Why Can I Feel a Draught Around the Opening Part of My uPVC Window?
For a draught felt around the edges of an opening uPVC sash even though the glass itself is intact and the window closes.
What this usually means
A draught around an opening sash usually points to compression, alignment or weather-seal performance rather than failed glass. The GGF notes that damaged hinges, catches and stays can distort frames and make draught and weather seals ineffective. Check for a folded, missing or hardened gasket and compare the sash gap around all four sides. If the sash is not being pulled evenly onto the seal, alignment or locking hardware may need adjustment before any gasket is replaced.
What may be causing this
The weather gasket is damaged, hardened or displaced
Clues: A visible section is split, flattened or pulled out of its groove.
What to do: Clean and reseat only if the system permits, or have the correct gasket replaced.
The sash is out of alignment
Clues: The gap is tighter on one side and wider on another.
What to do: Have hinges or sash position adjusted.
The locking points are not providing even compression
Clues: The window closes but one edge does not pull firmly against the seal.
What to do: Have keeps and locking hardware checked rather than over-tightening at random.
How to check what is happening
The seal itself is contributing.
Alignment may be reducing seal compression.
Local alignment or hardware is more likely than whole-window glazing performance.
Can you fix this yourself?
Cleaning and visually inspecting a gasket is reasonable. Persistent draught from an uneven sash should be adjusted correctly rather than packed with generic adhesive foam that can interfere with locking.
- Soft cloth
- Torch
What you can safely try
- 1
Inspect and clean the gasket
Look for splits, folds, missing sections or debris preventing contact.
- 2
Compare the sash gaps
Uneven spacing suggests the sash is not sitting squarely.
- 3
Arrange alignment if compression is uneven
Correct hardware adjustment should restore even contact with the seal.
Call a glazier if…
- The window cannot lock securely.
- The hinge or frame is visibly damaged.
- DIY packing or adjustment would interfere with the locking points.
Get the right glazier.
We already know this problem maps primarily to a glazier. Choose the closest type of work, add your postcode and continue in the form.
Sources used for this guide
We prefer primary UK guidance, regulators and manufacturers for technical and safety-sensitive claims.
- GGF Glazing ManualGlass and Glazing Federation
- When to repair or replace your windowsGlass and Glazing Federation
Last reviewed: 4 September 2026. Home Manual updates review dates only when the substance of a guide is checked or changed.