ridge vent was accompanied with 2 soffit vents, the soffit vent area would still be about 1/2 of the ridge vent area. All you can do is run the numbers.

This post is getting long and long posts are harder to follow, so I will stop here.

Michael
02-24-2008, 05:39 PM
Michael,

Some of the following has been said above, some has not, some you have stated you have corrected, some you have not stated that.

- Seal off all openings from the house. You've sealed off around the ceiling light boxes, however, have you pulled the insulation back where the walls are and sealed where the wiring, plumbing, etc., is coming up out of the top of the walls (coming up through the top plate)? While not as great of an issue the air around the light boxes regarding moisture from inside, there will be moisture in the walls which will come up through those unsealed openings, but, the more important issue regarding these openings and spaces is that sealing around these items coming through the top plate will also reduce the speed of spread of fire (and one of the two reasons - the main reason - these are required to be sealed anyway, energy air infiltration and exfiltration is the other reason - which also includes moisture traveling within that air).

- Exhaust all air from exhaust devices (exhaust fans, etc.) to the outdoors, not into the attic. This I think you have already done.

- Make sure (with a ventilated attic) that you have proper ventilation - and you just discovered the soffit vents were effectively blocked by the vent channels being pushed down to the fascia/sub fascia. These are just foam and can easily be cut or broken off.

- With soffit vents and ridge vents, and with the soffit vents actually working (looks like yours were not working), when the ridge vent gets covered with snow, the soffit vents work through cross ventilation soffit vent-to-soffit vent. With the soffit vents working properly, you should not need a gable vent. Now, if the gable vents are up at the very top of the gables, the gable vents would just act as extensions of the ridge vent and not really create a problem with the gable vents being there.

- Your loose fill cellulose insulation will be wet for quite awhile, if you remove it, you should be able eliminate a source of retained moisture, causing high relative humidity levels in the attic compared to outdoors.

- Your wet sheathing will take a while to dry out, also causing the attic relative humidity to be high.

- If your gable vent is not all the way up to the top of the gable, you may want to close it off and move it up to the top of the gable.

- Continuous soffit vents really have very little net free vent area (even if they were not blocked off, as yours were), you simply may not have enough net free vent area in the soffit vents to be sufficient for your attic ventilation needs. If your soffit is "fully vented", i.e., it has no 'non-vented' areas, then you might (at best) have 4-6 square inches of net free vent area per linear foot of soffit vent, with the minimum required net free vent area being 1 sf vent area to 300 sf attic area with soffit and ridge/or/gable vent, or 1 sf vent area to 150 sf attic area with only soffit vents. With soffit and ridge/gable vents, you would want approximately 50% of the area at the ridge/gable and 50% at the soffit. Approximately measure you attic area to determine the minimum require ventilation, then measure your soffit length and approximately determine the net free vent area provided by the soffit. With a ridge vent you might get as much as 18 square inches of net free vent area per linear foot of ridge vent.

As you can see, the restriction is more easily going to the the soffit vents as even if the ridge vent was accompanied with 2 soffit vents, the soffit vent area would still be about 1/2 of the ridge vent area. All you can do is run the numbers.

This post is getting long and long posts are harder to follow, so I will stop here.

Jerry

Here are where my gable vents are located....

Jerry Peck
02-24-2008, 05:51 PM
Michael,

This would have been much better, as far as gable vent location goes.

Just make sure the net free vent area total (of one or two gable vents) meets at least minimum requirements).

Remember, you cannot just measure the 'opening area', you have to deduct for the 'louvers', on wood louvers, that typically only equates to about 25% of the total opening area as net free vent area, maybe less. Metal louvers are typically around 70% (if I am remembering correctly without looking it up).

Mike Schulz
02-24-2008, 08:06 PM
Don't sweat the gable vents;;;;;;;;;;;:p But fix the baffles

Stop the humidifier, seal things up. Insulate well and be done.

On my home I have soffit and ridge and attic fan. During the summer months the attic fan pulls from the soffits and during the winter when it's off the natural occurrence of the soffit and ridge combo takes over.

The playing in of cross ventilating from your new gable vents won't factor much in the soffit/ridge flow. You have quite a bit of height and heat rising to either gable or ridge vent is still going to pull from the soffit.

