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UPVC windows

Help! I bought a boat with square edge domestic upvc windows already installed. Whilst they look ok and are good for heat retention and condensation - they leak. Any ideas please?

Asked by: J Morton  | 12.59pm, Tuesday 26 March


WW says:

PVC house windows are not often seen on boats because they are designed to be mounted vertically, not at the slight slope of boat cabins.
The first thing to establish is whether the leak comes from the window itself, or from the mounting to the cabin side. If it is from the window sealing into the PVC frame, it will be difficult to solve. It is however most likely to be leaking where the frame seals to the metal. If the window is not sufficiently well fixed, with a flexible sealant, the different expansion rates of plastic and metal will break the seal and water will get through.
The only good way to permanently solve the problem is to take the window out and re-fix it with new sealant.

Rupert Smedley  | 4.11PM, Tuesday 26 March


Readers say:

Thank you Rupert, I'll give that a try

J Morton  | 9.30AM, Wednesday 27 March

Do NOT use any mastic if leak is between glass and upvc frame as you will never get the glass out ever again. Silicon may be ok but ask a window fitter for advice.

Gary  | 8.20PM, Monday 13 May

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