The four gaps every roller door has
A roller door isn't airtight by design — gravity holds the curtain down and the bottom rubber compresses against the concrete. After a few years of summer UV, foot traffic and the door slamming down a few thousand times, the rubber perishes, the side channels bell out, and the top brush wears flat. Result: dust, drafts, water ingress, leaves, and occasionally rodents.
Four targeted fixes restore the seal. All four are DIY-able with basic tools.
Fix 1 — Bottom tropic seal rubber
This is the most important seal and the easiest fix. The bottom slat of every roller door has a continuous channel along its bottom edge that holds a flexible rubber strip — the "tropic seal." After 5–10 years of UV this rubber goes hard, cracks, and stops sealing.
- Measure your door width. Buy a 6m roll of tropic seal in 28mm (most residential) or 38mm (large gap) from a hardware or roller-door supplier — $40–$60.
- Open the door halfway. Look at the bottom edge — you'll see the old rubber wedged in a slot.
- Pull the old rubber out by hand from one end. It'll come out in one continuous strip.
- Cut a new length 50mm longer than the door width. Push one end into the slot from the side, then walk the strip through with your thumb.
- Trim flush. Close the door and check the seal compresses evenly against the concrete.
Fix 2 — Side guide brush strips
The vertical C-channels on either side of the door opening have a 5–10mm gap between the channel wall and the curtain. Self-adhesive nylon brush strip (the kind sold for commercial cold-room doors) cuts this draft significantly.
- Buy 5m of 25mm self-adhesive brush strip — $90–$130 retail.
- Clean both side channels with metho or isopropyl.
- Cut two lengths the height of the door. Peel and stick the brush strip to the inside vertical face of each channel, with the bristles pointing inward to brush against the curtain.
- Close the door and check the bristles compress against the curtain without binding the operation.
Fix 3 — Top brush header
Where the curtain rolls up into the barrel housing there's a gap between the top of the door opening and the curtain itself. A horizontal brush strip across the top of the opening (mounted to the underside of the lintel) brushes against the curtain as it travels and seals this gap.
Use a 50mm wide brush strip with a screw-fixed aluminium backing — about $60–$140 for a residential width. Two stainless screws into the timber or brick lintel and you're done.
Fix 4 — Frame-to-building gaps
Walk outside and look at the join between the door frame and the wall on each side, and the join between the barrel housing and the wall above. Daylight visible? Bead it with neutral-cure silicone (clear or colour-matched). Larger gaps take low-expansion polyurethane foam trimmed flush. $20 in materials.
Threshold seals for water ingress
If your driveway slopes toward the garage and water still gets under after replacing the bottom rubber, install a threshold seal outside the door. Aluminium ramp profiles with rubber lips screw to the concrete in front of the door and create a 10–15mm dam. $80–$150 for a single-door width.
When to call a tech
If the bottom slat itself is bent (won't sit flat on the concrete) or the curtain is no longer running square in the tracks, the seal kit won't fix it — the door needs a track and curtain alignment. Call (07) 4615 4481 and we'll quote the seal kit and any underlying alignment as one job. Most weatherseal callouts under $450 complete.
