uPVC and aluminium frames share similar arrangements:

  • Double glazing panes should sit on blocks within the uPVC frames ? not be in direct contact with. The two panes must be supported equally to prevent ?slippage?.
  • The framework should have adequate drainage, either through holes hidden from view, or visible ?face? drains.
  • There is good ventilation around the double glazing glass as air can circulate through the drainage holes.
  • The double glazing is fitted with clip-on beads. A gasket, or double sided tape is on the other side prevents most water ingress.

When a double glazed sealed unit fails

A double glazing seal is said to have ?blown? when the perimeter has lost its integrity and moisture is getting inside and between the two panes of glass.

The levels of moisture in the air changes throughout the year, but even at the height of the summer, our breath still contains moisture.

As atmospheric pressure changes, the force will be put on the double glazing unit and moisture will be drawn in through the breach.

Listed below are some of the more common causes for premature failure in double glazed windows.

Glazing not sealed correctly during manufacture

It would only take a short period of time for a double glazing window to fail if it?s not sealed properly. It could be in as little as one year.

Windows not seated correctly on glazing blocks

The effect this has on premature failure varies from case to case. If draining was blocked as a result, it would be the worst case scenario. Even a small amount of water getting in would half the unit?s life expectancy.

Exterior seals not fitting correctly and letting water in

This has a very similar effect to the last topic. However, if some of the water breaching the perimeter contains washing up liquid, or similar, it will attack the seal. Anything stuck together will come apart quicker if immersed in water. This process will be even quicker if the water contains a solvent.

Flexing of the framework

Any pressure exacted on the framework will not do it any good. Conservatory double glazing is most at risk and they should always be fully reinforced if uPVC. This helps to protect the windows against flexing caused by wind loads.

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