Poor Mike Pocock and his discolouring uPVC windows (AJ 10.10.02). English Heritage's Framing Opinions Campaign of the early 1990s did warn specifiers and the public that this would happen.
Plastic window installers' guarantees have been getting shorter and now ICI Dulux (the world's number-two paint company) has started selling PVC paint for repainting plastic 'maintenance-free' windows.
The European and British standards for the weathering resistance of uPVC (predicting 25 years without change) has small print along the lines of 'accelerated weathering tests are not a very accurate facsimile for real-time weathering and circumstances may vary from place to place'.
I have seen windows yellowing in five, 10 and 15 years of exposure - those at the seaside and in rural areas under big open skies suffering the quickest deterioration. The yellowing and chalking of plastics through UV light attack will not go away - there are no miracle cures.
Want the other concerns?
Rumours abound in the window industry about 40 per cent of all British Standard sealed doubleglazed units failing within five years - hence the growth of 'window doctor' company adverts in the local free papers.
Gaskets and mastics used in the installation of the windows also deteriorate in UV light.
How sustainable and low maintenance are these products then?
John Fidler, director of conservation, English Heritage