Damp plaster around upvc windows - update:no improvement

[Landycat]

Hi,My double glazing was done years ago,to replace metal 'crittal' type windows,but it's always been cold,draughty and never really kept out the noise from outside.

I decided to have a look to see what was wrong,and found that the windows had been fitted to the plaster,rather than the brick opening,and that they'd glued upvc strips around them to fill the gaps around the edges - gaps of up to 15mm,but at least 10mm.

There was no foam or insulation between the frame and the opening,and where the filler strips had been fitted they'd been cut off level with the bottom of the frame - this leaves a void that you can see into from outside,which probably isn't good (unless you're a spider looking for a home).

I removed all the old sealant outside and renewed it,then hacked off some plaster inside to get access to the void and filled it with spray foam,then plastered over it - job done,I thought...nice and quiet and no draughts.

But...

I now have a permanent damp patch at the bottom corners of both the windows I worked on,and one window has a small damp patch about half way up when it rains.

What did I do wrong,and what do I do now?

 

[Gazman16]

Can you post some pics inside and out?

 

[Landycat]

Some images as requested.

window 2

• Landycat
• 18 Jan 2014
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window 1

• Landycat
• 18 Jan 2014
• 1

window 1

• Landycat
• 18 Jan 2014
• 1

window 2

• Landycat
• 18 Jan 2014
• 1

Edge strip with gap underneath

• Landycat
• 18 Jan 2014
• 1

gap between frame and wall

• Landycat
• 18 Jan 2014
• 1

 

[Gazman16]

Does it smell like cat pee?

If it was just the bottom corners I would say you just need to get a load of silicone in behind the bottom of the trims to get the corners well sealed.

Could be also worth running a bead of white silicone all around where the frame meets the trim, At very least seal the joins at the top where the side trims meets the top one.

 

[Landycat]

Does it smell like cat pee?

If it was just the bottom corners I would say you just need to get a load of silicone in behind the bottom of the trims to get the corners well sealed.

Could be also worth running a bead of white silicone all around where the frame meets the trim, At very least seal the joins at the top where the side trims meets the top one.

That's grumpy Jasper on the window sill,and I did give the areas in question the 'sniff' test before posting.

Should I seal all along the gap between the frame and the sill with silicone,or just fill the corners?
I guess I missed the join at the top of the trims - well spotted.

 

[Gazman16]

Just the corners, There will be concealed drainage between the window and the cill

 

[Landycat]

Just the corners, There will be concealed drainage between the window and the cill

I'll get that done and see what happens,then report back with the results.

 

[Landycat]

Well it seemed to dry out a bit,and the damp patches shrank,but after a couple of days of rain the damp's worse than ever.

I'm wondering if the foam's soaking up the moisture from the outer brickwork (cavity wall) which is then making the plaster damp?

What should I do now?

 

[Gazman16]

Bummer.

Fixing foam is not waterproof as such but it dosent absorb water so it shouldn't be causing the problem.

Now its a case of trial and error (short of taking out the whole window and refitting).
1st thing I would do is take off the side trims, Dig out an inch of foam at the bottoms and see what you can see (take some pics). Look for anything that is bridging the inside to outside like the cement at the corners.

If there is nothing obvious then completely fill the 1 inch gap with silicone (Try to get it in the gap between the window and cill too), refit and reseal the trims.

 

[pinenot]

Is the wall in question solid brick or cavity built, you probably can't answer the next one unless you were there when any (particularly this one) of the windows were taken out! If they are cavity were the slap reveals closed or open i.e. were the bricks returned at the window slaps/apertures to close and meet the inner cavity wall?
I ask because I see a fillet of what looks like cement/mortar has been applied to the cill lugs each side of the window. These could easily conduct water, should there be any cracks, inward through any mortar gap/crack (these can be very hard to spot via the naked eye) and as you seem to be having wind driven dampness, when this would become most apparent. Also I would always recommend polysulphide for sealing the frames to walls, as it never fully sets, skins/cures on the surface only, and always remains stretchy (no cracks)...pinenot

 

[Landycat]

Is the wall in question solid brick or cavity built, you probably can't answer the next one unless you were there when any (particularly this one) of the windows were taken out! If they are cavity were the slap reveals closed or open i.e. were the bricks returned at the window slaps/apertures to close and meet the inner cavity wall?
I ask because I see a fillet of what looks like cement/mortar has been applied to the cill lugs each side of the window. These could easily conduct water, should there be any cracks, inward through any mortar gap/crack (these can be very hard to spot via the naked eye) and as you seem to be having wind driven dampness, when this would become most apparent. Also I would always recommend polysulphide for sealing the frames to walls, as it never fully sets, skins/cures on the surface only, and always remains stretchy (no cracks)...pinenot

Hi,the walls are definitely cavity,but there was a gap of maybe an inch when they tore out the old metal window frames.

There were concrete sills,but some were badly cracked so we were talked into having them replaced with upvc sills when they did the window frames.
There doesn't appear to be much thickness of mortar,mostly foam with a thin covering of mortar,but I applied sealant around the cement too where it seemed suspect.

Maybe I should dig out the areas of damp plaster and maybe isolate the area from outside with a layer of silicone,then plaster it up again?