Other than airflow or spending loads on heating, nope. I use the HG mould killer stuff, gets rid of it quickly. Your board will smell of chlorine for an hour or two after. https://www.tesco.com/groceries/en-GB/products/301947329
I've thought about getting a solar powered fan/vent thingy as my shed woodie has similar issues, not done it though. I painted the ply with outdoor protective paint and that has helped. Other than that I keep it at bay through regular use, numerous vents and the odd bit of bleach spray/sanding.
It's made of limestone, just single walled.
Quote from: monkey boy on February 16, 2024, 06:08:20 pmIt's made of limestone, just single walled.Oh . Can you knock up an open fire and chimney? Yeah that'll be letting a bit of moisture/damp through especially if its lime mortared.
Worth saying I've tried a dehumidifier in mine and it made no difference, even using a decent size mains based one. It's not a sealed space