MOONBOARD
The space heater under the board certainly works to allow you to have a session on dry holds. However you need to sort it out permanently, as the holds will probably start to grow mold soon and will eventually fall apart. Ply holds are the absolute worst for soaking up moisture. I've done / am doing a few things:- Fit insulation. Bit of a ball ache to do after the board is up but certainly helps create a more stable atmosphere. - Add a foam floor. Gym mat type flooring works well. - Improve the air circulation in the shed. Can do this by fitting air vents in the walls, and / or a whirligig type extractor like you'd see on a van.
I do have a big fan mounted behind the board which does help a lot, I'm just after those crisp training conditions! Don't want to shell out a couple of hundred quid for it to only make a one degree difference in temperature.