Concrete insulation is a type of building material used to improve the thermal resistance of concrete walls, floors, ceilings, and foundations. By adding thermal resistance, concrete insulation prevents unwanted outdoor air from entering the home, and keeps expensive heated and cooled air inside. Homeowners with adequate insulation installed in their homes enjoy high levels of energy efficiency, which often results in reduced heating and cooling costs.
Different concrete surfaces in the home offer a number of opportunities to add insulation, either during construction or after. When pouring a new concrete slab, homeowners can add a moisture barrier and a layer of foam insulation between the concrete and the subgrade. If the concrete floor is already in place, one of the best solutions is to add a layer of foam insulation directly to the surface of the concrete, then build a plywood subfloor over top to support the finished floor.
Adding concrete insulation to underground foundation walls and footers helps keep cold underground air from affecting the temperature within the home. Sheets of foam insulation can be fastened directly to these walls to improve thermal resistance. It is also helpful to insulate the interior walls and ceilings of concrete crawl spaces using sheets of rigid foam.
In a concrete block wall, installers often add a layer of insulation on the interior side of the finished wall prior to drywall installation. These rigid foam sheets can also be added to the exterior side of the wall prior to siding installation. For added protection, homeowners can add rigid foam inserts, which fit into the cavities of the block as the wall is built. Once a concrete wall is in place, spray foam offers a chance to add insulation without a major renovation. Installers drill small holes in the wall and inject liquid foam, which quickly expands to fill the entire wall cavity.
One of the most effective forms of concrete insulation requires the use of special insulated concrete forms, or ICFs. ICF panels consist of sheets of rigid foam insulation connected to form a sandwich-type panel. Rather than relying on traditional wooden forms, installers simply pour concrete into the void between the insulated layers of the ICF. ICF panels can be used to construct any concrete surface, including walls, floors, and ceilings.
When choosing concrete insulation, homeowners should first consider the type of access available for installation. The chosen material must be capable of resisting moisture, pests, fire and other factors. It should also be easy to secure to the applicable area. For example, insulating blankets may not hold up well under a concrete slab on grade, but may offer an effective choice for insulating a crawl space ceiling.