Insualtion question (1 Viewer)

[Tim L]

I am in the process of insulating my romm which was previously a garage- my question is one of the walls had to be framed with 2x3 studs because of an adjoing door entrance into the house- can I use the same insualtion I used ont he 2x4 walls (R-13 faced)but just trim a little off the thickness off the insualtion pieces to make it fit better in the 2x3 bays instead of trying to stuff the whole thing in- which I believe will be counterproductive in theinsualtion properties because of the lack of air-pocket betweent he cement wall and the fiberglass insualtion- any advice appreciated. I thought this would be easier than cutting foam insualtion pioeces and them putting up my own poly vapor barrier- thanks in advance
Tim

 

[Dave Farley]

It might be difficult to actually trim some of the thickness from the insulation. If you can, go for it. You don't want to stuff it in. Compressing it does cause a loss of R-value. If this is an interior wall between the garage and the inside of the house, you might want to call an insulation contractor in the yellow pages just to ask them about using faced insulation in an interior wall. I've always heard that you shouldn't. Other options:

-Foam sheets

-Blow in cellulose insulation after installing drywall

-Expanding foam insulation-there are companies that do this.

 

[Marc_Sulinski]

I think that you will find it extremely difficult to trim layers off the insulation. I don't think it is meant to be cut in that direction. What is likely to happen is that it will get all chopped up and be very uneven, and you will end up with pieces of fiberglass in your skin.

Maybe they make thinner insulation meant specifically for applications like yours. If not, I would suggest foam.

 

[DonnyD]

Been around the building business all my life and I've never heard that compressing insulation decreases the r- value and effectiveness of its insulation.
Personally, I'd compress it.........paper faced is fine for your wall application.

If you've noticed any condensate on the cement walls where you intend to insulate, you may need to consider a moisture blocking coating ( the kind used for basements sometimes) for the cement prior to adding insulation.........

 

[Dave Farley]

If you compress insulation to fit in a wall space that is smaller than what the insulation is intended for, you will only get the R-Value that you would get from insulation of the proper thickness. That's what I meant by a loss in R-Value.

In other words, a 2X4 wall calls for R-13 insulation, which is 3.5" thick. Stuffing in R-19 insulation, which is 6.25" thick and intended for 2X6 walls, will not give you R-19. You will still only have around R-13, thus causing a loss of R-Value if you use an R-19 batt.


http://www.owenscorning.com/around/i...n/faq_wall.asp


Tim,

If the wall you are talking about is a wall between the kitchen and the attached garage, make sure the vapor barrier is facing the kitchen. It's intention is to keep the moisture from the inside of the home from migrating to outside walls and condensing there. When insulating interior walls(between bedrooms, etc.), go with unfaced insulation.


From Owens-Corning website:

" In the winter, any moisture that passes through to these surfaces can accumulate and condense on the cold inner sides of exterior surfaces. Eventually, this condensation may blister the outside paint, form stains on drywall ceilings or walls, or even damage your house structure.

Whatever vapor retarder you choose, remember this important rule of thumb: In heating climates, the vapor retarder is always installed toward the warm-in-winter side (living area) of the house.

(In the Gulf Coast and Florida, local building practice may not call for an interior vapor retarder, or may call for the vapor retarder to be installed toward the outside in exterior walls. See installation instructions on package."

 

[Jim_F]

I'm all for the foamboard type. I have fiberglass in my detached garage and the mice LOVE it.