All of the Wooden SPA Solutions models can be used in any environment, but in all cases it is important that the surface supporting the room is firm and level (a slight taper for rain run-off is fine.) Suitable surfaces include wood decks, concrete patios, paver stones, pressed gravel, etc. The Barrel can be placed directly on the ground due to the synthetic plastic cradle supports, which create a barrier between the red cedar and the bare ground.