Attic insulation and moisture problems


  #1  
Old 02-24-03, 06:17 PM
lrg51
Visiting Guest
Posts: n/a
Attic insulation and moisture problems

I own a ranch style home in Buffalo, NY area built in 1954. I have a serious condensation problem on the ceiling of the two back bedrooms and windows on the east end (colder) side of the house. Condensation has been a problem since I purchased the house six years ago and only appears along the exposed walls usually when snow accumulates on the roof. This has created a mold problem that I have to keep after quite a bit during the cold winter months.

Last fall, I had the exterior of the house insulated, wrapped in Tyvek, new insulated windows, re-sided, vented the soffets and a new roof installed with ridge vent. The condensation is still as much of a problem as before. I suspect the insulation in the attic, plaster, and wood beams never completely dry out during the warmer months. And I'm pretty sure that the insulation was not properly installed so that it could be preventing adequate airflow from the soffets to the roof vent.

I am preparing to remove the insulation this spring and allow this area to dry completely before installing new insulation. Any recommendations for drying/treating the area if I find mold? What do you recommend for insulation... batting or blown in insulation? What R value should I consider?

The attic is only 6 feet at the peak and is not insulated with one side opening over an unheated garage.

Could use your help to solve the moisture problem. Thank you in advance.
 
  #2  
Old 02-24-03, 06:35 PM
C
Member
Join Date: Nov 2001
Location: Taylors, SC
Posts: 9,483
Received 0 Votes on 0 Posts
Make sure that the soffit vents are not blocked by insulation. There is a soffit vent device of foam that fits along the roof down to the soffit interiorly to keep the insulation from blocking the soffit vents.

I don't live in snow country, but I recall that ice dams can be a problem. Does the snow accumulate to the point that this may be a consideration?
 
  #3  
Old 02-24-03, 06:43 PM
lrg51
Visiting Guest
Posts: n/a
Ice damming should not be a problem since I had a 72" water vapor barrier installed under the new roof.

Someone also told me that its possible that the insulation may not be installed properly to cover all of the attic ceiling (it should extend out over the wall plate but not over the eave). Although I have not been able to check on this, I guess that's another possibility.
 
  #4  
Old 02-24-03, 07:48 PM
Doug Aleshire's Avatar
Member
Join Date: Feb 2002
Location: United States
Posts: 4,679
Received 0 Votes on 0 Posts
lrg51,

Ice damming occurs due to insufficient attic insulation and air leakage into the roof space. The loss of heat into the attic causes snow on the roof to melt and then refreeze when the melted water reaches a colder part of the roof.

The accumulation of ice at the eaves and valleys of roofs (ice damming) may prevent melted ice and snow from draining off the roof, and cause the water to back up under the roofing, and leak into the building interior. Ice damming may cause wetting of the insulation in roofs and walls, and damage interior finishes, eaves and gutters. If the problem persists, it may lead to decay of members and costly structural repairs.

To prevent ice damming, the attic must be well ventilated. This will allow the roof to maintain a more uniform temperature by quickly removing any warm air that reaches the attic space. Also, the ceiling must have an adequately sealed air and vapour barrier, and be well insulated to prevent excessive heat loss to the attic.

And NO, this has nothing to do with gutters being the problem! They may compound the problem if you aren't venting the attic space properly but removal of gutters doesn't SOLVE the problem.

Ensure that Air Baffles are placed every other rafter space - you should be able to see light through each one as you extend them past your ext wall into the soffit area, since you said they are now vented.

I have attached some links with good pics to help in determining what or how you should resolve your issues, once and for all.

http://www.allaroundthehouse.com/lib.ghi.na23.htm

http://www.model-a-roofing.com/ice.htm

http://doityourself.com/roofing/icedam.htm

Hope this helps you resolve all your issues!
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: