A garage door is a big moving panel in a frame that is rarely perfectly square, so gaps are inevitable. They let in rain, leaves, dust, draughts and sometimes small animals. You can close all of them with two types of seal.
The three gaps
- The floor gap under the door. Rain and leaves enter here.
- The side gaps between the door edge and the frame.
- The head gap along the top of the door.
Step 1: seal the floor
A rubber threshold seal is a raised strip stuck to the floor at the base of the door. The door closes onto it.
- Measure the width of the opening and choose a strip at least that long. A single door is about 2.1m, a double door 4.2m to 4.8m.
- Check the gap height at several points. A taller threshold suits a bigger gap or a sloping floor.
- Prepare the floor. Sweep, scrub with a stiff brush, remove oil and old sealant, and let it dry completely.
- Dry-fit the strip and close the door to check it seats properly.
- Glue and weigh. Apply a suitable outdoor adhesive, press the strip down, and weigh it down for 24 hours.
Step 2: seal the sides and top
A brush-pile strip is stuck or screwed to the frame so the bristles brush against the door. It closes narrow, uneven gaps without stopping the door. Measure the side and top lengths and add them together. Seven metres is enough for a single door.
Common mistakes
- Gluing to a damp or dusty floor, which stops the adhesive from taking.
- Choosing a threshold that is too tall for the door's travel, so the door cannot close.
- Not leaving the adhesive to cure before driving over it or closing the door hard.
- Sealing a garage that houses a boiler or a gas appliance without checking ventilation. Keep any air vents clear.
Combining with an internal door
If the garage has a door into the house, draught-proof that door as well, with a door bottom seal and a strip around the frame.