What is Insulation?
Types of Insulating Boards
Choose from three types of insulating foam core boards for wall insulation. Products with a higher R-value have a higher cost but have an increased capacity to resist heat flow, and therefore provide greater insulation. Each type comes with unique advantages:
Expanded Polystyrene. Also called Styrofoam insulation, this is the least expensive material. It provides R-values that range from 3.6 to 4.2 per inch. Some products have reinforced facing to make them sturdier.
Extruded Polystyrene. Choose this option for areas that need a good amount of strength and water resistance. It provides about R-5 per inch.
Polyisocyanurate. This material offers the highest R-values—about R-6 to 6.5. Products with foil facing help the panels resist moisture vapor.
Working with Home Insulation Boards
Insulation panels typically come in 4×8-foot sheets. Smaller sizes are also available. They’re much lighter and easier to work with than plywood sheets. Install them using panel adhesive or screws.
For new construction, use rigid boards to insulate slabs and the outside of foundation walls. For a basement remodeling project, consider insulating basement walls with foam board. Use a premade kit for this type of project. Attach the tongue-and-groove insulation boards to the concrete wall with adhesive. Follow with a 2×4 frame wall and insulate it with batt insulation. Keep in mind that any interior rigid insulating panel must be covered by a barrier. A common choice is drywall.
Insulated foam sheets are also used as an insulated sheathing underlayment for exterior siding. The panels provide a continuous energy-efficient surface. This eliminates thermal bridging, which is the energy lost through wall studs. The studs conduct more heat than the insulation between them.
Insulating boards are just one of the many types of foam insulation. Consider using spray foam insulation as well to seal smaller cracks and gaps.