UPVC Windows Cold Wall

13 Dec 2022
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United Kingdom

Looking on some advice please. Windows on our house were fitted 10 years ago, just before our purchase. Since moving in i have always felt the house is cold, and we spent time replacing panel radiators, boiler, double insulated roof, Tado Smart Heating etc. The house does get nice and toasty, however as we are now trying to use less gas we can see that temps in rooms drop fast. An example of this is 20 degrees at 10PM when heating turned off, 12 degrees by 4AM.

I find that i pickup on cold draughts very easily, and struggle sitting at my desk at home which is 3 feet from the window due to a draught. The seals are fine and even tried the candle test. I have borrowed a thermal camera, and windows are showing 15-16 degrees inside, whilst outside shows -1 to 1 degree which i dont think is bad. What i have noticed is the bottom corners of window sill and wall is very cold. This shows a temp of say 8-9 degrees, whilst the wall facing into room shows 16-18 degrees. We also get a lot of condensation on the windows and mould growing in the corners where is it coldest. We try to vent rooms with windows open a hour each day and Tado reports humidity is not bad.

After doing some research I'm convinced there is no cavity stop or insulation installed around windows. Cavity walls does have insulation, we had this checked by a company (house built 1988). Another thing i remember a few years ago was that the wall outside by window sills and doors appears to have been cut for the sill to fit. The brick on some windows was loose, so i removed them blasted in a bit of expanding foam and re-fitted the brick and used some window sealant. This was not done to all windows, maybe 1 or 2.

I have been told to try popping a hole into the wall at the corner where they are cold and see if i hit a plastic cavity stop or some foam. If i dont then use a foam gun and blast in some foam. They said try this every 3 inches up wall and then just fill over holes once the foam has dried.

What's people thoughts on this?
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Yes, filling edges with foam should help as it looks like there are cold spots there. Its very common to have voids behind those areas that lets the cold in.

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