Thread: Need some help

I need to bounce this off of a couple of inspectors.
I received a call from a former client telling me about a problem he has incurred with his home. Background info: 3 year old two story, brick and vinyl, gable asphalt shingled roof, front of the house faces south, full basement, 6 roof vents with Soffit vents, some snow cover on the north side. I originally inspected the house on Oct 1st and it was 70 sunny.
He told me he had a water stain on both bathroom ceilings so he went into the attic to investigate. He discovered rotting OSB board at the bathroom roof vent. First I checked out the staining in bathrooms which were still wet, but when I went into the attic I did see the OSB starting to show surface rot at the bathroom roof vents but after digging into it the OSB was intack (vents terminate on the north side of the roof). However the entire north side of the OSB decking was wet except for the top foot from the ridge down and at the Soffit vents. There is a Lam beam that runs down the center of the house under the insulation, which was wet at the hatch. The south side of the gable was dry. Both bathrooms are under the south side deck so I ran my had down the foil vents and discovered the insulation was wet and water was inside of the foil vent. The temp of the attic was 63 with a 58% humidity level; the interior of the house was 68 with a 33% humidity level and outside was 45 with a 41% humidity level. He told me his humidistat is set at 30% however he fixed his humidifier (not working at the time of inspection) but now it runs constantly even when the furnace is not running.
Here were my thoughts on the conditions. I explained to him the bathroom foil vents either have condensation that turned to ice or had snow blown into them, which is now melting. The north side wetness was most likely due to frost because of a higher humidity level in the attic.
Just want to know anybody’s thoughts on these conditions.
I am going to recommend:

• A timer for the bathroom fans.
• An insulated vent material for the runs in the attic
• Shut down the Humidifier for now to see if the attic dries out
• A powered attic fan with a humidifier sensor.

Originally Posted by Rob Colecchi

I need to bounce this off of a couple of inspectors.
I received a call from a former client telling me about a problem he has incurred with his home. Background info: 3 year old two story, brick and vinyl, gable asphalt shingled roof, front of the house faces south, full basement, 6 roof vents with Soffit vents, some snow cover on the north side. I originally inspected the house on Oct 1st and it was 70 sunny.
He told me he had a water stain on both bathroom ceilings so he went into the attic to investigate. He discovered rotting OSB board at the bathroom roof vent. First I checked out the staining in bathrooms which were still wet, but when I went into the attic I did see the OSB starting to show surface rot at the bathroom roof vents but after digging into it the OSB was intack (vents terminate on the north side of the roof). However the entire north side of the OSB decking was wet except for the top foot from the ridge down and at the Soffit vents. There is a Lam beam that runs down the center of the house under the insulation, which was wet at the hatch. The south side of the gable was dry. Both bathrooms are under the south side deck so I ran my had down the foil vents and discovered the insulation was wet and water was inside of the foil vent. The temp of the attic was 63 with a 58% humidity level; the interior of the house was 68 with a 33% humidity level and outside was 45 with a 41% humidity level. He told me his humidistat is set at 30% however he fixed his humidifier (not working at the time of inspection) but now it runs constantly even when the furnace is not running.
Here were my thoughts on the conditions. I explained to him the bathroom foil vents either have condensation that turned to ice or had snow blown into them, which is now melting. The north side wetness was most likely due to frost because of a higher humidity level in the attic.
Just want to know anybody’s thoughts on these conditions.
I am going to recommend:

• A timer for the bathroom fans.
• An insulated vent material for the runs in the attic
• Shut down the Humidifier for now to see if the attic dries out
• A powered attic fan with a humidifier sensor.

When you say "foil vent" do you mean soil vent, vent stack or are you talking about the bathroom vent fan?

There are obviously high humidity levels in that attic. High humidity is a sign of a lack of ventilation and/or misdirected household exhaust fans.

Do the bathroom fans vent to the exterior of the home? Not towards the exterior as in the hose is pointed at a roof vent or a soffit vent.

