# Basement XPS installation



## VonTed (Feb 6, 2013)

Looks like I should have posted this here first...... (post in Remodeling forum - opps.)

I am located in NH if that makes any difference.


I think I've got the general idea of sealing the airflow when installing XPS in a basement, but I have a couple of questions on how to handle a few instances.

1. Along the sill, top of concrete walls several wires have been run along there. Can I place the XPS snug against the wires, and caulk, foam the seams to make a seal? (can XPS be placed against wiring).

2. The sewage line runs along the basement wall, most places less then 2" from the wall. I am going to use 2" XPS but it will not fit behind the pipe in all cases. Do I cut above/below and leave a bare concrete gap - caulking the seams? Or hack the XPS as best I can to fit behind the pipe?

3. Similar situation along the floor where the well water pipe and power line runs along the base of the wall. Cut it close, cover the pipes and wiring or go some other route?


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## echonewyork (Feb 7, 2013)

I have the same situation....curious as to what to do as well. Have the same thing going on with the wires...and with the sewer pipes.


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## Rooki (Nov 30, 2011)

*Gaps*

I just had the same issue and here is what I did. 

I ran 2inch XPS up to the top and bottom of all pipes and used spray foam between the pipes and the concrete wall. 
I tried cutting down the 2inch XPS and it was a hassle especially considering every pipe gap was a little different. Much easier to buy cans of spray foam to get that area filled in.

I thought it was important to cover all the concrete with insulation and to get a good air seal. I also wanted to insulate my pipes from the outside concrete to reduce the effect from the cold once the walls are up.


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## batista14 (Mar 25, 2015)

I'm certain you've completed this project as this is an old thread. I just did my basement with 1-1/2" XPS and ran into the same situations in a number of areas. To address the question regarding XPS against wiring. I planned on building an ICF (Insulated Concrete Form) house a few years back and the entire house, outside and inside, is XPS foam. They cut channels in the foam to run all wiring/piping. So it's perfectly safe and within code. 

What I ended up doing was cutting the foam boards to fit as closely to the pipes as possible and am currently going through the dozen spray cans of foam to fill every gap and seal around every seam (I put XPS between joists at the rim joist). What did you guys use for sealing the XPS wall board to the concrete floor? Spray foam or caulking? If caulking.... what kind? Latex, silicon, etc?? Thanks for any feedback.


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## Windows on Wash (Aug 30, 2011)

If the gap is tight, caulking is fine to seal the gap.


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