Sealing door draughts before the cold hits
Door weatherstripping is a compressible or flexible seal fitted around the frame, the bottom and the threshold so that the door closes tight. It is one of the cheapest ways to cut winter draughts, takes an hour or two, and usually needs replacing every few years as the material hardens or flattens.
How do you tell if a door leaks?
Start with the obvious. On a windy day, hold the back of your hand or a stick of incense around the edges and watch for movement of the smoke. Then try a light test: have someone shine a torch from outside at night while you look for glints of light around the closed door. A sheet of paper or a banknote trapped in the closed door should resist when you pull it. Where it slides out easily, the seal is weak. A blower door test finds leaks across the whole house, as described in our air tightness guide.
What types of weatherstripping are there?
- Self-adhesive foam tape. Cheap and quick, good for small, even gaps, but it wears out fast.
- V-strip (tension seal). Folded metal or plastic that springs against the door, durable and good for the sides of the frame.
- Rubber or silicone bulb seal. Fitted into a groove or a kerf cut in the frame, and long-lasting.
- Magnetic strips. Used on steel doors, closing tightly against the metal.
- Door sweeps and thresholds. Fixed to the bottom of the door or the floor, and adjustable for uneven gaps.
Match the product to the gap size and the door material. Wood and fibreglass doors take most types, while steel doors often use magnetic or compression strips.
How do you replace door weatherstripping?
Remove the old material fully, scraping off adhesive and cleaning the surface so the new strip bonds. Measure each side, cut the strip slightly long and fit it along the frame stop so that the closed door compresses it lightly. Too much compression makes the door hard to latch, and too little leaves gaps. Fit the sweep or threshold last and set its height so that it just brushes the floor. If the latch will not engage, adjust the strike plate or the hinges before you add more material. Hinge screws that have loosened can tilt the door and create a gap that no seal can fill.
What about the threshold, mail slot and storm door?
The bottom edge of an entry door is the usual weak spot. An adjustable threshold lets you raise it as the door settles. Mail slots can be fitted with a flap or a cover, and a letter box on an outside wall gives a way to remove the opening altogether. Storm doors add a second line of defence and some insulation but must vent properly in sunny weather. If the door itself is warped, thin or rotten, replacing it may beat fixing the seal. A well-sealed, insulated door fits the broader sequence in the upgrade priorities guide.
Is there anything to be careful about?
Do not seal air supply for fuel-burning appliances, and keep working carbon monoxide alarms on each level. Draughts can be a sign that a house is leaky overall, so look at the rest of the envelope with the methods in air sealing a house. The same attention applies to windows, which can be re-caulked or replaced as covered in energy efficient window replacement. For a short seasonal list, see the winter home energy checklist. Seal costs are low and vary by product and retailer, so compare price per metre and expected life, not just the shelf price.
Quick answers
How often should I replace door weatherstripping?
Many seals last a few years, and longer for good silicone or metal types. Replace them when they are flat, cracked, hardened or letting in light.
Can I weatherstrip a door myself?
Yes. It needs a tape measure, scissors or a saw for the stop, and a screwdriver, and most owners finish in an hour or two.
Will weatherstripping stop all draughts?
It stops those that come through the door gap. Draughts through the wall, outlets or the frame itself need other sealing.