Mystery damp

[fenchel]

I hve found damp in my upstairs boxroom, covering about 4 courses of brickwork,on an outside corner.Any ideas on cause and remedy-the outside brickwork seems fine.

[nonomaybe]

First , if you have a rainwater down pipe on that corner, check that it's not leaking or overflowing .Secondly check the pointing in that area, to see if it needs renewing."seems" may not be the case.

[beejay1124]

also check if any tiles/slates in that corner or further up the roof are damaged

[fenchel]

Thanks for advice.No pipes,broken pointing or loose slates.The damp is from floor level up(but not coming up through floor)

[nonomaybe]

If everything outside is hunky dory we then look inside, the obvious culprit would be a water source adjacent to the problem area but you would have mentioned that. Have you had a one-off spillage in the boxroom that has soaked into the wall?

[fenchel]

Thanks for advice but no spillage.It's weird-about 4 bricks up,8 bricks in depth and about 3 feet long.Any more ideas gratefully accepted.

[nonomaybe]

Dry the area then see if it comes back, cos every possible cause seems to have been discounted.

Where are the building experts when you need 'em?

[beejay1124]

possibility---if you have cavity wall and it isnt insulated-something may be lodged in the cavity allowing damp to 'bridge' over from the outside skin