Much as I enjoy building laser cut buildings, they have not fared well over the years in a garden shed. It is to be expected when the wood is exposed to winter moisture and summer heat. Spraying them inside and out hasn't made much difference. Long term, the station building and goods shed will be replaced with suitable resin structures.
that's a shame as your buildings are lovely. The 7mm station buildings I purchased from you are still in excellent condition, adorning a sideboard in the lounge, pending their permanent home, which still seems some way away. Given the difficulties I have met with building an extension, it looks like I too will have a shed.
MDF is porous, I guess a thorough soaking in something like shellac or sanding sealer before painting would be a good solution to stop them taking on water, but of course that would change their appearance, and the material would then behave more like resin. And, I guess, the suggestion is not much help now.
