In Sept.2001 I had a local, reputable, roofing contractor (Mike-the owner) re-shingle my house. I had one layer of fiberglass shingles in place from when the house was built still on the house and they were cracking. The contractor laid the new CertainTeed landmark shingles of them. Since that time we have developed a mold problem in the attic, maybe even a minor leak somewhere. <!—-><!—-> <!—->
2003 I paid Mike to re-route the exhaust system from the upstairs bath rooms thinking this was the problem. In 2004 he brought me an article published by Cetainteed titled “Ventilation Standards and System”. Due to the fact he was running out of ideas on how to resolve this problem; he suggested we install a power vent, so we did. Here we are 2005 and the problem hasn’t changed. Oh, and the problem seems shows itself during the winter months more prominently. Something about a good coating of snow really makes the problem standout.
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It is a hip roof as described in your article, but the vent is not getting the job done and I am very concerned. <!—-><!—->
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What I would like is some direction !!!
Replies
My guess is that this has nothing to do with the roof. You've got a moisture source somewhere. How about some more info? Crawl space or basement? Isulation type? The power vent is probably not working in the winter since it's thermostatically controlled.
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it does work in the winter ( to much) , although it does shut down late at night some nights. In the summer it only comes on when it is really humid.
The house is a colonial...
Check your soffit vents. If they are eave style, they can get clogged. While they are off, look inside the eaver and check that your attic insulation is not blocking the air flow.
If the eaves aren't supplying the correct volume, the attic vent (gable or ridge) will pull warm, moist air into the attic from your ceiling penetrations (lights) and wire/plumbing holes if they weren't sealed to the top plates.
Troy Sprout
Square, Level & Plumb Renovations
I did check the sofits and 95% of them are very very open with a styrofoam insert to ensure the blow-in insulation does not plug them. I do have maybe gaps between 4-5 rafters which have broken styrofoam, but they are still mostly open.
Where is the mold in the attic? Near the peak, down low, only on one side. Near the kitchen, bath????
There is a side which doesn't look like it has been covered, ceiling integrity.
The standards and 'rules of thumb' are based on the ceiling plane being relatively well sealed. If you have old, non-IC rated or poorly installed IC rated, high-hat light fixtures projecting into the attic they can leak enough hot, moist air into an attic that no reasonable level of ventilation will help.
Similarly if the plumbing, wiring and duct work penetrate the ceiling plane or down through the top plates of walls and are not tightly sealed it can produce such a chimney effect that adding ventilation won't help much.
Also if the ceiling plane has holes adding a power ventilator, especially if not carefully balanced by intake area, can greatly increase this flow of air up and out of the interior envelope. You paid money to heat or cool that air and having it sucked out isn't going top save you money.
Don't assume that if you see loads of fiberglass or mineral wool insulation that the ceiling plane is not leaking air. These fiber based insulation don't work effectively as barriers to air movement. Crawl around the attic with a strong light. Look for stained insulation. Find a stained and dust spot and your close to an air leak.
Caulk, caulk, spray foam, foil tape and sheet metal can be used to seal gaps and restore the integrity of the ceiling plane. Once sealed you may find the existing ventilation is able to keep up with the inflow of moisture and the damp spots will go away.
Thanks,
I have not looked hard at this issue, I will go after it. Heck I needed somthing to do on New Years eve anyway.
Again thanks for the idea, I hope it works !
One trick an good HI told me about was to turn up the heat in the winter and climb into the attic. Added heat will increase any air movement so any leaks are easier to find.Close the hatch to recreate normal conditions. Make sure you have someone below who can let you out if the hatch gets stuck. Bring a strong light or two. A head type light is nice. Bring a couple of sticks of incense or a 'punk'. Carefully light it. Might be nice to keep a spray bottle of water in case the fire gets away from you. I have seen it happen so being prepared is a good thing. Look at the insulation for dust marks that indicate leaks. Use the smoke from the incense stick to note how the air is moving. Track any currents back to the source. HI told me he has never checked on that didn't have leaks serious enough to seal.Then it is a matter of sealing and retesting. As you seal a large leak the smaller ones will become more obvious so several cycles of identify and seal will be needed. Just work it a little at a time.Of course this might not solve your moisture problem. Shouldn't make it any worse and Evey hole sealed is energy saved so even if it doesn't solve the particular problem it can be a worthwhile project.Happy New Year.
Been one hell of a year. Hopefully the this one will be better. Maybe, just maybe, if we work together and use our heads we can get this one right.