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Alang Alang is offline
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Default Water ingress problems around French windows.

On Thu, 19 Feb 2009 16:14:50 -0000, "Bob Mannix"
wrote:

"David Chapman" wrote in message
...

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
http://www.minda.co.uk/dave/HouseBack.jpg) 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
http://www.minda.co.uk/dave/WaterIngress.jpg). 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?


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.


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