THE PROBLEM
Dirty water from leaking plant and equipment was leaking through the slab and entering clinical areas below, preventing a hygiene risk and causing additional cleaning/decontamination costs.
THE SOLUTION
We proposed the construction of several bunds to contain the leaks and the application of a seamless flexible bund lining/waterproofing system.
Preparing for the Bund Lining
Initially all surfaces were prepared by method of vacuum controlled diamond grinding to remove the poorly adhered existing coatings to ensure excellent adhesion of the new bund lining.
Building the Bund
Once prepared bund walls were constructed using concrete blocks bonded to the slab using a high strength epoxy mortar made by combining sand and resin at a ratio of 5:1. The same mortar was used to create a fillet detail at the floor/wall intersection to isolate this potential point of movement from the new bund lining/waterproofing.
Applying the Bund Lining
Any cracks in the slab were first sealed using a flexible polyurethane jointing compound prior to isolating from the new bund linings using a bond breaker tape. These areas were then reinforced locally using a chopped stand matt incorporated into the epoxy primer.
To ensure a seamless and pin hole free bund lining the new bund walls received a cementitious grout coat to remove the profile from the concrete blocks.
The bunds were then primed using a damp tolerant epoxy primer to ensure excellent adhesion of the new bund lining/tanking system. This was reinforced over the cracks using chopped strand matt for additional strength.
Finally two coats of a flexible polyurethane coating were applied throughout to a thickness of 1mm to create a seamless and flexible lining. Because this material can crack bridge in excess of 100%, any movement which could occur should be accommodated by the lining.
As a finishing touch the tops of the walls were marked in safety yellow to highlight the trip hazard of the bund walls.
