How to insulate basement walls?

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velvetfoot

Minister of Fire
Dec 5, 2005
10,202
Sand Lake, NY
It gets pretty cold down there (I was using my IR temp gun down there yesterday and it was pretty cold even though it wasn't that cold outside.)

Foam (I was thinking 2") has to be covered with drywall but apparently the whole assembly can't just be glued cause it could melt with a fire.
What is the minimum needed to hold it on (supplementing the glue), goal being to minimize heat transmission.
It's looking like a stud wall with maybe fiberglass is one way, but more material and I would think hassle, but would result in wall that things could be hung off of.
I've looked at that Building Sciences site before.

Sorry for nearly incomprehensible post.
 
Well I think I'm going to use 2" tongue in groove Dow styrofoam and attach it to the wall with something like 1x4 furring strips held on by TapCons. Paperless (probably if not too expensive) drywall over top.
 
Thanks.
I messed a little with fiberglass insulation the other day.
I hate that stuff (the physiologial effects anyway).
 
I had this issue. My solution was to put up a continuous poly barrier, furring strips 16 inches on center, polyisocyanurate foam in between, and then drywall over the top. The poly foam should have foil radiant barrier on both sides. For some reason, Tapcons proved a total failure in my installation. I wound up buying one of those .22 caliber nail guns (Lowes has them), and it made short work of installing the furring strips. YOu can go with 2x4's if you like and use fiberglass rolled insulation, but I spent the extra money for sheet foam. It made an absolute world of difference. Good luck!
 
velvetfoot said:
Well I think I'm going to use 2" tongue in groove Dow styrofoam and attach it to the wall with something like 1x4 furring strips held on by TapCons. Paperless (probably if not too expensive) drywall over top.
Velvet, I just did part of my basement exactly this way (except I used the 1" board cause that's all I could get locally), and I'm very pleased with the results. Drilling into 77-year-old concrete for the Tapcons was a chore but it all worked out. I also put 2" strofoam around the sill joists and then caulked it to the Dow board so there are no gaps anywhere on the wall.
 
if it were me i'd think of the future or at least a little up the road. if you are going to use strapping and a 22 cal nail gun why not just throw up 2x3's use either fiberglass batts or styrofoam board or both. set up your stud walls and install electric outlet boxes for future.

if you don't know how to do the electrical let me know and i'll walk you thru it
i'm a master electrician.

frank
 
Steel studs and spray foam (the blue stuff) with sheetrock on top. No vapor barrier needed.
 
Precaud,

Aren't there reasons you might have to get into that sill area?
For instance, yesterday I took out some fiberglass batts in a sill area in order to drill some holes in the floor sheathing above to install a wire.

Also, would you insulate over the main sewer (in my case septic tank) trap? Could it freeze? Should it be left exposed and warmed?
 
If you can get access to a hammer drill for drilling in concrete or brick, you'll be glad you did.

The hammer drill looks just like a regular drill, except that as the bit rotates, it also pounds like a jack-hammer. You have to make sure you get drill bits made for a hammer drill (sometimes labeled percussion drill) so that you don't ruin your bits.

-SF
 
velvetfoot said:
Precaud,

Aren't there reasons you might have to get into that sill area?
For instance, yesterday I took out some fiberglass batts in a sill area in order to drill some holes in the floor sheathing above to install a wire.

Also, would you insulate over the main sewer (in my case septic tank) trap? Could it freeze? Should it be left exposed and warmed?

your septic line shouldn't freeze. it might even stay a bit warmer than the surrounding. insulate over and if you put up sheetrock just put in a access door for just in case.
 
velvetfoot said:
Precaud,
Aren't there reasons you might have to get into that sill area?
Not in this house - it's a daylight basement so the rim joists are a good 3 feet above ground level.
 
Good luck V, let us know what you end up doing and how it worked.
 
This is what I'm in the process of doing in a basement with a potential water problem and a little radon.

1/8" pressure treated strips on the wall. 4 mil plastic glued over that and then 1" foam glued and taped. Then 2.5" steel studs with 2" foam insulation between the studs. Drywall over everything. The top and corners need some type of fire barrier so fire can't run up the foam into the floor above or the adjacent wall. I'm using strips of drywall. On the base of the new wall I'm using a double height of pressure treated 2x4's. They are glued and screwed to the floor. The reason is that the double height acts as a water dam as well as a good nailing area for the floor trim.
 
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