EPDM gaskets and wool pile — replacing weatherseals

Weatherseals are the cheapest part of a window and the first to fail. Replacing them is routine maintenance, not a rebuild.

EPDM vs PVC gasket

Many windows ship with a soft PVC glazing and weather gasket. It hardens, shrinks and cracks within a few years in direct sun. EPDM rubber stays flexible for far longer, resists UV and ozone, and keeps its compression set. When you re-gasket, switch to EPDM on the weather-facing side — the cost difference is small.

Measuring for a gasket

• Identify the groove width and the glass or sash gap the gasket bridges.
• Note the profile: wedge (glazing), bubble / E-section (compression weatherseal), fin (wiper). Bring a 100 mm offcut of the old gasket — matching the section by eye from a chart is unreliable.
• Buy a little extra; corners and mitres waste length.

Wool pile (brush) seal

Sliding windows and doors seal on wool pile — a woven brush strip in a T-slot, sometimes with a central fin (fin pile) for better air sealing. It packs down and wears. To replace:

• Measure the backing width (the T or the slot) and the pile height above the backing.
• Pull the old strip out of the slot and feed the new roll in; trim at the ends.
• Fin pile for weather-facing sliders; plain pile for interior and light doors.

While you are there

Check the drainage slots in the bottom rail are clear — a blocked weep hole makes a window “leak” no matter how good the seal.

We stock EPDM gasket sections, bubble weatherseal, and plain and fin wool pile by the roll. Bring the offcuts.