Is foam board good for basement walls?

XPS foam boards are naturally semi-permeable, which makes them a common insulation material for basement walls. It uses recyclable materials in manufacturing and is available in faced and unfaced versions. Its special properties make it a vapor retarder but not a vapor barrier.

Can you put foam board over concrete?

There are several ways to install subflooring above the rigid foam: you can use either one or two layers of plywood or OSB, and the subflooring can either be fastened to the concrete with long Tapcon screws or it can simply float above the foam.

Does XPS insulation need a vapor barrier?

XPS is manufactured in both an unfaced form or with different plastic facings. However, XPS is considered a vapor retarder, not a vapor barrier….Privacy Overview.

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What kind of insulation is best for basement walls?

Rigid foam sheets are best for DIYers who are insulating basements prior to framing the walls. Rigid foam also works well when the concrete or block walls are smooth and flat. Rigid foam insulation is easy to use. In addition to scoring, it can be cut by an ordinary wood saw.

Does XPS absorb water?

Independent research2 has shown that over time XPS will actually absorb and retain more moisture than EPS resulting in a significant decrease in R-value. One of the studies showed XPS retained 19% water absorption compared to 5% for EPS after being buried below grade for 15 years.

Is XPS foam permeable?

Any product with a perm rating greater than 10 is highly permeable and is not considered a vapor retarder. Unfaced 25-mm (1-in.) thick XPS has a perm rating around 1, and is measured as semipermeable.

Is XPS vapor permeable?

Therefore, 1 inch of XPS is considered to be vapor semi-permeable, while 2 inches is considered to be vapor semi-impermeable.

Can you install foam board directly against basement walls?

Can you install foam boards directly against basement walls? I read in one of your articles when putting up rigid foam to Install two inches of rigid insulation board directly against concrete. A mold expert told me to put the board on top of the framing, not directly onto the concrete wall so the house can breath.

Can Mold grow on XPS foam board?

XPS foam board is a closed cell product that will not absorb water and is considered a vapor barrier when a minimum thickness of 1-1/2″ is used. For mold to grow you need warm temperatures, water and food. Neither foam nor concrete are food sources for mold, thus no mold in that space.

Should I use EPs or XPS to insulate my basement?

Brad, First of all, as I explained in my article, How to Insulate a Basement Wall, any basement that suffers from water-entry problems is not a candidate for interior insulation or finish work. I don’t care whether you use XPS or EPS, if you get water entry, you’ve got a problem — and you don’t want drywall or finish flooring in your basement.

What color foam board should I use in a basement?

I prefer a closed cell blue board (or pink). You can also use foil faced polyiso. I have a framed out basement in North Dakota the walls are all in place with no foam board behind them. Can I just put foam board up in between the studs?