A draughty uPVC door is one of the most common calls a fitter gets in autumn, and one of the cheapest to actually resolve — when the seal really is the problem. It often isn’t. Seals get blamed for draughts that are actually coming from a dropped door, a worn mechanism, or a frame that’s shifted, and swapping a seal that wasn’t the fault fixes nothing except the bill. Knowing which one you’re looking at takes about two minutes and saves a lot of wasted effort.
Key Takeaways
- uPVC door seals typically last 15 to 20 years on a well-made door before UV and repeated compression wear them out.
- A hardened, flattened or cracked seal that’s lost its bounce needs replacing; a soft, springy seal is not your draught source.
- Replacement seal is genuinely low cost, sold by the metre as a market range, and matching the profile correctly matters more than the brand.
- A draught that persists after a seal replacement almost always means misalignment, a worn mechanism, or a failed glazing bead — not a bad seal.
- DIY replacement is realistic on a straightforward door; getting the wrong profile is the most common reason it goes wrong.
- On an older door already showing other signs of wear, resealing on its own can be a short-term fix for a longer-term problem.
What The Seal Actually Does
The rubber seal running around a uPVC door’s edge compresses when the door closes, creating an airtight, weathertight barrier between the moving door and the fixed frame. It’s a wear component by design — flexing and compressing every time the door opens and closes, sitting in direct sun and weather on the outward-facing side, and doing this thousands of times a year. It isn’t a sign of a badly made door when it eventually fails. It’s a sign the door has been used.
Signs Your Seal Needs Replacing
A healthy seal is soft and springs back when pressed. A failing one has gone hard, flattened its shape, cracked along its length, or shrunk away from the corners. The simplest check is the paper test: close the door on a strip of paper at several points around the frame. If it pulls out with no resistance, the seal isn’t compressing properly at that point. A torch held to the frame from outside in a darkened room, checked from inside, will also show light coming through any real gap.
How Long Seals Actually Last
A quality seal on a well-fitted door typically lasts 15 to 20 years before it needs attention, though south-facing doors that take more direct UV tend to go first. Once a seal has hardened and lost its compression, no amount of cleaning restores it — replacement is the only fix at that point.
When It’s Not The Seal
This is the check that most guides skip, and it’s the one that actually saves money. Before ordering a replacement seal, rule out the other common causes of a draughty door.
A door that’s visibly sitting unevenly in its frame — tight on one side, gapping on the other — has usually dropped slightly on its hinges, which is a hinge adjustment, not a seal job. A multipoint lock that isn’t pulling the door fully tight against the frame when locked will leave a draught that no seal can close, because the door simply isn’t being drawn in far enough. Draughts from around the glass rather than the frame perimeter point to a failed glazing bead seal, a different repair entirely. And a genuinely distorted frame, more common on older doors, can create gaps a new seal physically can’t bridge.
We’ve covered why correct sealing depends on more than just the rubber strip itself in why proper sealing matters more than you think, and the wider signs a door is losing heat in signs your door is letting heat out and what to do.
DIY Seal Replacement
Most uPVC door seals clip into a groove rather than being glued, which makes this a realistic DIY job on a standard door. Remove a short section of the old seal from a corner to identify its profile before ordering — seals vary in cross-section between frame manufacturers, and getting a mismatched profile is the most common reason a DIY job doesn’t sit properly. With the door open and secured, work the old seal free around the full perimeter, clean the groove thoroughly, then press the new seal into place, starting at a corner and working around, trimming the excess at the join. Replacement seal typically costs a modest amount per metre as a market range, making this one of the cheaper repairs available on a uPVC door.
DIY Versus Calling A Fitter
If the door is otherwise sound and the fault is clearly the seal, DIY is a sensible route and the cost of getting it wrong is low — worst case, a second attempt with the correct profile. Where it’s worth calling a fitter instead is when you’re not confident diagnosing the cause, when the door shows other signs of wear alongside the draught, or when the seal groove itself looks damaged rather than just the rubber. A fitter can also check the mechanism and alignment at the same time, which a straight seal swap won’t tell you anything about.
When Resealing Isn’t Worth It
This is the honest part. On a door that’s 15 to 20 years old or more, a failed seal rarely shows up on its own. It tends to arrive alongside a stiffening mechanism, slight misalignment, or condensation between panes if the door has a glazed section — all signs the door as a whole is reaching the end of its useful life, something we’ve written about in more detail in common front door problems and when to replace yours. Resealing that door will genuinely stop the draught for a while. It won’t stop the rest of it catching up, and years of UK weather don’t make that easier, as covered in how UK weather impacts door and window performance over time. If you’re weighing up a reseal against a longer-term view of the door, our uPVC doors page is a reasonable place to compare what a replacement actually involves before you commit to either.
Frequently Asked Questions
How do I know if my uPVC door seal needs replacing?
Check whether the rubber is still soft and springs back when pressed. If it’s hard, flattened, cracked, or shrunk away from the corners, it needs replacing. The paper test and a torch check from outside will confirm a specific gap.
How long do uPVC door seals last?
Typically 15 to 20 years on a well-made door, with sun-exposed doors tending to wear faster than shaded ones.
Can I replace a uPVC door seal myself?
Yes, on a standard door this is a realistic DIY job. The main risk is ordering the wrong profile, so match a sample of the old seal before buying a replacement.
How much does it cost to replace a door seal?
Replacement seal is sold by the metre and is one of the lower-cost repairs available on a uPVC door, as a rough market range, before any labour if you’re not doing it yourself.
Why is my door still draughty after replacing the seal?
The seal probably wasn’t the actual cause. Check for a dropped or misaligned door, a mechanism that isn’t pulling the door fully tight, or a failed glazing bead seal around the glass.
Is it worth resealing an old uPVC door or should I replace it?
If the door is otherwise sound, resealing is worth it. If the seal has failed alongside other signs of wear on an older door, resealing is a short-term fix and it’s worth considering whether replacement makes more sense.
What This Actually Comes Down To
A draughty door is almost always fixable, and a seal swap is genuinely one of the cheapest, most effective repairs going when the seal is actually at fault. The two-minute check that tells you whether it is, or whether you’re looking at something bigger, is worth doing before you buy anything.