Timothy M. Barr
02-25-2008, 05:40 AM
check your soffit According to a roofing contractror I deal with There was a batch that did not work(Brand) I did a partial inspection and found what you are talking about. Turned out the soffit was bad

Jerry Peck
02-25-2008, 06:40 AM
Don't sweat the gable vents;;;;;;;;;;;:p

On my home I have soffit and ridge and attic fan. During the summer months the attic fan pulls from the soffits and during the winter when it's off the natural occurrence of the soffit and ridge combo takes over.

Er ... ummmm ... Mike, until his ridge vents are snow covered ... you know, like shown in his photos. :p


The playing in of cross ventilating from your new gable vents won't factor much in the soffit/ridge flow.

Possibly, until the ridge is ... ;) ... *snow covered*.

Jerry Peck
02-25-2008, 06:45 AM
check your soffit According to a roofing contractror I deal with There was a batch that did not work(Brand) I did a partial inspection and found what you are talking about. Turned out the soffit was bad

Timothy,

Not quite following you there.

You are referring to the continuous soffit vents?

"There was a batch that did not work(Brand) I did a partial inspection and found what you are talking about. Turned out the soffit was bad"

Did not work / bad how?

The perforations where not all the way through?

All continuous soffit vents are are (boy, that sounds strange "are are") continuous sheets of vinyl or aluminum with holes or raised perforations in them. About the only thing I can think of which 'would not work' and cause them to be 'bad' would be defective perforations.

Joe Klampfer
02-25-2008, 07:24 AM
Michael,
Looking at your photos where you seal-foamed around the light fixtures... it may be hard to see but I didn't see a poly vapor barrier. Is there one ?

Timothy M. Barr
02-25-2008, 07:51 AM
Holes were not all the way thru looked good just didn't work

Mike Schulz
02-25-2008, 04:22 PM
Ahhhhhhhhhhhh.....Oh great one. :p

If the peak is covered with snow then the gable ends will take it's place.
Either way hot air rises and pulls air into the soffit and out the gable ends or ridge.

But the problem was solved by removing the water hose........I mean humidifier.

Raymond Wand
02-25-2008, 04:29 PM
Gable vents will only work with wind moving parallel with the ridge.

Mike Schulz
02-25-2008, 05:21 PM
Gable vents will only work with wind moving parallel with the ridge.
True only if that is all there is for vents!


Gable vent intent was cross wind design because there was no other ventilation typically in the attic but end vents. Air will flow from soffit to gable, ridge vent, roof mounted caps, turbines, attic fans. etc.

Jerry Peck
02-25-2008, 05:21 PM
Ahhhhhhhhhhhh.....Oh great one. :p

If the peak is covered with snow then the gable ends will take it's place.

*I* am aware of that. :p

YOU sounded as though YOU were proposing to *do away with* the gable vents. :p :p

And that would not necessarily be a good thing with snow covered ridge vents. :eek:

Patrick Norton
02-29-2008, 07:38 AM
Mike,

Many attics have some condensation (especially on nails) in certain weather conditions and can be difficult to eliminate completely. Do you know how often and under what weather conditions there is high moisture in the attic? Is the attic dry most of the time?

If the moisture problem is as bad as you think it is there would be fungal/mold growth in the attic. I don't see any evidence of that in the pictures. Maybe there's no big problem. The attic looks pretty good to me.

I inspect many homes with ridge vents and gable vents. While it is recommended to use ridge vents with soffit vents alone, most of these homes do not have any ventilation problems (no ice damming, condensation or mold/mildew).

Maybe it is best to do further monitoring and logging the dampness and humidity levels over a period of time. I don't see any need to be in a hurry. The house is 7 years old and I don't see any mold in the attic.

Good luck.

Dave Mortensen
03-01-2008, 01:51 PM
Food for thought, here in Alaska builders seem to have caught on to the fact that roof penetrations lead to moisture problems in the attic maybe 4-5 years ago, that means we have a few hundred thousand homes with plenty of unsealed roof penetrations. Most of these homes (even the older ones, which would be pre-1960) have some kind of vapor barrier. It seems the house in question suffers directly from the lack of a vapor barrier even if most of the excessive moisture in the home is dealt with, you will always have the potential for freezing between the layers of insulation. Isn't the idea limiting the amount of moist air into the attic to the bare minimums as suggested (sealing all the penetrations, turning off the humidifier, etc.) somewhat of a moot point w/o installing a vapor barrier?

