I am working on a house with a small bathroom on a west-facing wall with a window and sandwiched between a bedroom to the south and a bathroom to the north:
The outside west-facing wall is made of brick and looks like this (and was recently re-rendered after this photo was taken in 2021):
The south wall is also brick and the north wall is lath and plaster.
The bathroom was fine from 2017-2019 with the walls and paintwork in good condition:
However, at some point in 2020 the walls got very damp and discoloured, paint flaked off and the effloresced.
South wall:
Details either side of toilet:
Ceiling:
This is the current state of the whole bathroom:
Despite the very poor condition of the walls, this does not seem to have got worse in the last 4 years. However, the wall is still very damp in places.
The west and south walls and the ceiling are still very wet when measured with a damp-meter:
Here's an animation showing a "dampmap" of the south wall. The darker the blue the damper the brick under the paint:
The dampest parts are in the top left corner and forming a rough diagonal line going up and to the right.
Here's a "dampmap" of the same projection looking at the south wall also showing the ceiling above and the right side of the west-wall on the left.
Wall:
Dampmap:
I don't know where the water has been coming from.
The other side of the south wall (inside the bedroom) shows no sign of water ingress.
The loft space above is bone dry and the continuation of the brick wall into the loft is also very dry. The lead flashing above seems to be in good condition too.
Could this all have started coming in very quickly in 2020 and caused all this damage before the exterior wall was re-rendered in 2021? The worst parts of both walls and ceiling are still very wet.
The external wall looks like this:
There is also a small horizontal crack above the lintel of the window. Could water be getting in here:
The whole room needs replastering but I'm reluctant to do anything unless I can be sure no more water is getting in.
