[claybasement]

ok, here's my first post about my finished basement project. I'm past the framing, electrical, media closet is almost done so now I'm down to running speaker wires and then to insulation. I know this ventures off a bit from the HT topic, but my question is what is the best method to insulating my outer walls of my basement? I've heard so many conflicting methods and can't decide on one. All my outer walls are set one inch from the concrete wall and I live in Indiana so we have all the seasons here so my main concern is moisture. Any ideas? Thanks, Ned

 

[WestCDA]

Finished walls that are affixed one inch from your concrete walls isn't much. In Indiana I would expect you have some relatively cold temperatures in the winter time, and you won't get much of an R value in a one inch space - unless you mean you have conventional 2 x 4 framing that is 1 inch from the concrete. If that is the case, you can get batts of insulation at any home improvement store sized to stuff in the framing cavities.

In addition to insulation you will need a vapour barrier - what is your local building code for exterior walls? It will specify the details such as location of the barrier relative to the insulation for your climate, as well as the plastic thickness required to meet code.

 

[White fish]

I guess you mean 1" then 2x4 or 2x6 studs?
giving you 4 1/2 or 6 1/2 space to fill

I put roofing tar paper against the concrete so my batt wouldn't wick any water it to it

 

[beanagee1]

I am just getting my basement done. My architect/contractor had foam insulation blown in. He tells me that it acts as vapour barrier, and it is best insulation that money can buy. It also happens to be the most expensive type.

 

[lastyear4gt]

I went with a 1 inch styrofoam glued to the concrete wall and then tuck taped the seams and then studed. Makes for a great vapor barier. Just use 2X4 construction bat insulation with a good R value. I recommend Roxul.

 

[BlazeHemi]

I glued 1 inch foam to the concret walls as well then built a 2x6 wall using 2x4 for the middle studs and 2x6 for the header and floor board then filled that with roxul for a 2x6 wall for a finished R-value of 28. The foam I used is open cell foam so I still needed a vapour barrier. If your budget allows spray foam is the way to go.

Greg

 

[White fish]

lastyear
dont you want vapor barrier on the warm side?
do you put 6mil under your drywall?

 

[mateo_f4]

+1 to sprayfoam

 

[claybasement]

When I built the walls I used 2x4's and I came out about 1 inch from the concrete wall because I read somewhere that allowing air flow behind the wall to dry the moisture is the best bet. I hear some people doing the vapor barrier and some people not so I'm not sure what method to go with. I may go with the rolled bats, but the vapor barrier is what I'm confused on because seems like I'm reading several places that it's almost better not putting a vapor barrier since air will get behind the walls regardless and more focusing on making sure you have enough space for air flow so the moisture can dry. Thanks for the ideas.

 

[WestCDA]

Your local building code will settle the question for you - it will state whether a vapour barrier is required, what material is acceptable if it is, and what side of the framing/insulation it needs to be installed on for your climate. Why guess?

 

[Dwayne Gorniak]

Guys, here is a great link from the Canadian Government website on some standards for insulating basements. There is a allot of info on this site so you'll have some reading to do. Enjoy: http://www.oee.nrcan.gc.ca/resident...on-sealing/basement/khi-inbasement.cfm?attr=4

 

[dgb]

FYI - spray foam and cabling.

I just had my basement spray foamed. 3 days later, I had Eastlink come in to replace the cable that was run inside an outside wall of the house from the basement to the first floor. The cable was embedded in the spray foam when the space above the concrete along the rim joist was sprayed.

The Eastlink tech said it was the third house he has been to where the spray foam had crushed the coax enough to impede the signal.

I was able to drill a hole in the floor against the baseboard to run a new wire through. This weekend I'll be removing the coax plate from the wall and patching the vapor barrier and drywall.

 

[DLPAddict]

In the process of insulating my basement (80% done) and replaced the windows 5 of them.

What I did was built stud wall all around the exterior wall with 2"x4" spaced at 16" (center to center) and use Roxul insulation easy to cut and less itchy than the pink stuff
Sealed off hard to reach area with spray foam (expanding spray foam in a can)

On top I put vapor barrier and will cover it with dry-wall for most wall not sure yet about the HT room might go with dry-wall and different paneling for look and texture.

I can already feel a difference the temperature is more stable and the humidity is steady around 50-60%.

The beauty with Roxul is waterproof and fire retardant.

The stuff is made with some kind of stone don't know about the process but it's working.

 

[Kaoru]

My outer basement walls...

I just finished insulating my basement. As mentioned there is a lot of way to do this and some of those ways depend on the application/context. Spray foam is the best way to go but it has downsides; it's expensive and you have to fire rate any exposed foam (ie. drywall or spray fire retardant). Upside is no vapor barrier needed and you don't have to worry about moisture build up.

Besides spray foam, no other method will perfectly seal vapor or stop moisture build-up. When you insulate using other methods, there are four things that are a must: 1) moisture barrier, 2) insulation, 3) vapor barrier, and 4) breathing/venting. Most handle the first three but forget the fourth. Moisture/vapor WILL build up *behind* the vapor barrier because no seal is perfect and if moisture/vapor has no where to go, mold/water damage will result. In my basement I left the concrete bare at grade and above; i.e. no moisture barrier, tar paper, or glued on rigid foam above grade. Why? Because the bare concrete breaths above grade to the outside. I got this tidbit of info from the NRC. Of course I still put in insulation (not touching the concrete) all the way into between the floor joists, then VB tuck taped everywhere. Hope this helps, you can read my thread for info or for pics.

Cheers,
Kaoru

 

[therealjoeblow]

Your local building code will settle the question for you - it will state whether a vapour barrier is required, what material is acceptable if it is, and what side of the framing/insulation it needs to be installed on for your climate. Why guess?

+1 on that

I never understand why handymen who don't really know what they're doing ask other similar folks for advice that can affect their insurance, health, and future resale value (or even saleability) of their houses.

CHECK YOUR CODE, and ask a local building inspector for advice.

Cheers
The REAL Joe