Warm air vapour condenses on cold lintel

[earnshaw]

Please see diagram below:



This is basically what is happening in my house - I have a brick lintel which is both inside and outside the house - so it is exposed to the cold air outside and when you touch the brick inside the house it is also freezing.

The annoying thing is - whenever it is warmer in the kitchen - or you cook something, the vapour in the air condenses straight away on this lintel because it is so cold - and it gets really wet - even dripping, this is staining the paintwork around it and making an unsightly mess.

Bear in mind this is Yorkstone - very old house - what is the best way to stop water condensing on the lintel? Are the some repelling treatments available? Should I insulate it with polystyrene - and plasterboard - and box it in and plaster over it? Or will I still get problems? Any experts out there who can help - reallly, really, really appreciated - as I have no idea what I can do to stop it!

[ultimatehandyman]

Nice picture

My mate has a similar problem but I think his problem is penetrating damp, rather than the condensation problem that you seem to have.

I'd get some thermal plasterboard and then I would cut it to the correct shape and then glue it to the lintel using silicone sealant, it will require proping in position until the sealant sets fully. If the problem goes away you can pull down the plasterboard by cutting through the silicone bead with a hacksaw blade and then redo it using dry wall adhesive, then skim over it and paint it.

I would not advise using dry wall adhesive for the test as it is extremely difficult to remove.

Here are some pages that might help-

dot n dab

plaster beading

plaster skimming

[earnshaw]

Sounds like a plan - I will look into doing this on Friday - I will let the forum know my results in due course.

Cheers.