Fit an automatic door-bottom seal

Fit a drop-down seal to your door's bottom edge to block draughts, working through removal, cutting, fixing, and testing.

DB-01Check your door and buy the right sealWork out what your door is made of: solid timber, hollow timber, composite, or uPVC. Check whether it is a fire door — these are common on flat entrance doors and doors to integral garages, and usually have a coloured plug or label on the top or hinge edge showing a fire rating. Buy an automatic drop-down door seal (also called an automatic door bottom) slightly wider than your door, since you will trim it to fit.

RULES

1 each · Automatic drop-down door seal kit

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KNOW THE RULES

If your door is a certified fire door, only fit a seal tested and certified for fire door use, and keep any smoke seal continuous around the door. Fitting an uncertified seal can invalidate the door's fire rating. This falls under Building Regulations Part B.

DB-02Take the door off its hingesOpen the door and get someone to hold its weight, or wedge it steady. Tap out the hinge pins or unscrew the hinges, then lift the door clear. Lay it flat on a padded surface — an old blanket over a workbench or two trestles — with the bottom edge facing up and easy to reach.

1 each · Screwdriver (flat or Pozi, to match hinge screws)

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1 each · Old blanket or dust sheet

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DB-03Measure the door and cut the seal to lengthMeasure the full width of the door at the bottom edge. Most seals need to sit a few millimetres in from each edge so they clear the door stops when the door closes — check your kit's instructions for the exact gap. Mark the seal's aluminium housing to length and cut it with a hacksaw, then file the cut end smooth so it doesn't snag.

1 each · Tape measure

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1 each · Hacksaw

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1 each · Metal file

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DB-04Position the seal and drill pilot holesHold the cut seal against the bottom edge of the door, centred so the gaps at each end match, and mark the screw hole positions through the housing. On a solid timber door, drill pilot holes about 1mm smaller than the screw shank and only as deep as the screw length, so you don't drill through the face of the door. On a composite or uPVC door, use the self-tapping screws supplied with the kit and a slightly smaller pilot hole, since the core is softer than solid timber.

1 each · Cordless drill/driver

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1 each · Small drill bit (per kit instructions)

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DB-05Screw the seal to the doorFix the seal using the screws supplied with the kit, starting at one end and working along to the other. Snug each screw down but don't overtighten, as this can crack the plastic housing on some kits.

1 pack · Screws (supplied with seal kit)

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DB-06Rehang the door and mark the plunger positionRehang the door on its hinges. Close it gently and check the small plunger pin on the latch end of the seal touches the door frame's stop as the door reaches the closed position. This contact is what triggers the seal to drop. If it doesn't quite touch, you'll adjust it in the next step.

DB-07Test and adjust the dropOpen and close the door several times, watching how the seal drops as the door shuts and lifts as it opens. Use the adjustment screw at the plunger end to fine-tune the drop: the seal should touch the floor or threshold firmly enough to block draughts, but not drag or catch on carpet. Tighten the locknut once you're happy with the setting.

DB-08Tidy up and do a final checkVacuum up metal filings and dust from the door edge and the floor underneath — filings left on carpet can work into fibres and cause rust marks. Check the door still opens, closes and latches properly, and wipe down the seal and surrounding area.

1 each · Vacuum cleaner

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