Mike Schulz
03-02-2008, 02:59 PM
I'm guessing it would depend the area you are from. Around here there's no barrier and predominately loose fill cellulose or fiberglass

Dave Mortensen
03-02-2008, 03:23 PM
That's true, it definitely seems to be a "problem" when there isn't a vapor barrier installed in Alaska homes.
I'm curious why there is not more of a problem during freeze/thaw periods for the homes you inspect. W/O the attic being conditioned space of course...

Raymond Wand
03-02-2008, 03:26 PM
There are interior paints that will function as a vapour barrier.

Dave Mortensen
03-02-2008, 03:49 PM
I have heard of those paints before and a large subdivision has been given the Municipality blessing to build w/o vapor barriers if they use these paints, but it seems that due to the frequent earthquakes we have, cracks will develop in the paint rendering it useless over time (might be a lot of time). So most, if not all, of the homes you inspect w/o a vapor barrier do not get commented on regarding the lack of a vp? Another locality difference...

Michael
03-02-2008, 04:04 PM
Hello

Thanks again for all the input. Here is what I have done in the last week.

I sealed off a pipe I found that had some foam around it but it wasn't completly sealed. The wall that separates the bathroom and a closet had aluminium tape on the seam, I sealed it up with foam. Also I fixed the P vents that were to far down.

Tommorrow I am having the blower door scan test to see if I have more leaks in the ceiling. The humidity readings in the attic during the day has been down to 55% when the humidity outside has been around 40%. The roof has been covered with snow for a week now, with some melting in the front side but not much in the back. The humidity was 77% last night, but the humidity outside was 83%. This morning is was about 68%.....

I think I am making progress without removing all that insulation. Here is a picture of what I sealed up..... the sliver duct is for the bathroom fan that was sitting in the soffit but now is exhausting outside the gable wall.

thanks

Jerry Peck
03-02-2008, 06:34 PM
Michael,

Does sound like you are making progress. Keep it up, you might get to where the level is acceptable without going the full distance.

Michael
03-03-2008, 04:17 PM
Well I had the blower door test and we found some leaks in the attic. most of them from interior walls, so I am going to have them sealed up. Also along the gable walls.

So after the attic floor is sealed it should solve my humidity and sheathing condensation problems?

Joe Klampfer
03-04-2008, 08:12 PM
It will definitely improve the situation, however, a lack of continuous vapor barrier will still allow for a certain amount of humidity to permeate through. If you find you still have higher than acceptable levels of humidity in the attic, you may consider using one of those vapor-barrier type ceiling paints on you next painting project.

Michael
03-05-2008, 04:19 AM
It will definitely improve the situation, however, a lack of continuous vapor barrier will still allow for a certain amount of humidity to permeate through. If you find you still have higher than acceptable levels of humidity in the attic, you may consider using one of those vapor-barrier type ceiling paints on you next painting project.


Joe

What is considered acceptable humidity level in the attic?

Jerry Peck
03-05-2008, 06:19 AM
What is considered acceptable humidity level in the attic?


Michael,

I don't know of any 'hard and fast' relative humidity number for the attic, however, if the attic is well ventilated, then the level should be similar to that of the outside air relative humidity (assuming that the outside air and the attic air is being exchanged sufficiently to provide adequate ventilation, making them one and the same, or thereabouts) only slightly lower.

While there may be some RH gain in the attic from interior moisture migrating up into the attic, the attic is typically warmer than the outside air, which makes the RH in the attic lower than the outside air (same amount of moisture in the air, but the air takes up more space being warmer, which drops the RH - warmer air holds more moisture than cooler air).

I.e., if it is raining outside, it should not be raining inside the attic because the RH is lower in the attic.

Here is a link concerning saturation vapor pressure and temperature which shows the degree to which warmer air holds moisture than cooler air. Relative Humidity of Air (http://www.engineeringtoolbox.com/relative-humidity-air-d_687.html)

As it says "Relative humidity by partial pressure", the chart is for "saturation pressure", but should be a good visual for the purpose to show the difference in RH also.

