My mother in law is having some work done in her house. There is water getting in around one of the bedroom windows, its in a cavity wall, the builder has told her that the window is too far back and needs removing and refitting futher forward (and that in that case she might as well have a new window).
Is this BS? The only reason I can see for the position of a window being a problem in this way would be if water was running down the cavity.
Is it normal for water to run between the walls?
You don't say the age of the property or type of window. But on most properties (with a cavity) built before the mid-fifties early sixties, the window would have been fitted behind the brickwork reveals of the outer skin of the cavity (usually box-frames [sliding sashes[) and it was normal to put a compo pointing between the window frame and reveal.
When the 'new fangled' EJMA windows (casements to you and me now) came in to popular use after the war, builders started installing them between the reveals of the walls - saving material, time and hard cash.
Don't be bullied into a window renewal (unless it's obviously rotten) - find the cause of the leak first.
In a nutshell yes, that's what a cavity is designed for, as bricks can be rather porus. In MIL's case, I would start by looking at the eaves of the roof as any leak here could cause water to drop into the cavity, landing on the cavity tray that's over the top of the window (or should be) and running back into the inner skin - or simply running down the inner skin (not good or normal).
While you're at that level having a gander, check to see if any weep holes are blocked in the tray area, if they are, prod 'em clear.
You could also check the joint between the window and brick reveal, as any leak here may be able to track across the cavity if the dampcourse between frame and wall has failed (water can also penetrate the brickwork and do the same) - and fill any open joint with a bead of mastic.
If you can see no obvious reason for the pproblem (and there are no holes in the brick bed-joints or reveals), then give a few square metres of brickwork around the window a few coats of liquid silicone - this can stop water running through porus bricks.
Just a few suggestions to look at first.
Woodworm
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.