Service gaskets for windows - EPDM rubber
Gaskets for servicing and resealing older windows. EPDM rubber - resistant to UV, ozone and frost, still springy where the old gasket has long given up.
After a dozen or so years the gasket in a window hardens, shrinks and stops closing the gap. The window starts to draw, the glass mists up and heating bills rise in winter. Replacing just the gasket costs a fraction of a new window and in most cases is entirely enough to restore the seal.
We supply service gaskets for PVC, aluminium and timber joinery - for windows and doors. We match them to the specific profile, from a piece of the old gasket or a photo of the groove cross-section.
Rebate gasket (with sealing lip)
The main service gasket - it runs around the sash and closes the window
It is held in the profile by an anchor foot, commonly called a fir-tree foot. The foot is pressed into the groove, so the gasket needs neither adhesive along its whole length nor the sash to be removed.
What we look at when choosing
| Feature | What it determines |
|---|---|
| Foot width | Must match the groove in the profile - it decides whether the gasket stays put |
| Lip height (G) | Sets the pressure and whether the window closes without resistance |
| Hardness | About 60-70 Sh A - soft enough to seal, springy enough to recover its shape |
| Colour | Black, grey, beige, brown, golden oak |
Glazing gasket (with hollow bulb)
It works between the glass and the glazing bead
The bulb has to match the clearance between glass and profile. Too soft and it will not hold pressure; too hard and the glazing bead will not click into place.
Mullion gasket (hollow-chamber)
Hollow-chamber profile with a sealing wedge - for mullions and structural couplers
Locating wings on either side of the base stop the gasket twisting in the groove as it is pressed in.
Material
Why EPDM rubber rather than ordinary rubber
EPDM stands for ethylene propylene diene monomer. It is a synthetic rubber that has replaced older rubber compounds and soft PVC in window gaskets.
The difference only shows after years. EPDM does not crumble under UV or ozone, does not harden in frost and does not stretch permanently under the pressure of the sash. It works roughly between -40 °C and +90 °C, so neither winter frost nor a sun-heated frame changes its properties. Typical hardness for window gaskets is around 60-70 Sh A.
An old gasket that does not spring back under finger pressure, is flattened along its whole length or cracks when bent is due for replacement. That is the most common cause of a leaky window - more common than worn hardware.
What you can replace yourself
The rebate gasket - without removing the sash or the glass
Pull the old gasket out of the groove by hand, starting at a corner. Wipe the groove dry to clear dust and remnants of old rubber. Press the new gasket in by its foot, again from the top corner, and work your way round. Never stretch the gasket - lay it in loosely, because a stretched gasket will shrink over time and expose the corners. Cut it with a small allowance only once the whole perimeter is laid, and join the ends butt to butt with a drop of rubber adhesive.
What is better left alone: the glazing gasket, because it means taking off the glazing bead and it is easy to loosen the glazing in the process, and gaskets in aluminium windows and hollow-chamber constructions. For that sort of work it is worth calling a fitter.
We describe it step by step in our guides.
More from our range
Replacement gaskets for windows - for refurbishing older joinery
Replacement gaskets are seals meant to be fitted into windows and doors already in use - as opposed to the gaskets fitted at the works during manufacture. After a decade or more a gasket hardens, shrinks and stops closing the gap, so the window starts to let draughts through, holds heat less well and dampens less noise. At the TECHNOLOG wholesale we carry gaskets in EPDM rubber, resistant to ageing, frost and UV, matched to the particular profile system of the windows and doors - PVC, aluminium and timber.
How to choose a gasket for servicing PVC windows
A gasket is chosen by the shape of the groove and its section, not by the name of the window. Three things matter: the width of the anchoring foot, the height of the sealing lip and the hardness of the material, which for window gaskets is usually around 60-70 Sh A. The surest way is to pull a 10-15 cm length of the old gasket out of the groove and match it to the pattern; a photo of the section with a ruler alongside will also do. As a wholesaler trading since 1994 we help pick the right profile, and in the Stargard area we also carry out the replacement ourselves. We ship throughout Poland.
Replacing gaskets in old windows - yourself or through a fitter?
The compression gasket, the one running round the sash, can be replaced yourself. Neither the sash nor the glass has to come out: the old gasket is pulled from the groove, the groove wiped dry, and the new one pressed in by its foot starting at the top corner. The gasket must not be stretched - laid too taut it shrinks in time and leaves the corners bare. The ends are cut to butt and joined with a drop of rubber adhesive. It is different with the glazing gasket, which requires the glazing bead to be removed, and with gaskets in aluminium windows and in hollow-chamber constructions - for those a fitter is the better option. A sound gasket saves real energy: an airtight window holds heat better in winter, cuts draughts and dampens noise more effectively.
Collection at the weekend too
We hand goods over during the week, but the collection time is agreed individually - including on a Saturday and, if need be, a Sunday. Just arrange it with us by phone beforehand. Customers living and working in Germany often use this, collecting their material when they come back to Poland - we speak Polish, so there is no need to translate profile names or describe a problem in a foreign language. Orders for weekend collection should be placed by Friday 12:00 at the latest so we have time to make the goods up.
Frequently asked questions
They are gaskets meant to be fitted into windows and doors already in use, that is for servicing and sealing older joinery, rather than for factory installation.
EPDM is ethylene propylene diene monomer rubber. Unlike ordinary rubber and soft PVC it does not crumble under UV and ozone, does not harden in frost and works roughly between -40 and +90 degrees Celsius.
When it does not spring back after being pressed with a finger, is flattened along its whole length or splits when bent. In the window this shows as draughts, condensation on the glass and more noise from outside.
The compression gasket around the sash, yes - all you need is scissors and a flat screwdriver, with no need to remove the sash. The glazing gasket is better left alone, because it requires the glazing bead to come off and the glazing is easily loosened in the process.
The compression gasket works between sash and frame and closes the window with its sealing lip. The glazing gasket works between glass and glazing bead and presses the pane with a bulb.
Just pull a 10-15 cm length of the old gasket out of the groove, or send a photo of its section with a ruler or a coin alongside for scale. On that basis we will pick the right profile.
Yes, the collection time is agreed individually - including on a Saturday and, if need be, a Sunday. Please place the order by Friday 12:00 at the latest so we have time to prepare the material.
Have questions about a product? Get in touch with us!
Contact us by sending a message or calling. We are fully available by phone Monday to Friday from 8:00 to 18:00.