Note that the air can hold much less moisture at 10 degrees F than it can at 40 degrees F, approximately 1/4 as much.

Michael
03-05-2008, 10:37 AM
(Note that the air can hold much less moisture at 10 degrees F than it can at 40 degrees F, approximately 1/4 as much.)

Jerry

So why am I insulating so much, maybe I need some heat up there......

Mike Schulz
03-05-2008, 04:54 PM
(So why am I insulating so much, maybe I need some heat up there......)

No just don't use that humidifier or adjust it down (get rid of it). Make sure family is using exhaust fans when bathing and cooking.

Since you turned it off you said the attic is getting close to outside air Right?

It's not rocket science :rolleyes:

Jerry Peck
03-05-2008, 04:55 PM
So why am I insulating so much, maybe I need some heat up there......


That answer lies in why the recommendation to insulate at the underside of the roof sheathing instead of at the ceiling / attic floor was made.

Making that 'conditioned' or even 'semi-conditioned' space solves many problems, however, the reason for insulating as you are has nothing to do with 'moisture in the attic' but has to do with 'comfort in the house'.

If you were to remove the insulation entirely, you 'could' still heat the house, but at great expense, so, instead, the insulation is laid at the floor of the attic (it's the old fashioned and long acknowledged way to do things).

If you were to remove the ceiling / attic floor insulation and insulate at the underside of the roof sheathing AND (this would be critical then) seal up all ventilation between the attic and outside (you want no air exchange between the two), you would have similar energy considerations as you would if the insulation were down on the ceiling.

Michael
03-06-2008, 04:25 AM
(So why am I insulating so much, maybe I need some heat up there......)

No just don't use that humidifier or adjust it down (get rid of it). Make sure family is using exhaust fans when bathing and cooking.

Since you turned it off you said the attic is getting close to outside air Right?

It's not rocket science :rolleyes:

Mike

I don't think it is rocket science but something just doesn't make sense to me. This morning before sunrise, the attic readings were 78% RH and 29 degrees, and outside reading was 77% RH and 29 degrees. Most of the snow on the front of the house is gone and NO frost on any nails. But the last time I had these readings with the same roof conditions I have frost on the nails on the side of the sheathing where there is no snow.
I guess the humidity level is not an accurate measure for moisture?
I don't think I should condition the attic space at this point since I have spent money on venting the attic. I should continue to seal the ceiling?

This is a real headache........

Jim Luttrall
03-06-2008, 07:03 AM
I don't think it is rocket science but something just doesn't make sense to me. This morning before sunrise, the attic readings were 78% RH and 29 degrees, and outside reading was 77% RH and 29 degrees. Most of the snow on the front of the house is gone and NO frost on any nails. But the last time I had these readings with the same roof conditions I have frost on the nails on the side of the sheathing where there is no snow.
I guess the humidity level is not an accurate measure for moisture?



Michael, it sounds like you have made it just about as good as it can be from the readings. You can't make the attic any drier than the outside air when venting with outside air. You have sealed the attic floor tight and have provided plentiful outside air to vent. Relax. There may be days when you have close to 100% RH in the attic when it is raining outside, but it will pass. If you have ever been outside on a foggy day you know how the moisture sticks on everything, there is just too much water for the air to hold, but as soon as the sun comes out and heats the air the fog goes away. The moisture is still there, but the RELATIVE humidity goes down because the air is warmer and has the ability to hold more moisture. Relative humidity can be a tricky thing. Give it time and watch for symptoms of problems without worrying about the specific readings.

Michael
03-17-2008, 04:12 PM
Well I had the attic floor sealed today. A energy company came and sealed all walls to include the gable end walls.

I think it is as good as it is going to get, the RH in the attic went down to 31% which matched the outside RH.

I wanted to thank you all for helping me get this problem under control. The place where I am headed doesn't have any humidity problems but tempertures at 130 degrees is no treat.


One last thing, my sheathing has some splitting ( no leaking), can I put some kind of sealer on the sheathing so it will not get any worse, just like when you seal a outside deck? Or is it ok?

Thanks again
Michael