Custom window seals
Window seal with locking strip and filler strip
Locking-strip profiles clamp the pane tightly and watertight with a pressed-in (filler) strip. We make custom window seals with locking strip, matched to your glass and frame thickness.
A locking strip (also: filler strip, closing strip or insert) is a separate strip that you press into the groove of the window seal after fitting. This puts the profile under tension: the walls are pushed apart and clamp the pane and rebate tightly and watertight. Without the strip, the rubber sits loose. A decorative strip is a visible, ornamental version (often chrome or coloured), widely used on classics.
What does the locking strip do?
A window seal (also glazing rubber, H-profile or keder profile) seals a pane, clamps it in place and protects the edge of the glass. A locking-strip profile has a groove running along it into which you press the strip. Drawing in the strip puts the rubber under tension, providing the clamping force and the water- and draught-tight seal.
The strip is usually made of plastic (PVC) and comes in various thicknesses. A thicker strip gives more clamping force.
With or without a locking strip?
Choose one with a locking strip when you want a removable, tightly clamped and watertight seal for a loose pane in a rebate: vehicle and cab windows, boat and ship windows, machine panes and vintage cars.
Without a strip uses a self-clamping profile, a clamping profile (D or saddle profile) or bonded glazing. Common on caravan and motorhome windows, light sheet materials and modern bonded panes.
Filler strip, closing strip and decorative strip
- Filler strip / closing strip: the functional strip that fills the groove and tensions the profile. Usually discreet, in the colour of the rubber.
- Decorative strip / trim: a strip that is also ornamental, visible on the outside in chrome, aluminium or a colour. Widely used on vintage cars.
Please note: a locking-strip tool is suitable for plastic (decorative) strips; metal trims sometimes require other tools or techniques. See also locking-strip tools and fitting materials.
Custom locking-strip profile
We make locking-strip profiles and matching strips to measure, tailored to your glass thickness and clamping range, in EPDM, TPE or silicone. Also for vehicles, boats, vintage cars and machinery. Request a quote or view our window seals.
Specifications at a glance
| Profile type | Locking-strip profile (window seal with strip groove) |
| Locking strip | Plastic (PVC); decorative strip in chrome or colour |
| Rubber material | EPDM, TPE or silicone |
| Matching | To the glass thickness and frame thickness (clamping range) |
| Supply | Profile and strip made to measure from a sample or profile code |
Frequently asked questions
What is a locking strip on a window seal?
A separate strip that you press into the groove of the window seal. It puts the profile under tension, clamping the pane and rebate watertight.
What is the difference between a locking strip and a filler strip?
Both terms usually refer to the same closing strip. ‘Filler strip’ emphasises that the strip fills the groove and puts the rubber under tension.
What is a decorative strip?
A locking strip that is also decorative, for example in chrome or a colour, and stays visible on the outside. Often used on classics.
Do I always need a locking strip?
No, only with locking-strip profiles. Clamping profiles, self-clamping profiles and bonded glazing work without a strip.
Which locking strip do I need?
A strip that fits the groove of your profile; the thickness determines the clamping force. Send a sample or profile code and we will determine the right size.
Can I reuse an old locking strip?
Usually not recommended: old plastic strips become hard and brittle and clamp less well. New rubber with a new strip is better.
Why does my window leak despite the locking strip?
Often the rubber has hardened or become porous, or the strip has not been drawn in fully and evenly. Check the rubber for hardening and the strip for correct fitting.
More about window seals
See also our other pages about custom window seals:
Custom window seal with locking strip
Profile and strip matched to your glass and frame thickness. Send us a sample or profile code for a suitable proposal.