The 6 roof vents actually do very little in ventilating an attic. Yes, air can be pulled in the entire soffit vent, assuming that it is open, but a roof vent only moves air in the rafter cavity that it is installed in. I always recommend ventillation improvements unless there are continuous soffit and continuous ridge vents.

You said that it was 63 degrees in the attic with an outside temp of 45. Very little is hapening in the way of attic insulation. It should be much cooler than that in the attic with proper insulation and ventilation.

Scott the bathroom vent material is foil.

Jon,
The bathroom fans vent to the exterior at a roof deadicated roof vent. 10 Inches of fiberglass 6 inch bats with 4 inches blown over.

Is it a regular roof vent with the foil hose shoved in it or a special vent designed to vent exhaust fans that the hose actually attaches to and is not open to the attic?

It seems to me that the attic is much warmer than I would have expected to find it if the outside temperature was 41 degrees.

Things to consider;

• Where does the dryer vent terminate? Does it run through the attic?
• What kind of condition is the ducting system in? You said the home was three years old... did you check to see if there was any moisture in the ducting system?
• Are the gables properly vented?
• You mentioned that there was some snow on the North side... Are there any dormers on either side where the OSB has been wet?
• Is there any possibility that recent weather has caused ice-damming around the dormers and the symptoms are just not raising their ugly heads?

Just thinin out-loud...

RR

Here is a related article I wrote:
Got Attic Mold? Lets Talk Energy Conservation!
It happens to countless homeowners around the end of the year – you make the annual visit to your attic to collect the holiday decorations and what do you find? Spots and blotches covering the bottom of the roof sheathing. Worse yet – it turns out to be attic mold!
What does energy conservation have to do with mold in the attic? Well if you take a step back and consider how the house behaves as system, they are often directly related.
Building science experts have long been using the “house as a system” approach to diagnose the cause and origin of building defects.
For example, ice dams. These are often caused by warm air seeping into the attic which causes the snow and ice on the roof to melt. The water drains to the edge of the roof (which is colder than the rest of the roof because it is an overhang and not warmed by the attic), freezes and creates an ice dam. As this process is repeated daily, the ice dam grows larger. Eventually water is forced under a shingle where it can seep into the house.
Understanding how the house behaves as a system and the various causes and effects is necessary to diagnose most building related problems.
But how about that attic mold? How did it get there?
Mold requires chronic moisture to form and to thrive, so source(s) of moisture must be present. Possibly the moisture came from outdoors. The roof is newer and a quick check of the roof shows no obvious damage or leaks.
Possibly the moisture came from indoors. During the heating season, the interior of the house frequently has high moisture levels, especially bathrooms and kitchens. A quick check shows that all bathroom fans, kitchen vents, etc. are properly ducted completely outdoors and not into the attic. The amount of insulation looks good and the attic is well ventilated.
Don’t give up – you are almost there! Remember the house as a system? You know that warm, moist air is in the house, but how is it getting into the attic?
By air leaks! Air leaks are the leading source of energy loss in most houses, and a frequent source of chronic moisture that can cause attic mold. Most homeowners are well aware of air leaks around windows and doors (especially old ones), but many overlook the numerous gaps leading directly into the attic!
Have a look around the attic and you may find large gaps around recessed lights and fans, holes where wires or pipes are installed, even large gaps around the chimney. And don’t overlook the whole house fan and especially the folding attic stair - a big, uninsulated hole in your ceiling that is often overlooked!
These gaps can add up to a large hole that allows warm, moist air from the house to flow right into the cold attic. The warm moist air condenses on the cold roof sheathing, creating chronically damp conditions that can lead to attic mold growth. And the energy loss – it can be like leaving a window open all winter long!
Seal these air leaks and you stop a significant moisture source. And just think of all the energy you can save and the cold drafts you can stop!
Mark D. Tyrol is a Professional Engineer specializing in cause and origin of construction defects. He developed several residential energy conservation products including an attic stair cover and a fireplace draftstopper. To learn more visit www.batticdoor.com

Well Mark,

Your previuos article that you posted was pretty much where I was headed with my line of questioning...

