The latest findings are likely to add further delays to the project

Bath and North East Somerset Council has been told that the same problem may occur on other floors.

Councillor Nicole O'Flaherty said: "We don't know yet whether it is a design or construction fault."

The findings are likely to add to the delays in the troubled project which is two years behind schedule and costing twice the original �19m estimate.

Ms O'Flaherty said: "It is the responsibility of the architects to ensure that the building is constructed and passed to the council completely up to standard and in full working order.

"Therefore, we expect Nicholas Grimshaw and Partners to let us know without delay what they plan to do to put the problem right."

Mowlem is committed to the success of the Bath Spa but can neither predict nor influence the completion date Mowlem statement

"We are working with all parties to address the faulty work and will continue to do so until the project is completed to our satisfaction," it said.

A row over peeling pool paint has caused much of the delay over the opening of the spa.

Meanwhile, contractor Mowlem issued a statement denying it was responsible for the steam room leaks.

"Mowlem does not accept that it is responsible for the leaks in the steam room floor(s) at Bath Spa, but believes there is a design problem," it said.

"We, like the council, now await instruction from the designer, Grimshaws, to enable us to progress the works.

"Mowlem is committed to the success of the Bath Spa but can neither predict nor influence the completion date because it is wholly dependent upon instructions still to be received from Grimshaws."