Damp patch has appeared - advice please (photos included)

batman2000

ThisIsWeird said:

As said, that vent is ideally placed to give viewing access. You'll want it gone in any case.

Thanks, I’m frustrated that the vent wasn’t removed during the work (I should have paid closer attention). 

So what trade/expert do I need? And would it be worth taking that patch of plaster back to the wall again in any case? 

stuart45

I'd try to find the cause of the damp first, before hacking off the plaster.

moneysaver1978

Silly question but why does the vent need to go away/removed?

stuart45

moneysaver1978 said:

Silly question but why does the vent need to go away/removed?

It's not a silly question. Leaving it in isn't a serious issue, but it's a simple job to remove. It causes a potential cold spot on the inner wall, and the liner, if it still goes through the wall, could possibly allow any moisture running down the inside of the outer skin to cross the cavity. When fitting them, they should run down to the outer skin, but often they are level. Probably not worth paying £100 to take it out and make good, but if it was my house I'd probably do it if my wife knew it could be an issue.

GDB2222

How thick is the wall? Are you quite sure there's a cavity?

stuart45

If it's a solid wall then the cracks in the render could be causing it.