Garage & Bonus Room Insulation in Worcester, MA

Garage and bonus room insulation fixes a problem common in colonials and newer homes in towns like Shrewsbury, Westborough and Northborough: a bedroom or bonus room built over an attached garage. That room has cold air below its floor, often a kneewall or sloped ceiling above, and outside walls on two or three sides. Even with batts in the floor, it is usually the coldest room in winter and the hottest in summer.

Why batts fall short

Fiberglass batts in a garage ceiling often sag, leave gaps at the rim, and do nothing to stop air moving through the floor framing. Garage air carries exhaust and fumes, and those can reach the room above through the same gaps. Spray foam in the floor bays fills the space, sticks to the subfloor and seals the edges. Closed-cell gives the most R-value in shallow joists; open-cell can fill deeper bays for less.

Kneewalls and sloped ceilings

Bonus rooms often have short kneewalls with attic space behind them, the same layout as a Cape upstairs. Air moves freely from that side attic into the floor framing of the room. We seal those joist bays, insulate the kneewall or the roofline, and make sure the floor and walls form one continuous barrier.

Insulating the garage itself

Some homeowners want a heated workshop or a garage that stays above freezing. Foam on garage walls and ceiling makes it practical to heat. Fire separation between the garage and the house matters here; exposed foam generally needs a thermal barrier like drywall, so we explain what your space needs before quoting.

Detached garages and shops

For detached garages and small outbuildings, closed-cell foam on the walls and roof deck seals and insulates in one step and stops condensation dripping from cold metal roofing. We price these by the square foot of surface sprayed.