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  1. #1
    Michael's Avatar
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    Default Attic Problems moisture.....

    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

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  2. #2
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    Default Re: Attic Problems moisture.....

    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.


  3. #3
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    Default Re: Attic Problems moisture.....

    Michael,

    Go here, Building Science Corporation - Technical Resources , 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...l_Climates.pdf

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  4. #4
    Aaron Miller's Avatar
    Aaron Miller Guest

    Default Re: Attic Problems moisture.....

    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


  5. #5
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    Default Re: Attic Problems moisture.....

    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,


  6. #6
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Raymond Wand View Post
    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.


  7. #7
    Richard Stanley's Avatar
    Richard Stanley Guest

    Default Re: Attic Problems moisture.....

    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.


  8. #8
    Jeff Remas's Avatar
    Jeff Remas Guest

    Default Re: Attic Problems moisture.....

    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

    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)


  9. #9
    Aaron Miller's Avatar
    Aaron Miller Guest

    Default Re: Attic Problems moisture.....

    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


  10. #10
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    Default Re: Attic Problems moisture.....

    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.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  11. #11
    Aaron Miller's Avatar
    Aaron Miller Guest

    Default Re: Attic Problems moisture.....

    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


  12. #12
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    Default Re: Attic Problems moisture.....

    Btw is there a vapour barrier installed on the attic floor under the insulation?


  13. #13
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Jim Luttrall View Post
    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.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  14. #14
    Roger Hankey's Avatar
    Roger Hankey Guest

    Default Re: Attic Problems moisture.....

    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


  15. #15
    Kevin Barre's Avatar
    Kevin Barre Guest

    Default Re: Attic Problems moisture.....

    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.


  16. #16
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    Default Re: Attic Problems moisture.....

    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?

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  17. #17
    Kevin Barre's Avatar
    Kevin Barre Guest

    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Jerry Peck View Post
    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?
    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.

    Last edited by Kevin Barre; 02-19-2008 at 05:49 PM. Reason: further clarification

  18. #18
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    Exclamation Re: Attic Problems moisture.....

    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

    Last edited by Mike Schulz; 02-19-2008 at 05:45 PM.
    Mike Schulz License 393
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  19. #19
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    Default Re: Attic Problems moisture.....

    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....


  20. #20
    Michael's Avatar
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    Default Re: Attic Problems moisture.....

    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.


  21. #21
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    Default Re: Attic Problems moisture.....

    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 Schulz License 393
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  22. #22
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    Default Re: Attic Problems moisture.....

    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.


  23. #23
    Kevin Barre's Avatar
    Kevin Barre Guest

    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Michael View Post
    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


  24. #24
    Michael's Avatar
    Michael Guest

    Default Re: Attic Problems moisture.....

    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.




  25. #25
    Michael's Avatar
    Michael Guest

    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Raymond Wand View Post
    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...


  26. #26
    Michael's Avatar
    Michael Guest

    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Kevin Barre View Post
    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?

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  27. #27
    Michael's Avatar
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Mike Schulz View Post
    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.


  28. #28
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Michael View Post
    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.

    Quote Originally Posted by Michael View Post
    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.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  29. #29
    Kevin Barre's Avatar
    Kevin Barre Guest

    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Michael View Post
    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.

    Last edited by Kevin Barre; 02-19-2008 at 07:49 PM.

  30. #30
    Michael's Avatar
    Michael Guest

    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Kevin Barre View Post
    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?


  31. #31
    Roger Hankey's Avatar
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    Default Re: Attic Problems moisture.....

    [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.


  32. #32
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    Default Re: Attic Problems moisture.....

    [quote=Roger Hankey;33114]
    Quote Originally Posted by Michael View Post
    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?


  33. #33
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    Default Re: Attic Problems moisture.....

    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


  34. #34
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Michael View Post
    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

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  35. #35
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Jerry Peck View Post
    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?


  36. #36
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    Default Re: Attic Problems moisture.....

    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.


  37. #37
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    Cool Re: Attic Problems moisture.....

    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.

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

    Mike Schulz License 393
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  38. #38
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Roger Hankey View Post
    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............

    Last edited by Michael; 02-21-2008 at 05:16 AM.

  39. #39
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    Default Re: Attic Problems moisture.....

    (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.

    Mike Schulz License 393
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  40. #40
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    Default Re: Attic Problems moisture.....

    Outside humidity, Needs vapor barrier, Roofing nails to long.


  41. #41
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    Default Re: Attic Problems moisture.....

    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,


  42. #42
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Doug Haglund View Post
    ...Roofing nails to long...
    ?? Please elaborate.


  43. #43
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Doug Haglund View Post
    Roofing nails to long.
    Doug,

    "Roofing nails to long."?????

    Please explain, I'm at a loss here.

    Last edited by Jerry Peck; 02-22-2008 at 06:11 AM. Reason: never mind, after I clicked on it to reply, then clicked to post this - John had already asked the same question.
    Jerry Peck
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  44. #44
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    Default Re: Attic Problems moisture.....

    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?


  45. #45
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Michael View Post
    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.


  46. #46
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    Default Re: Attic Problems moisture.....

    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!


  47. #47
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    Default Re: Attic Problems moisture.....

    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.

    Mike Schulz License 393
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    www.houseinspections.com

  48. #48
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    Default Re: Attic Problems moisture.....

    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.


  49. #49
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    Default Re: Attic Problems moisture.....

    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


  50. #50

    Default Re: Attic Problems moisture.....

    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


  51. #51
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    Default Re: Attic Problems moisture.....

    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?


  52. #52
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    Doug Haglund Guest

    Default Re: Attic Problems moisture.....

    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.


  53. #53
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    Michael Guest

    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Raymond Wand View Post
    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....


  54. #54
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    Michael Guest

    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Jeffrey L. Mathis View Post
    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......


  55. #55
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Doug Haglund View Post
    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 'cause I'm not in 'humidifier country', if anything, anyone around here would need 'de-humidifiers ), but for you guys 'up there' ...



    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.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  56. #56
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    Default Re: Attic Problems moisture.....

    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.


  57. #57
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    Default Re: Attic Problems moisture.....

    Gable vents usually only work when the wind is blowing parallel with the ridge.

    Cheers,


  58. #58
    Dave Ashby's Avatar
    Dave Ashby Guest

    Default Re: Attic Problems moisture.....

    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.


  59. #59
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Joe Klampfer View Post
    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.

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  60. #60
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    Default Re: Attic Problems moisture.....

    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,


  61. #61
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Raymond Wand View Post
    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.


  62. #62
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    Default Re: Attic Problems moisture.....

    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.


  63. #63
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    Default Re: Attic Problems moisture.....

    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????

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    Last edited by Michael; 02-23-2008 at 02:47 PM.

  64. #64
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    Default Re: Attic Problems moisture.....

    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.


  65. #65
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    Default Re: Attic Problems moisture.....

    Quote Originally Posted by Raymond Wand View Post
    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.........


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