Extruded Polystyrene Insualtion Layers

[njbadboy]

Hello all....a friend of mine is remodeling/adding on to his house and under the vinyl siding the homeowner installed DOW XPS(Blue) Foam, which was over cedar siding. The insulation board is 3/4" tongue and groove, and since my is ripping everything off, I'm have and will be taking the insulation board.

I have already framed out my barn (30'x32') with 2x4's 16"OC and will be insulating with R19 fiberglass insulation this fall. I have it that the fiberglass will by kept off the outside wall about 1 1/2".

Now that I have been give the XPS, I would like to insulate in between the girts, and if I double layered them, they would be 1 1/2", and even with the girts.

Has anyone double layered the XPS boards or know that it is acceptable to do so?

I will still be adding fiberglass insulation this fall, figure I just use the XPS to keep it out of the dump and get some additional R value.

Thanks for any help!

Jeff

 

[njbadboy]

Thanks for all the help, but I got a return email from DOW and they advised that it was acceptable to layer them...... in case anyone else needs the info.

 

[Steve in Mi]

FWIW, There may be a better place for the rigid foam depending on your plans to heat this structure and insulate below grade.

Layering is not only acceptable, it can be a plus when staggering joints on adjacent layers.

 

[njbadboy]

I already have it under concrete slab. This was extra that I put up prior to fiberglass rolls in between studded wall.

 

[Steve in Mi]

How much insulation do you have at the outside edge of your slab?

 

[njbadboy]

About an inch to an inch an a quarter. I was pressed for time and thats all I could do at the time and ran XPS R5 or R10 under slab, which is built upon 52 stones of crushed concrete.

 

[rburke65]

Ok....I'll bite.....what is "52 stones" of Crushed concrete? Thanks.