One other thing that was mentioned was the way and amount in which the insulation was installed. If I read one of the previous posts correctly, there are 10 inches of insulation-- that was 6 inches of batt material with 4 inches blown ontop of it. If this is done the way I envision it, there often are quite alog of air-gaps in the insulation itself (very large gaps) where the very most would be approximatley 4 inches of insulation (at the most).

Another question, while in the attic, was there evidence that many areas of the insulation had been disturbed and/or walked... i'd bet by now the situation has been exasorbated to the point of having even greater issues related to insulation coverage.

I've seen batts installed in the attic where it looked like a corn-field had been plowed the gaps were so bad.

Rich

Almost every new house that I have inspected has had the soffit vents blocked by the insulation being pushed all of the way tight to the roof decking at the eaves. This will negate both the soffit vents and the function of the ridge vent (if present). Be sure to check for that, in addition to your other ideas.

I have to agree that it is too warm in that attic and it is lacking proper ventilation.

The bathroom vents are a "Red Hearing" and are taking you in the wrong direction, I think. That is not to say that they are not a problem, but I don't think that they are the main problem.

Could you see the ceiling joist or were they covered with insulation?

Thanks for all of the comments.

Jon: special vent designed, it's the pix on the left.

Richard: Dryer is located in the basement and it is a direct vent to the exterior. 2nd story has floor vents no moisture in them. All of the soffit vents are open and the roof has 6 static square metal roof vents. No dormers. The remaining snow was towards the top of the roof not the bottom.

Mark and Richard: Great artical! I did not see any missing insulation and low spots, however I did not want to disturb all of his insulation, but that is something I will look into.

Jim: the soffit vents are open. In fact the OSB that is directly over the soffit are dry.

Scott: I agree with the bathroom vent comment. The ceiling joist are covered. There is a lam beam covered by insulation but I did notice it was wet but only near the hatch.

I have attached some pix if they help at all.

I'm not a cold weather guy since we don't have winter attic venting problems for the most part. I would be looking with real suspicion at the newly repaired humidifier that does not cycle off.

but now it runs constantly even when the furnace is not running

That seems to be the one major change since the inspection other than the weather. No matter how much ventilation and insulation, it can be overcome with extreme conditions. The indoor humidity level does not seem excessive, but remember that is a one time measurement and it seems to contradict the actuality that the humidifier runs constantly.

Additional ventilation and insulation may bring the attic back into normal parameters, but reducing the amount of humidity generated in the house would too.

I think the first picture (of your last post) tells volumes....

The areas in the attic that are (relatively) low are warm enough to melt the smow on the roof (looks to be facing North or East). While the top section of the attic/roof is still cold enough to keep the snow on the roof from melting.

If you look on that left slope, the bottom of the snow (where the snow has melted and meets the shingle) is no longer snow, but is now iced over. That tells me that the lower section of the inside of the attic is warming the roof enough to melt the smow.

I would definately be looking for:

• Poorly distributed/ not enough insulation (installed in corn-rows)
• Poor sealing between the ceiling and the attic penetrations
• Poor attic ventilation

Those are going to give you your biggest bang for your buck. JMFO

Rieech

It's hard for me to tell, but is that foil vent hose going to one of the roof vents or the verticle gas looking vent? By looking at the drips of condensation going down the rafter on the left of the vent, I assume that we are looking down at this assembly from the ridge area and this is at one of the roof vent locations.

Those roof vents are just regular roof vents, not exhaust fan vents. It looks to me like a home made sheet metal collar attached to the underside of the roof decking with a self tapping sheet metal screw in each corner. The black lines spraying out the sides tell me that more pressure is being forced into that assembly than it is able to expell through the vent above the roof line. The escaping air and moisture is causing the black lines and if you notice, the rafter on the left is wetter than the one on the right. There is more air leakage on that side.

Just my $0.02

Jon,
Yes that is a foil vent from the bathroom fan housing to a roof termination cap. The pix is taken from the ridge looking down. I had the same thought on the black lines but was not sure.

I would just like to say Thanks to everyone who responded!