Window frames seem to be rotting... :(

6 Dec 2011
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United Kingdom

I can't find the solution to my problem anywhere, so I thought maybe someone here would be able to help. Me and my husband are comblete newbies at DIY. We bought a loft flat 5 years ago with skyline (?) double glased windows, with what seems to be hardwood frames. Nobody told us that these windows need any maintenance, and maybe they don't, but I noticed now that most of them have darkened varnish alond the bottom frame and two window frames have cracked moist wood - almost like they are rotting. We do have condensation in the flat, but not too much and we use dehumidifier and bathroom fan. I also open windows regularly for ventilation, but during winter, there's always moisture just along the lower window frame and this is where it's all dark and cracking.

The question is how bad is it? Do we need to replace windows now? Do we have to sandstone it and apply new varnish/paint? Is it normal and we should just leave it alone? It doesn't look good...Any advise on possible fixes would be appreciated.

Thank you,
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All woodern window frames need maintainace (as do, to a certain extent, uPVC) which includes rubbing down and repainting inside and, more critcally, outside.

The frequency this is required depends on conditions and the quality of the material used, although varnish typically doesnt last as long as paint. It is also far less tollerant in terms of the ability to patch/fill soft timber. Although of cause you can always paint over varnish if you are happy to accept a painted finish.

I have also had success with 'wood hardener' which is thin a and clear, soaking into the soft wood and going hard. You obviously then have to dry and keep dry the wood, but while a bit of a bodge, its not a bad one and lasts fairly well extending the life of the window.

In this weather you are not going to get it dry enough to do much about it, but I would get someone round to quote for doing the work come spring.

I think Daniel is absolutely correct - there's little you can do at this time of year. Once the dry weather returns and the timber has had time to dry out yyou'll be better able to asses the situation.

We acquired a house a few years back where the Velux opening lights were just starting to go the same way. they've responded well to being sanded back, treated with Bonda Voss wood hardener then sanded back and revarnished. Where we had black staining I took it out with a solution made from oxallic acid crystals and then neutralised the acid with a mild alkali wash.

Where the rot is worse, i.e. the timber is actually rotted, it becomes necessary to dig out the rotten timber with a combination of old chisels and steel wire brushes before applying wood hardener. The resulting holes are then best filled with a 2-pack epoxy wood filler. This article will give you some idea of what can be done. I've used that sort of product on pub doors (very large ones which always seem to rot just behinfd the weather bars), etc quite a few times, but those structures are paint finished and if your windows need that sort of attention you'll find that clear lacquering won't look all that wonderful. A readily alternative is 2-pack flexible car body filler, although that does need to be built-uo in thin layers
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condensation in the loft? very common. Water vapor is lighter than air so it rises until something stops it. Improved ventilation will help.

It will be far worse if anyone drapes wet washing around the house or over radiators.

Maintenance-free wooden windows have not yet been invented.

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