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Why Is There a Draught Coming Through the Bottom of My uPVC Door?

For a closed uPVC entrance or patio door where cold air can be felt around the bottom edge or one lower corner despite the door being locked.

By Home ManualReviewed 1 September 2026Safety level S1UK guidance
Quick answer

What this usually means

A draught at the bottom of a uPVC door usually means the door is not compressing evenly against its weather seal. The door may have dropped slightly on its hinges, the bottom gasket may be flattened or damaged, the multipoint lock may not be pulling the sash tightly into the keeps, or the threshold seal may be worn or incorrectly adjusted. A draught concentrated in one corner is especially suggestive of alignment rather than a whole-door insulation problem.

Likely causes

What may be causing this

1

The door has dropped slightly on its hinges

Clues: The gap is uneven, the lower latch-side corner is worst, or the door also catches slightly when closing.

What to do: The hinges may need height or lateral adjustment so the sash sits squarely in the frame again.

2

Compression against the gasket is too low

Clues: A sheet of paper pulls out easily from the draughty area but is gripped more firmly elsewhere.

What to do: Adjust compression only using the correct hinge or locking-point method for that door, making small changes and retesting the lock.

3

The weather gasket is worn, flattened or damaged

Clues: The seal looks cracked, hard, shiny, torn or permanently compressed at the bottom.

What to do: Replace it with the correct profile rather than packing the gap with unrelated foam strips.

4

The threshold or bottom seal is worn or misadjusted

Clues: The draught runs across the bottom edge rather than one side, and the door itself appears square.

What to do: Inspect the threshold seal and adjustment system, if fitted, and replace damaged components.

Diagnose the pattern

How to check what is happening

Run a hand around the closed door edge on a windy day
The draught is concentrated at one lower corner

Door alignment or local compression is likely.

Close the door on a sheet of paper at several points
The paper slides out easily only near the bottom

Seal compression is weaker at that part of the frame.

Inspect the gasket
The rubber is flattened, torn or hard

The seal itself may no longer be able to compress properly.

Operate the multipoint lock
The handle is stiff, or the door must be pushed/pulled to lock

Alignment is already poor and aggressive compression adjustment could worsen the lock.

DIY decision

Can you fix this yourself?

Checking seals and performing a paper test are easy. Small hinge adjustments can be DIY on clearly identified hardware, but if the lock is stiff, the door has dropped significantly or the threshold is damaged, a window/door fitter should realign it.

You'll usually need:
  • Sheet of paper
  • Torch
  • Correct Allen key only if the hinge type is confirmed
  • Silicone-safe seal cleaner
Step by step

What you can safely try

  1. 1

    Locate the exact draught path

    Check the hinge side, lock side and threshold separately so you know whether the problem is one corner or the whole bottom edge.

  2. 2

    Compare seal pressure with a paper test

    Close the door on paper at several positions. Uneven resistance shows where the sash is not compressing the gasket consistently.

  3. 3

    Inspect the bottom and corner gaskets

    Look for tears, flattening, shrinkage or seals that have pulled out of their groove.

  4. 4

    Check whether the door is square and locks smoothly

    A dropped door often shows uneven gaps and extra resistance when the multipoint lock engages.

  5. 5

    Adjust alignment or replace the failed seal

    Make only small hardware adjustments and retest frequently. Replace damaged seals with the correct profile instead of over-compressing the door.

Stop conditions

Call a window fitter if…

  • The lock or handle is already stiff or difficult to operate.
  • The door does not latch or lock securely.
  • Hinges are cracked, loose from the frame or badly worn.
  • The frame is visibly distorted or loose.
  • Adjustment screws are seized or the hinge type is uncertain.
Still need help?

Get the right professional.

This problem can have more than one cause. Start with the checks above: a window fitter is the usual first route, while a locksmith may be more appropriate when the clues point that way.

Find a window fitter →
Evidence

Sources used for this guide

We prefer primary UK guidance, regulators and manufacturers for technical and safety-sensitive claims.

  1. How to Adjust UPVC Door Hinges to Stop DraughtsScrewfix
  2. How to Adjust a uPVC Door: Hinges, Drops and DraughtsSpar Windows

Last reviewed: 1 September 2026. Home Manual updates review dates only when the substance of a guide is checked or changed.

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