I’m curious to see if anyone else has run into a situation like this.

We have a concrete deck all around the second floor of our Library.

The outer perimeter of the deck is cantilevered over the walls of the first floor.

Underneath the deck concrete is a geo-composite drainage board.

Underneath the drainage board is an EPDM membrane to catch any moisture and divert it to the drain.

Underneath the EPDM is tapered insulation.

The topping concrete has a history of spalling and eroding.  All patching and coating products have failed.

I’m realizing now that it’s likely that all products will fail since the drainage board will always be a source of vapor/moisture underneath the topping.

An EPDM membrane between the drainage board and the topping could prevent the vapor transfer, with the drainage board there to catch water from any leaks.

Except that would give me a water build up under any cracks at the control joints.

I’m thinking I should have all the topping concrete removed and use pavers or build a composite deck structure.  This would all be above a drainage board and/or membrane.

I’m open to any and all ideas that will lead to a solution.

Thoughts?

Brian