Water ingress problems around French windows.

[David Chapman]

Greetings,

My son and his wife have been renovating a 1930s detached house which they recently purchased, and they have had an early double-glazed sliding patio door replaced by a modern double-glazed pair of French doors (installed by Sutton Windows). When this was done the window installers noticed that the old door had been inset further than it should have been, and that some bricks on either side had been hacked away in order to accommodate it.

The new doors (see the picture at

were manufactured to the correct size for the aperture but, in order to fit them properly (i.e.flush with the back of the house) and fill the space where the bricks had been damaged, the installers used expanding foam to effect a seal. (BTW, in the picture, the horizontal scar above the first row of painted bricks is where an external lighting cable originally ran. That cable has been removed and any holes filled.)

When the house was bought, the mortgage surveyor found no trace of damp around the patio doors. However, a specialist surveyor did claim to find rising damp. Consequently, the plaster to either side of the doors inside the lounge was stripped off to a height of about a metre, then the walls were treated, coated with moisture-resistant plaster, and given a new top coat of plaster.

Unfortunately, when it rains hard it is not long before a wet patch appears on the fresh plaster near the top of the door's reveal (see

If the rain continues, then the patch spreads down the wall over the hours which follow.

Several attempts have already been made to try and stop the water ingress. Damaged bricks and mortar have had exterior filler applied, while thick waterproof sealant has been inserted above the corballed line of bricks where long-standing crack was present. Although the pattern of the wet patch has changed, water still gets in after a rain storm and shows through the plaster. Obviously decoration of the affected area is impossible until the problem has been fixed properly.

Can anyone in the NG offer any suggestions about what can be done next to diagnose where the water is coming in and how to fix this annoying problem?

Many thanks for reading this posting.

[Bob Mannix]

It's difficult to say without a closer inspection/close up pictures of the exterior around and above the damp area.

One diagnostic you could try is wetting the wall with a hose to a limited height, waiting to see if the damp appears, then trying a bit higher etc. Once the damp appears you have a better idea of where it is getting in and can then narrow the search down a bit.

Expanding foam is for filling gaps and for fixing in position at best. It is not a seal.

[Alang]

I'd take a close look at the mastic around the frame too. It only needs a pinhole to start wicking water through

[Stuart Noble]

What I've done in the past is hack off an inch or so round the frame, and fill any obvious cavities with foam. I then put some greased (25mm wide?)strips of hardboard against the frame and re-render up to them. Slip them out when the render is dry and you have a nice 3mm gap for a bead of low modulus silicone. Not always easy to pinpoint the source based on the position of the damp patches.

[Dave Plowman (News)]

Windows or doors which are flush with the outside of a wall require a good seal between bricks and frame. And between doors and frame too, come to that.

Any foam used for gap filling should be cut back and a cement fillet added between bricks and frame. Then a silicone bead between fillet and frame.

[Alang]

I had one on my bay window when we moved in. Tiny crack in the flashing at one end and water stain right in the middle

[Kipper at sea]

There are two possibilities; the doorframe should be recessed back from the front of the external brickwork NOT flush and covered with a strip of plastic architrave. From looking at the photo, the brickwork above the head of the frame as saged. There should be a steel catnic lintel above the frame and the brickwork realigned. I would as one of the other mailers suggests, use a hose pipe and spray the brickwork above, as this is the other weak spot for the ingress of rain.

Keith

[Mark]

I think the water is coming down inside the cavity from the window above.

-

[Bob Mannix]

It's one possibility - how you can say that that is what *is* happening from the photos is a mystery to me!

[David Chapman]

Very many thanks to those who have already taken the time to reply to my posting and to any other readers who will be doing so.

Your suggestions are most useful and gratefully received. In due course I'll report back to this group on what progress we've made.

ATB - Dave

[Mark]

at

were manufactured to the

(see

 If the rain continues,

IME older houses often did not have a lintel above windows and doors and relied on the wooden door/window frame to support the wall above. Modern replacement windows/doors often are not as strong as the original and sagging occurs.

[mail]

It seems to me that this is a leak from outside and up (obviously) and that the likely route is some form of conduction with mortar from a concentration outside Is there a drip from the render above when it rains that is concentrating the water to a point? Have you considered a bell mouth or the like at the bottom of the render on the first floor? this should entirely cover the corbelled brick which is most likely to be the problem Failing that - a lead cover flashing

chris

[zaax]

Actully that what I thought. The damp starts in the middle of the plaster. It might be running down to the lintel and then across the lintel and as the lintel over laps the end brick it might some out a bit lower down. Also it comes down the outside and getting in between the cement and lintel and coming / wicking across