Your Seal Replacement Guide for Double Glazing

If a window or glazed door begins to show signs of condensation in between the glass panes and there’s mould, or increased leaking, draughts or rattling, seal failure may have occurred and they’ll need to be replaced. A seal, or gasket, fills the gap between the glass panes and the frame under compression, in order to prevent draught and leakage. Replacement seals and gaskets, may be needed long before new window or door frames are needed, due to a number of factors that can impact upon the seal material and lead to deterioration:

· Shrinking can take place in the colder months which can warp the seal and cause it to lose flexibility.

· Heat pumping occurs when pressure builds between two glass panes in hot conditions. As with colder weather, this will lead to the contraction and expansion of the seal material.

· Direct sunlight can speed the deterioration of the sealing material. Seal failure in this way more commonly happens in windows facing the south or west, because they will be exposed to the sun for longer periods of time.

· Some strong chemical cleaning products could deteriorate the seal.

· As the double-glazing unit ages, general wear and tear may affect the sealing material.

· A faulty seal or improper installation can lead to seal failure.

Factors such as these can reduce the flexibility of the seal or gasket or leave it to become brittle. If they aren’t replaced, the moisture that that entered between the seal and the pane can cause the glass to break.

Replacing a glazing seal

Replacing a damaged or faulty glazing seal is a relatively simple task, however the most difficult aspect is matching the replacement seal to the existing one. The correct seal needs to be fitted in order to provide the optimal performance and security, so that the replacement seal will last as long as possible. There are hundreds of seal designs available, so it’s always recommended that you supply your seal provider with a sample so that they can find you an exact or suitable match.

Here’s a guide to replacing the most common types of seals:

Bubble, Flipper and ‘Bubble-Flips’

Bubble and flipper seals, and the combination of the pair, ‘bubble-flips’, are generally used to seal round doors and opening windows and are usually easy to replace. It’s a matter of pulling out the old seal from the gasket groove and inserting the new one, taking care not to stretch the sealing material and making sure it’s properly fitted around the corners.

Wedge Gaskets

Wedge gaskets are also simple to replace, by levering out at the cut ends from the frame and removing the seal by hand. You’ll need to remove and insert the new seals one at a time to maintain the tension on the other side of the glass unit. Cut the new seal lengths with an oversize of around 5% to allow for shrinkage of the gasket over time.

‘E’-gaskets

These seals are clipped into the frame and are more challenging to replace, and beading will need to be removed. To replace the beads, you’ll need to work backwards by first inserting the smallest beads and then the two longest.

Extrudaseal specialise in supplying replacement gaskets and seals in and gaskets and have over 600 designs suitable for aluminium, timber and uPVC glazing frames and bi-folding doors. For more information about replacing your glazing seals or to speak to our experienced team about finding you a matching or alternative seal, please contact us on 0121 356 8733 or email sales@extrudaseal.com.