Damp penetration through wall rotting windows

[Darren9571]

Hello

I have a problem with rainwater penetration through a brick wall and the water is pooling and rotting the windows from the bottom up. I am not sure what to do??

The house is Edwardian and the wall is a SW facing gable end, 2 bricks think, no cavity. It was repointed 4 years ago and painted with Thompson waterseal, but that hasn't helped. I can't see any cracks or gaps in the mortar. It has an injected DPC. The roof is fine, there is no guttering and no plumbing, so I am sure it is rainwater penetration. The seals around the windows are good and I have maintained the paint each year. So I really don't know how the water is getting in. I have attached some photos.

The windows have only been in for about 8 years and the bottoms are pretty much rotted out. I live in a conservation area so I can't have plastic windows or render the wall.

Should I try painting the walls with Storm Dry, or do I risk making the problem worse? Am I missing a cause of the water ingress?

Thanks in advance for any suggestions.
Darren

 

[stuart45]

Looks a poor design for a sill. The brickwork should slope away from the window and extend past the line of the facework and also into the brick jambs.
Or the tiled cill could be moved up higher and do away with the Brick on edge.
Was it pointed in lime or cement?

 

[Notch7]

Do you mean the windows were fitted new 8 years ago?

In which case the problem lies with the detailing of the windows and the way they were fitted.

There isnt a damp issue with the wall. If you think about it, however dry the wall is, rainwater and condensation will get on the brick cills all the time.

Were the windows factory painted?

When being fitted, they shouldve been sat on dpc and had a dpc up the sides.

When I do windows which have a canted brick cill, I generally fitted a very small cill, say just 15mm projection, but when fitted, sits below the bottom of the window.

The window is then a bit shorter in height, packed up of the bricks and then the cill fitted to cover the gap.

It is important that new windows are fully painted on all of the external faces, with thd full paint system. This always happens if factory painted.

The detailing of the window doesnt help.

For example, the fixed sashes look like they were fitted tight. Thats a water trap. Its better to machine fixed sashes with a 3 to 4mm gap all round and drip groove all edges. It allows water in, but also to run out and air flow will dry. Capillary action will encourage water into tight gaps.

All external edges should have a 2.5mm radius, which allows a full paint film thickness around the edge. Also its good practice to have a V at tge frame and sash joints, so that timber expansion and contraction of the rails cant fracture the paint across the joint.

Were the windows made in softwood and by a local joiner?

 

[stuart45]

That wall looks really exposed to the weather. Does it take a lot of driving rain?

 

[Darren9571]

Thanks for your quick responses. To respond to your queries -

The wall takes lot of weather, it is SW facing so gets the wind and rain.
I think it was repointed with cement with PVA in, does that sound right? I asked the builder at the time if it should be a lime mortar but he said no.

The windows were fitted just before we bought the house and we have no paperwork for them (you can hear the alarm bells ringing). Basically the previous owner had the house refurbished then moved out. They are softwood, I don't think there is a dpc around them. I don't know if they were factory painted but in other places the look like they have grey paint, like a primer all round.

Sounds like I might need to consider new windows then?

 

[stuart45]

I think it was repointed with cement with PVA in, does that sound right?

Not to me, if the original was built in lime mortar.
My windows are quite rotten as well, but I've never replaced them. Just repaired them with wood hardener, filler etc.
However if I had to pay someone to do it, would probably be cheaper to renew.
The only thing to bear in mind with new ones, you need to think about the cause of the problem and solve the detailing first.
Is most of the rot at the base of the windows and what is the top one like?

 

[Darren9571]

I plan to spend today repairing them with filler, but I wanted to try and ensure I treated the cause if I could as I thought it was brick related and therefore risked water penetration into the house. But if it is related to the windows I will just keep them going for now.

 

[Notch7]

I plan to spend today repairing them with filler, but I wanted to try and ensure I treated the cause if I could as I thought it was brick related and therefore risked water penetration into the house. But if it is related to the windows I will just keep them going for now.

If you had a damp problem on the brickwork, as its a solid wall, you would have damp internally on the plaster.

 

[Darren9571]

The internal wall have insulated plasterboard on them so it would run down the back without showing on the internal plaster. This is one of my concerns - one day the floor joists will just rot through.

 

[stuart45]

I would use some wood hardener as well, it can really harden up the timber. I would say that you need to sort out the cill detail.
Was there a sand/cement fillet on top of the bricks under the window?
What happens is that as it shrinks a gap between it and the timber appears and water will run in and not escape.

 

[Darren9571]

No cement fillet, there is just a small gap (couple of mm) between the cill bricks and the bottom edge of the window.

 

[stuart45]

Problem with the brick being level is that the water does not run away from the window like it should.
Look at any cill, it is sloped for a run off.

 

[Darren9571]

Could a local joiner fit a cill now or would the windows need to come out - I think I am getting beyond my DIY abilities here and I don't know enough about how windows are fitted.

The windows do have sealant along the bottom edge, which I thought would stop the water getting in, but is is somehow getting in, pooling behind that and then being soaked up into the wood. I don't know how it is getting in to start with as the windows are sealed all the way around.

 

[stuart45]

Talk to a local chippie about putting a timber cill on for you, someone on site can always make a better judgement of the issues.

 

[Darren9571]

Thanks for your help.