What to put behind beadboard for moisture control?

gilliweed

I want to cover parts of my conservatory in beadboard. My conservatory has dwarf walls for the most part, built onto the (painted) brick of the back of the house. One whole side of my conservatory is like faux-windows or blanking panels I guess - it’s laid out like the same frame as the windows but where glass would be is UPVC. It’s an unheated conservatory and does have a bit of a mould problem (got a new dehumidifier for this winter which I’m hoping will help).

I want to glue up beadboard to cover everything ugly and then put proper skirtings on. But I’m not sure what I need to put behind MDF beadboard to make sure it doesn’t instantly mould. Or should I use UPVC beadboard in the first place? 

FreeBear

Some form of insulation (e.g. Celotex) behind the board will raise the surface temperature slightly. It might be enough to reduce condensation and the formation of mould. Use a foil faced insulation board, and you won't need to worry about using a vapour control membrane. But what ever you do, I suspect you will still get mould growing behind the insulation and bead board.

gilliweed

I feel like it's not the end of the world to have a little mould behind the board. It's not a room I inhabit generally, and it's due to be knocked down as soon as I can afford to do so! So I'm looking for a solution to make it more pleasant but not necessarily aiming for perfection.

I'll have a look at Celotex, thank you!