Vapour Control Layer

[polkablues]

Has it recently been built as it could just be condesation from the building drying out, we did one a year ago on top of an existing garage and the roof space looked like it had been hosed down it was that wet, took a while to dry out, but fine now !!

It was completed at the start of December, yet to be plastered but there was a fair amount of brickwork and 35m3 of screed floor. I'm hoping it will dry out, what would be a fair amount of "dry out time"

 

[polkablues]

Sounds like a VCL could certainly help but you still need to deal with all the moist air in the room especially, if it is to become a kitchen.
How do you intend to deal with extraction when it is in use?

Also how long has this extension been built? As there will be a masdive amount of moisture released for the first few weeks as concrete/plaster/mortar drys out which could be causing your issues short term

Hi Ian,

There will be a kitchen extractor fitted, it was completed start of December and is yet to be plastered, I'm hoping that it will dry out as there is a fair amount of brick and block work with 35m2 of screed floor. What would you class as a reasonable dry out time. Its also been UFH since December

 

[BigIan]

After a month, I wouldl expect most of the moisture to have gone.
With a mono pitch roof one of the issues you may have is the moist air rising to the high point and having no where to escape to
I would consider looking at some way to increase vetilation or air movement there..