How to Install Foam Board Insulation
Foam board insulation can be bought in a few different types. The type you choose will depend on the R-value you require and where you install it. The least expensive of the boards is called MEPS. It has the lowest R-value and is a little difficult to work with because it warps and chips very easily. XEPS is a higher-density foam board and easier to work with. It has a higher R-value per inch and doesn't absorb moisture as quickly. Many municipalities have regulations on how this insulation is to be installed, both for moisture and fire issues. Make sure you check with your local building code office before installation. Does this Spark an idea?
Things You'll Need
- XEPS foam insulation boards
- Construction adhesive
- 2-by-2 inch wood boards
- 2-by-3 inch wood boards
- Framing nails
- Vapor barrier
- Utility knife
Instructions
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1
Frame out a basement wall. Foam board insulation is flammable and must be covered with drywall or some other covering. So if you're installing on a basement or other wall with no framing, you'll have to frame the wall to install the outer covering. Use 2 by 3s for the plates and 2 by 2s for the studs. Make the studs 24 inches apart. Use three 8-foot 2-by-3 inch boards for a 10-foot wall. The plates will need to be cut and are installed at the top and bottom of the wall; the studs are vertically installed between the plates. You'll need five 8-foot studs for a 10-foot wall.
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2
Cut the foam board by scoring it with a utility knife, bending it and then cut through. Cut pieces to fit between your studs.
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3
Use construction adhesive to attach the boards to the cement walls. Don't nail the boards, as any holes in the boards will reduce the R-value and make it less effective.
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4
Cover with a vapor barrier. Foam boards will absorb moisture and can create mold problems if not kept from the moisture. A common vapor barrier is thick plastic sheeting stapled to the studs. Vapor barriers are normally installed on the inside of the wall, but if you live in a very hot climate, check with your local building code office to see if this is best for you.
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5
Cover your walls with drywall or paneling.
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Tips & Warnings
Do not allow the foam board to sit in the sun prior to installation. This will reduce the R-value and make the insulation less effective.
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Comments
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Please let me ask why do you use XPS and why you don't use EPS instead?
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jackoalltrades9
Nov 06, 2009
You said, "Make the studs 24 inches apart", but isn't the national code 16 inches apart? On a side note, I found that cutting the foam board with a sharp pocketknife held at a slight angle worked better than a utility knife, which tended to catch large pieces of foam...
