Window and Door Weatherstripping: Types, Installation, and Replacement

Finding the Drafts

Hold a lit incense stick or a thin piece of tissue near window and door edges on a windy day. The smoke or tissue deflects where air is leaking in.

Common leak points: the bottom of exterior doors (worn sweep), the sides where double-hung window sashes meet the frame (worn V-strip or spring bronze), the meeting rail where upper and lower sashes overlap, and around door frames where the weatherstrip compresses against the stop.

Check the threshold under exterior doors. If you can see daylight between the door bottom and the threshold, the sweep or threshold is worn.

Types of Weatherstripping

V-strip (tension seal): metal or plastic folded into a V shape. Springs open to fill gaps. Most durable option for window channels. Lasts 5+ years. Harder to install but stays put.

Adhesive-backed foam tape: cheapest and easiest to apply. Peel and stick. Compresses to fill gaps. Degrades in 1-3 years depending on sun exposure and how often the window or door opens. Fine for windows you rarely open.

Tubular rubber or silicone: a rubber bulb attached to a wood or metal flange. Nails or screws to the frame. Good for doors. Lasts 3-5 years. Visible when the door is open.

Door sweeps: a flat strip that screws to the bottom of the door and has a rubber or brush fin that seals against the threshold. Easy to install and replace. The most common fix for under-door drafts.

Interlocking metal: two pieces of shaped metal that hook together when the door or window closes. Most weathertight and most durable. Requires precise installation — usually professional.

Window Weatherstripping Installation

For double-hung windows, V-strip along the side channels works best. Open the window fully. Clean the channel with a stiff brush and wipe with rubbing alcohol so adhesive sticks.

Cut the V-strip to length. Peel the adhesive backing and press it into the channel with the V opening facing outdoors. The strip should be just snug enough that the sash slides with slight friction — not so tight that you cannot open the window.

For the meeting rail (where the two sashes overlap), apply foam tape to the bottom of the upper sash where it contacts the top of the lower sash. This is the hardest seal to get right on a double-hung window.

Casement windows are easier — apply foam tape or tubular rubber to the frame where the sash presses against it when closed. Clean the surface first. Close the window and check that the compression is even all around.

Door Weatherstripping Installation

For the door sweep: close the door. Hold the sweep against the inside face of the door so the rubber fin just touches the threshold. Mark the screw holes. Drill pilot holes and screw it in.

For the sides and top: measure each piece of the door stop. Cut tubular rubber weatherstripping to length. Nail or screw the flange to the stop so the rubber bulb compresses against the closed door face. The bulb should flatten about 1/3 when the door is closed — enough to seal but not so much that the door is hard to close.

Self-adhesive foam works for the sides and top of doors you do not use frequently. For daily-use exterior doors, use mechanically fastened weatherstripping — adhesive fails faster with repeated impact.

Tools and Materials

Utility knife and scissors for cutting weatherstripping. Tape measure. Rubbing alcohol and rags for surface prep. Hammer and brads for tubular rubber flange. Drill and small bits for door sweeps. Tin snips for metal V-strip.

Buy 10% more material than your measurements call for. Weatherstripping is cheap and running short mid-project means a second trip to the store.

Frequently Asked Questions