chipboard flooring

Plywood is better. Chipboard is nasty for a number of reasons, for example it absorbs water easily, and is much weaker. However. If the chipboard you have is thick enough, and you slap some paint/varnish on it, it should be OK.

Surely in a cupboard it will be OK though?? It's commonly used instead of floorboards isn't it (albeit under a floor covering)

David

Probably, depending on the assymetry of the floor, thickness of the chipboard, load on the chipboard. You can get away with a lot thinner plywood than chipboard, as the plywood will flex lots more than the chipboard before failing. Chipboard will probably be fine, as long as it's reasonably thick (>>10mm), and it isn't supported only at the edges. If it can be done, screwing the floorboards down as flat as possible would be a good idea.

Buy some cheap laminate flooring and use that. Much lighter and easily laid.

Dave