Introduction to Weatherstripping

Drafts around the doors and windows of a home can cause unpleasant temperatures in the house along with significantly raising heating and cooling costs. Most air leakage in any particular house is found in the cracks around the doors and windows, and can be sealed with weatherstripping. Weatherstripping these cracks can actually reduce heating and air conditioning costs by as much as 30 percent.

Some houses have grooved window sashes and doors which interlock with metal flanges around the window and door frames. This type of built-in weatherstripping is convenient when it comes preinstalled, but it is easy to install weatherstripping in homes that are without it. If drafts can be felt around windows and doors on a windy or cold day, or if light can be seen through cracks around the doors or windows at night, weatherstripping should be installed.

There are many types of weatherstripping materials. Flexible rolls of felt, metal, plastic foam, rubber, or vinyl weatherstripping are useful for both doors and windows. Rigid weatherstripping strips edged with plastic, foam, or felt are good for the sides and tops of doors, and various thresholds, sweeps, and seals can be purchased for the bottom of doors.

For double-hung windows, the best and most easily hung form of weatherstripping is a springy metal stripping. This type of weatherstripping should only be nailed along one edge, as the other edge springs out to block the leaks. It is installed in a way that it is invisible when the window is shut.

Casement and gliding windows are slightly more difficult to seal. For metal casement windows, a special grooved vinyl gasket should be used. First, an adhesive is applied to the window frame, then the vinyl gasket is positioned so that the window closes against the flat side of the stripping. Wooden casement windows often have built-in weatherstripping, but if they don't, spring metal stripping — the same used for double-hung windows — can be installed.

Gliding windows often have weatherstripping built in between the sash and the frame. If there is no weatherstripping, it should be installed. If both sashes on a window move, it can be treated as a sideways double-hung window. If there is only one gliding sash, only the movable part of the window should be treated. Spring metal can be installed in the side that receives the sash. Vinyl or rubber gaskets should then be added to the other edges of the gliding sash.

Doors are a major cause of air leaks. Before installing weatherstripping, the door must fit properly. Hinges may need to be adjusted and edges sanded before weatherstripping can be installed. There should be a narrow but uniform space between the door edge and the jamb, and the door should open and close smoothly.

The sides and top of the door should be fitted with a form of rigid weatherstripping. Common types are adhesive-backed foam, a V-strip made of springy metal, plastic tubing, or foam-edged wood. The bottom of the door must be sealed differently, and is the most difficult part of the door to seal.

The bottom of the door can be fitted with a "sweep," a form of weatherstripping which drags a flexible strip against the threshold. Some special weatherproof thresholds can be installed to press material up against the bottom edge of the door for a tighter seal.

Weatherproofing is not a daunting task, and can be installed fairly easily once doors and windows are straightened and measured, and the correct weatherstripping material is purchased.