SEALING air leaks AROUND WINDOWS AND DOORS

Inspect the spaces around the frames of windows and doors, that is, the space between their frames and the rough openings. Gaps are common in those spaces, causing important drafts and air leakage.

The insulation of the rough opening with common insulation materials doesn’t stop the air flow and possible air leakage (fibrous insulation like fiberglass isn’t an air barrier or air sealant).

See: Weatherstripping windows and doors

Window and exterior door rough openings

Rough openings (namely in windows) are typically 1,5 to 2'' larger than the window frame, to give the installer room to install, plumb and square the window. But that gap is often unproperly sealed, and a cause of air leakage.

Sometimes people think that their air leakage problems is in the windows, when the problem is in the gap between ther frames of their windows and the rough openings.

How to seal deep gaps

Rough Opening Around Windows and DraftsWide gaps in the rough openings can be sealed with polyurethane foam (these liquid foams provide an extremely long-life sealing). Since the gap is typically several inches deep, apply the foam in sucessive layers.

Caulks

Small gaps (less than ½ inch wide) around the frames of windows and doors can be sealed with common caulks.

Some installers also use backer rod between the joints, in case of deeper gaps: the roundness shape of the rod will create a thinner bead and gives flexibility to the caulk; the fact that the caulk doesn't stick to the tbacker rod also allows that extra-flexibility.

Note: Drafts in the movable parts of windows, doors and hatches should be Weather-stripped (not caulked).

Sealing loose panes of glass

Pay also attention the the windows glass panes. If they are loose in their frames, caulk them to avoid air leaking.

In case of wood frames, there are many inexpensive putty compounds and glazing point solutions. For metal and vinyl frames, sealing with vinyl strips is a durable solution.

See also: