It's an external cavity wall in the kitchen
Wall has been dry up until today.
It is a 1980's extension on back of Victorian house and has previously been damp proofed.
To narrow down what the cause could be can anyone help confirm the following :
If it's wet after torrential rain does this mean it's likely not to be rising damp?
The external wall is rendered, can't see any cracks - does this mean it's likely not to be penetrating?
If these two points are correct,
I'm guessing to be dodgy bit of guttering or something to do with the block paving going up to the wall on the outside.
I was watching the rain today and the rain wasn't sitting against the house, so possibly not draining away properly underneath?
Should I take up one course of block paving bricks to see if that helps?
We are forecast rain for the rest of the week.
Additionally - there is no smell of damp and no mould
Some of the paint above skirting is slightly bubbly now