A foldable Japanese shikibuton for a small home on the Isle of Man: measure the sleeping and storage spaces and plan somewhere dry to air it. Check whether the room also permits lifting and underside drying before deciding that folding solves the space problem. A permanent floor position still needs that care.
How should I plan a shared-use room?
Lay out the usable sleeping dimensions and the furniture you will keep in place. Then identify a position where the futon can be raised after sleep. Measure the dry storage area separately; it should not be the only place available for airing.
What if I cannot make room for that routine?
Consider other bedding arrangements before ordering, or tell us about the support and storage restrictions. The aim is a setup you can use comfortably and maintain, rather than folding a damp mattress away simply to recover the floor.