Insulating Concrete Block Walls Above Grade

Several types of insulation materials can be placed in the cores of concrete block.

Insulating concrete block walls above grade.

The option for insulating concrete block walls includes spray foam insulation injection foam insulation polystyrene beads foam boards and loose fill masonry insulation. For a below grade block wall see basement perimeter drainage and leaking foundations. While these are the options again the material available to use depends on whether the walls will be covered or the open top is exposed like in a remodel or new build. Above grade perimeter walls built with concrete masonry units or cmus may only represent about 7 of the new home construction market nationwide.

Ideally treat it like a mini basement. Interior insulation refers to insulation applied to the interior side of the concrete masonry as shown in figure 1. The insulation boards are attached with adhesive or with mechanical fasteners. If the floor is concrete slab on grade any furring boards that make contact with the floor must be of treated wood.

After the adhesive cures add extension boxes to the outlets and switches and spray foam into every gap top bottom and around each box. This article deals with a block wall above grade. Leave the floor above it uninsulated vapor seal the ground below with polyethylene and a thin concrete slab insulate the walls with a foam based insulation such as 4 in. Rigid foam board insulation such as polyisocyanurate or expanded or extruded polystyrene are used on the exterior of walls.

He is thinking about stripping it back to the block and then working from the inside to make an insulated wall accepting that he might have to loose a. Bryan is faced with a totally un insulated cinder block wall with 1x2 strapping and a plaster covering. The insulation may be rigid board extruded or expanded polystyrene or polyisocyanurate closed cell spray polyurethane foam cellular glass fibrous batt or fibrous blown in insulation note however that fibrous insulation is susceptible to moisture. Of unfaced expanded polystyrene r 15 that allows the foundation to dry inward and condition the space with air from inside the house.

Standard two by four studs installed flat on the wall provide 1 1 2 inch. Now as you glue the panels to the exposed concrete blocks leave a inch gap at the floor and ceiling and cut holes in the panels to fit around outlets and wall switches.