Large wet patch on exterior wall

8 Aug 2017
Reaction score
United Kingdom
Hoping to get some suggestions for a friend of mine.

He has sent me some photos of the exterior of his house where there is a large wet patch visible on the bricks. He has recently had the soffits and gutters replaced along, also the loft insulated. However, although the wet patch is particularly bad at the moment, it apparently was visible before this work was done. Contractor who did this work has since returned to check everything over and could find no issues with the work done.

The interior wall at this point is also showing damp patches.

Although we have had a lot of rain recently, I feel sure it wouldn't be caused directly by the rain.

The contractor has suggested taking out some of the bricks to investigate, but I imagine this would be a major job.

Has anyone got any thoughts as to what could cause this wet patch? My only suggestion is to leave until the spring summer, to see if it dries out naturally. If it doesn't then there must be a a leak somewhere.

The house was built in the 1970's. The door visible in the picture is to an extension added 15 years ago, The ground floor window is in the kitchen. A wall mounted gas boiler is located to the left of the door (looking from the outside) and I believe pipes to the boiler do come and go from the right side of the door.

Other points: There is a drain just below the hosepipe reel, which I understand runs clear.
The 3rd photo is above the kitchen window and the gap between the frame and the bricks is deteriorating.

Any ideas greatly appreciated.

20201230_103742.jpg20201230_103750.jpg 20201230_103807.jpg
Sponsored Links
Its water in the cavity

Toilet or tank overflow pipe in the cavity?

When the fascias were done, were eaves trays fitted, or eaves felt ripped?
Thanks for the quick reply.

So do you think water is getting into the cavity, from above (possibly from a overflow pipe or from the eaves), which is then causing the dampness to rise up the wall?

Water is sitting on the window lintel, and potentially if the cavity is insulated or blocked, soaking into the insulation/mortar to keep that area damp and also soaking down the corner.

Have some holes drilled into two vertical joints (one brick in from each side) just above the window lintel to form weep holes, as a quick fix to see if it drains. But the source will need rectifying too.
Sponsored Links
Thanks again.

Do you think there any other possibilities for water to get in the cavity to such a degree, other than via the eaves or an overflow pipe? A bath runs above and along the window wall which is showing most of the damp. The side of the bath panel has been removed and no leaks are visible so we are thinking that water is not likely to get into the cavity from any potential bath leak.
Any pipe leak from within the room would show within the room first. A pipe would need to be in the cavity to cause that and not cause damp internally

If there are a few dry days see if the staining reduces in intensity but it may take a good few days or over a week to diminish. Or if it stays damp then, that would be more likely a pipe leak.

TBH, if this happened after the fascia work then that is the main suspect

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local