Basement insulation

[Arc_Dad]

I can get 1 1/4" sheets of foam insulation for $10. Should I go w/ them or spend more on 2"?

 

[Arc_Dad]

It's to put on the interior of my basement walls.

 

[Beetle-Kill]

What's the R-value?

 

[gpcollen1]

R-value is really the most important. Along with that, you want XPS. Here is what i am using, available at Lowes for $17 a sheet.

http://www.lowes.com/pd_14542-46086-121071_4294858106_4294937087_?productId=3013692&Ns=p_product_prd_lis_ord_nbr|0||p_product_quantity_sold|1&pl=1&currentURL;=/pl_Insulated+Sheathing_4294858106_4294937087_?Ns=p_product_prd_lis_ord_nbr|0||p_product_quantity_sold|1

Make sure you read this too...along with the other articles on basements and insulation...

http://www.buildingscience.com/docu...nderstanding-basements/?searchterm=insulation

 

[livefreeordie]

I can get 1 1/4" sheets of foam insulation for $10. Should I go w/ them or spend more on 2"?

I used the 1" foam on my walls and the temp has not been below 50 since then. Before it would be around 40 when the outside temp was in the single digits. Well worth the money. 1 1/4 for $10 is a good price.

Here is a thread i started about insulating the walls

https://www.hearth.com/econtent/index.php/forums/viewthread/66548/

 

[LLigetfa]

I can get 1 1/4" sheets of foam insulation for $10. Should I go w/ them or spend more on 2"?

What size are the sheets? How much more for 2 inch? If two layers of 1 1/4" is cheaper than one layer of 2", just double it up.

I have a 2x6 PWF with R22 fibreglass between the studs and another 2 inches of rigid foam panel on the outside. the 4x8 panels were around $40 at the time.

 

[Arc_Dad]

I went and checked it out yesterday. It's at a salvage store called Marden's. It is in good condition, but appears to be covered w/ paper instead of foil. The foam itself is a pale yellow color and there is no writings on any of it. I think the paper going directly onto the concrete walls is a deal breaker, but am very interested in your ideas. Thanks for the input.

 

[LLigetfa]

Ja, you should never put paper close to concrete or in any high humidity location as it promotes mold growth.

 

[midwestcoast]

Sounds like it's the Poly-Iso-Cyanurate (SP?) board? If so it's not so good for below grade applications as it absorbs water. As CTWoodburner says, best to use XPS to reduce issues from moisture.

 

[dave11]

You wouldn't want paper, or foil, against the walls. Condensation will form on the inner surface of the wall.

You need to use vapor-permeable stuff, like the pink Owens-Corning or the green Pactiv stuff, or similar.

 

[bogydave]

It's to put on the interior of my basement walls.

I had an "energy audit". The guy told me to put 2" of blue board insulation on the outside.
I dug down 2' & put it all the way around the foundation.
Looks like the same stuff, closed cell so it won't absorb water. supposed to last forever.

 

[gpcollen1]

I went and checked it out yesterday. It's at a salvage store called Marden's. It is in good condition, but appears to be covered w/ paper instead of foil. The foam itself is a pale yellow color and there is no writings on any of it. I think the paper going directly onto the concrete walls is a deal breaker, but am very interested in your ideas. Thanks for the input.

Read the Building Science Articles..

http://www.buildingscience.com/docu...nderstanding-basements/?searchterm=insulation

Use XPS for the walls - the DOW stuff is blue.

 

[bogydave]

Very good "insulation" article.