For a design project, we're looking to use XPS foam boards that are 5cm thick (15 cm wide strips) to support the underside of a bath without legs or wall fixtures, but a supportive frame at each end.
The bath is steel enamel with a slightly curved underside and will be supported by 4 layers of XPS.
Will the XPS foam be able to withstand this kind of pressure with regular use?
Intuitively, we were thinking several thicker boards would be superior in terms of pressure resistance rather than many thinner boards, but please advise otherwise if this is incorrect.
Best Answer
It depends on what you mean by "support". It will hold the tub up but it will flex. The movement of the flexing may loosen plumbing connections ; not the first time , but movement over an extended time could work things loose. It may even cause leaks at what ever caulk or trim is used on the top edge of the tub.The weigt of 6" water in a 5' tub is roughly 300 lb. plus occupant(s).