Basement Insulation using Rigid Foam Insulation

Keep your Finished Basement Warm by installing Rigid Foam Insulation

By Mark J. Donovan

When planning to finish a basement, it is important to consider the installation of basement insulation. One of the best types of basement insulation to install is rigid foam insulation. Rigid foam insulation will help reduce the heat conduction from the warm basement living area to the cold foundation walls. Depending upon the brand, rigid foam insulation has an R-value between R-4 and R-8 per inch of thickness.

Rigid foam insulation is made from extruded polystyrene, polyisocyanurate and polyurethane. It is ideal for a variety of applications including the insulation of basement walls. It can be used on both the interior and exterior of basement foundation walls.

Rigid foam insulation comes in a variety of widths, heights and depths. It is particular ideal for basement insulation projects due to the fact that it is waterproof. The only real down side of rigid foam insulation is that it is subject to insect infestation and damage. Thus a homeowner needs to be on the alert for carpenter ants or termites in the home.

Installation of Rigid Foam Insulation in Basement

Rigid foam insulation is easy to install in the basement. Typically it is cut to size with a carpenter’s knife or a saw and squeezed into place between the furring strips. It can also be glued onto the basement foundation walls if it was loose-fit cut.

Before installing rigid foam insulation it is important to make sure your basement walls do not have a moisture problem. It is also a good idea to use a water sealer on the inside basement walls prior to installing the furring strips and insulation.

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Note that furring strips are typically used in finishing basements. The furring strips are fastened to the basement foundation walls so that drywall can be hung on them. Rigid foam insulation can then be installed in-between these furring strips prior to hanging the drywall. Usually the furring strips are attached to the concrete basement foundation walls on 16” or 24” centers.

After the rigid foam insulation has been installed between furring strips, a sheet of 6 mil polyethylene plastic should be stapled over top of it. The plastic forms a vapor barrier for the insulation. Once the vapor barrier has been attached to the furring strips you can then proceed to install drywall or paneling.

Rigid foam insulation can also be used on the exterior basement walls; however it is more susceptible to insects when used this way. Insects won’t eat the foam, however they can bore tunnels through it and as a result it may become a conduit for insect home infestation.

Rigid foam insulation for basement walls

Also, never use rigid foam insulation around furnace areas or other hot areas without using a fire barrier over it. Rigid foam is flammable and can emit toxic gases if ignited. Before installing rigid foam insulation around furnace areas, you may want to check with your local building inspector. In addition, after you complete the basement insulation phase of your basement remodeling project, you will need to get an inspection.

For more help on Basement Additions, see’s Basement Remodeling Bid sheet. The Basement Remodeling Bid Sheet will help ensure that your hire the right contractor so that your basement remodeling project is done correctly and you get the project finished on time and budget.

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