The Best Insulation Material for a Cold Concrete Block Wall in the Basement

Blanket Insulation

• You could install the same type of insulation you use in the rest of your house in the basement, but only if you are confident that the basement will stay dry. Fiberglass rolls and batts supply up to R-3.8 in insulation performance, but they lose those qualities when they become wet. If the home was constructed with first-rate exterior waterproofing, you may not need to take any additional steps. Otherwise, you must first apply an interior waterproofer to your concrete block wall. Before choosing fiberglass rolls, you should also check out the new generation of cotton insulation rolls because they are itch-free, painless to install, and are pretreated for both mold resistance and fire resistance.

Rigid Insulation Panels

• Rigid lightweight panels constructed of expanded polystyrene can deliver insulation values of up to R-4.4 per inch. EPS panels can be glued directly to any waterproofed concrete block wall with a mastic adhesive. Panels should be fitted as closely together as possible, and the gaps should be caulked and taped.

Sprayed Foam Insulation

• A big advantage of spray foam insulation is that it can be applied directly to the concrete block wall, or it can be used to fill the space behind an existing drywall installation. A polyisocyanurate or polyurethane foam forms an air-resistant barrier that can provide insulating values of between R-7 and R-9 per inch. Foam insulation is usually applied by professional installers, but it is also possible to rent the necessary spraying equipment.

Loose-Fill Insulation

• Loose-fill insulation can be blown into existing wall cavities behind drywall, which makes it ideal for basement areas that have already been finished but not properly insulated. If the drywall is not already in place, loose-fill insulation can be blown behind a vapor-retarding membrane. Loose-fill materials suitable for basement walls include cellulose and stabilized cellulose. Cellulose insulation can provide insulating values of up to R-3.8 per inch. Stabilized cellulose contains a low level of moisture and adhesive that will position it permanently to a properly waterproofed concrete block wall. Cellulose insulation is made from recycled newspaper, and it has been chemically treated to guarantee resistance to mold and fire.