Air Sealing Attic - Insulation - DIY Chatroom - DIY Home ...

I think your approach is ok. Does the house have a ridge vent or gable ends? Hard to tell from the picture. If yes on the ridge, you should have the whole soffit ventilated as much as possible. Don't have a guideline for how many vents per foot off the top of my head but if you had siding on there and you were going to cover up the soffit with trim, I would tell you to vent the length of the run on each side. Doing so now would require you to find a continuous vent like 30 feet long (or whatever it is) but that probably is not strictly necessary. Also, you could close up the gable end vents if there is a ridge vent. If no ridge vent, then leave the gable ends alone. It is not ideal but getting a ridge vent in place would be a next step.

IMO, any old insulation should just be chucked and replaced with new stuff. For true air sealing, you will need to expose the whole attic floor (not necessarily all at once if you are doing this as a DIY) so that you can get to every significant crack where all drywall/walls meet. Same with plumbing runs, junction boxes, etc.

In my home, the pitch of the roof is fairly low. Don't have a number for you but I am 6'1" and about 160. I could barely fit in the cavities plus I had to lay on a board of plywood. Lots of reaching and hitting my head on the roof deck. What a pita! Blood was shed on that job. If you are a big guy, either lose some weight or get a punk kid in there : - )

Also, consider sealing the outside wall perimeter/ceiling joint in the attic. Yes, this is at the absolute tightest reach on your home. It will suck. I had good sized open joints. I used silicone caulk because it was hard to reach a spray foam can there. I had to use latex gloves to spread the caulk around in the gap. Spray foam would work ok but you need to plan ahead if you are using the cans. Those cans are a one time shot and the best I could ever do was get two uses out of them. Just remember, moving from one joist cavity to another is not instantaneous. Factor that time in as well. After placing in the air baffles, I also blocked/supported the baffles with both fiberglass batting and foamed in rigid foam (a bit overkill here). You have to allow for air to get into the attic but you can direct it so that it does not wash down the exterior walls. Hence the reason why I said you should seal up the outer perimeter wall/ceiling gap (if it exists on your home).

One last thing, any caulk or spray foam you use should be done with a cleaned surface. You will need a vacuum up there to make that happen.

---

Last edited by algored2deth; Today at 01:20 PM.

Source: http://www.diychatroom.com/f103/air-sealing-attic-104936/

simon and garfunkel paul mcdonald bac susan lucci federal tax forms shenae grimes water for elephants