So if there’s a moisture buildup inside your Summerhouse then it is going to be vulnerable to mould and rot buildup internally. You need to make sure that you’re doing the right things to stop that from happening. It’s very straightforward. And it just needs a good air out every now and again. Make sure that you’re painting the outside of the building. And make sure that you’re opening up the windows and the doors periodically to let it get a nice airing right through.