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[Jemster]

We bought a 1920s solid brick build house a couple of years back and have been working through the issues bit by bit.

One problem that is coming up time and time again is regarding the windows. They are uPVC frames, probably fitted 30+ years ago and put quite simply. They leak. Not every one, but a good few of them that we know of, and maybe more we don’t!

As far as I can determine, the water seeps under the frame. Or along a vertical edge and runs down to the corner. I’ve slipped DPC under one of them to see if maybe there are cracks in the frame, thinking I’d see water on top of the DPC sheet, but no. The damp is below the sheet, not above.

The drain holes are clear. The seals SEEM reasonable, but I’m thinking as the drains are clear, would this make any difference if they were letting in a little water as it would surely drain out. The window units are good without any internal misting.

To be honest, it’s a real headache. The house has some damp issues and I reckon 95% of them are due to this same problem at various windows.

How do I fix them? What way SHOULD the windows be fitted that I could possibly check and say these are leaking because they need refitted with ???

If I bought new frames (and with 22 of them, that would be no small bill) wouldn’t they suffer the same problem if fitted in the same way?

I’m thinking about fitting external pvc strips around the frames in an effort to keep the water back perhaps?

Any thoughts welcome...

[stoneyboy]

Hi jemster
If the frames have a projecting sill check that the drain holes in the window frame itself are clear - they should be visible under the opening casements.
After 30 years it is possible that the internal drain channels are blocked with debris and water is draining out the ends of the frame. Forming extra drain holes will be easier than trying to remove frame components for cleaning.
Regards S

[Jemster]

Hi stoneyboy,
Thanks for the reply. They don’t have sills. The window frame is installed sitting directly on the original cement (concrete?) sills. The drain holes are clear, there is no casement on at least one with the problems.

I have tucked strips of DPC under the frame, so between the frame and the cement... in an effort to work out if it could be some form of leakage within the frame (then dripping down onto the sill) but the top side of the DPC is dry as a bone.

To give you an idea, here’s a view from inside showing a corner and some of the damp..

From the outside, this is the typical arrangement (different window, same idea)

Should the frames actually be sitting on something? If silicone is the only thing preventing water ingress, this seems a bit impractical long-term?

I’m kinda at a loss, reading around it seems it’s not unusual, but being a solid brick wall with no cavity to isolate the water from the internal wall, I don’t know what a good solution is. Obviously if an interior sill is fitted then this could (and has) go on for years without people spotting it and I’m not sure what the damage is to the brickwork beneath it?

[stoneyboy]

Hi jemster
It is inevitable that water will get past the seals and this will get worse as the rubber ages. The problem is to determine whether adequate provision in the form of drain holes (at the appropriate height and position) are present and whether debris has collected around the drain holes, so they may appear clear from the outside.
The only way to check this is to remove the DGU’s and see what is going on.
Regards S

[Jemster]

So an interesting follow up to this problem that may be of use to others, plus a question of course...

It turns out that the leaks are coming on the joint between the frame and the snap-on extender bar at the bottom of the window. Water is getting into the minute gap, running along and emerging at the window edges.

I found this because we have a downstairs bathroom window with an extender on the bottom and another on the side. I re-sealed outside and re-cemented the lower gap. I then sprayed water on the window and observed that the dampness started at the point where the vertical snap-on joint touched the sill. I then bought some Gorilla waterproof tape and taped the external joint between extender and frame. Repeated the experiment and now there’s no sign of any dampness at all!

So these extenders are b*ll**ks and I need a permanent fix. I’m thinking a plastic weld glue, something to try and bond the two pieces together. Obviously there’s no way to separate the 2 components to get glue in there, so any suggestions as to what might work well?