Wall Insulation in Washington, DC

Wall insulation is easiest to do right when a renovation has the walls open. The DC area sees a lot of gut renovations, rear additions and rowhouse conversions, and that is the moment to get the most out of the exterior walls. Spray foam goes directly into the open stud bays, sealing around wiring, pipes and framing joints as it insulates.

Open walls

Closed-cell foam gives the most R-value in a 2x4 wall and adds air sealing. Open-cell costs less and seals air but has lower R-value per inch. DC's 2017 IECC-based code lists several wall options for new work, including R-13 cavity plus R-10 continuous. Fixr lists foam at $2.75 to $6.50 per square foot in new construction and $3.15 to $7.50 in existing walls.

Closed frame walls

In wood-frame houses with finished walls, we can blow dense-pack cellulose into each cavity through small holes and patch them. HomeGuide lists dense-pack at $1.60 to $4.20 per square foot.

Brick rowhouse walls

Solid masonry walls, common in older rowhouses, have no cavities to fill. Insulating them from inside changes how the brick dries, and needs careful planning. Often the better first step in a brick rowhouse is the roof and basement. We will talk through the options honestly.

Party walls and sound

Open-cell foam in interior walls and between floors can reduce sound transfer. It does not replace a fire-rated party wall assembly, so check with your designer and the permit office for work on a shared wall.

Additions and new construction

New additions in DC, Maryland and Virginia must meet each jurisdiction's current energy code. We install foam to the thickness your designer specifies and can provide written documentation for the inspection.

Coordination

We work with general contractors on renovation schedules, after rough-in inspections and before drywall, and leave the walls ready for the insulation inspection.