Attic Venting


  #1  
Old 02-01-10, 07:23 PM
D
Member
Thread Starter
Join Date: Jan 2010
Location: canada
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Attic Venting

Hey guys, well here's my first post, My lady and I have recently bought our first home, the price was right as it was a fixxer upper.

The inspector had been in the attic and informed us there was no venting, the hood vent on stove comes into the attic just past the insulation, the bathroom vent goes knowhere, no gable vents or soffit vents. Well a couple months later on the west coast of Vancouver Island I finally got in there and it was looking pretty rough, the ceiling is pretty black and grey mold is forming in patches.

I'm gonna vent the stove tomorrow and bring it out the side of the roof, planning on installing some gable vents. The sofits are closed up with wood panneling and I plan to drill holes and place in a few circular vents. I'm new to all this, and just wondering If I'm on the right track.. I want to get all these vents in and see If it clears up in the next month, also hoping this mold isn't harming us as I have my pregnant lady in the house... This is just one of the many fix's the house needs.

Thanks

Dylan
 
  #2  
Old 02-01-10, 07:42 PM
B
Member
Join Date: Oct 2008
Location: New England
Posts: 9,460
Received 47 Upvotes on 43 Posts
Hi dillbike and welcome to the forum,
fortunately the air in the attic should be leaking out and not back into the house and the venting will help that process.

General venting guidelines are one sq. ft. of vent area for every 150 sq, ft of attic floor. Distribute thar 50/50 upper and lower areas. A big however though. That is the number for a well air sealed attic. If the leaks into the attic are not well sealed, that venting area should be increased. Now, here is the good news. Air sealing is relatively easy, reduces the amount of venting needed, and saves on heating costs. It's a win win for sure.

Air sealing refers to tops of walls where air leaking in through electrical boxes or under walls can find its way to the top of the walls and squeeze between the drywall and the framing into the attic. Plus all of the holes drilled for electrical and plumbing. and the big gaps like around chimneys and framing errors where drop ceilings and overhanging floors provide open access for basement of household air to flow into the attic. It is the inside warm moist air that is transporting that moisture up there. I have a long article on air sealing which will save a bundle.


For your vents, use as much rigid duct as possible and allow for moisture that may condense inside. Insulation can reduce any condensation and a slope to the outside will take care of what might develop.

Bud
 
  #3  
Old 02-03-10, 09:52 AM
D
Member
Thread Starter
Join Date: Jan 2010
Location: canada
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
Thanks for the great info Bud, as far as sealing things up, is using caulking and expandable foam okay? I pulled away some of the soffit and the insulation is pretty tight in there, was thinking putting baffles in there, should these go between every roof truss?

Thanks!
 
  #4  
Old 02-03-10, 12:10 PM
B
Member
Join Date: Oct 2008
Location: New England
Posts: 9,460
Received 47 Upvotes on 43 Posts
Between every truss is correct. Fire rated caulking or FR foam for any holes a fire could follow. That keeps any future inspectors happy. Sheet metal and caulk or foam for larger gaps. Even sheetrock works. Here is a good link, a bit slow to open but worth the wait.
http://www.efficiencyvermont.com/ste...ide_062507.pdf

Bud
 
 

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