Plant rooms contain pumps, motors and tanks, all of which present a risk of spillages. Often in hospitals these plant rooms are situated above clinical areas, which if a leak were to occur have to be taken out of action for significant periods of time whilst the leak is resolved and then the area sterilized prior to being returned to clinical service.
We proposed the application of our proven plant room tanking system to form a waterproof membrane throughout the plant room. When tanking plant rooms attention to detail is absolutely key.
Initially all surfaces were prepared by method of vacuum controlled diamond grinding to remove surface laitance from the new concrete screed to ensure excellent adhesion of the tanking system.
All surfaces were vacuumed clean and as part of our standard quality assurance the moisture content of the slab and the climatic conditions were tested and recorded. The client had introduced indirect oil fired heating to ensure the correct climatic conditions were achieved.
In conventional resin flooring expansion joints should always be reflected through to the finish, however if this were the case in a tanking application this would provide a significant weakness as a single point of failure in the sealant would allow liquid egress from the plant room into areas below.
Our approach is instead a multi layer approach. Expansion joints are first primed using a damp tolerant epoxy primer to ensure excellent adhesion. The joints themselves are then sealed using a flexible polyurethane jointing compound.
Because the joints are going to be overcoated a bond breaker tape is then applied to isolate the expansion joints from the waterproofing membrane. Using a bond breaker tape serves as an elongation multiplier by allowing the membrane to expand and contract over a greater distance. If a material can elongate 25% greater than its original length, 12% of 10mm is only 12.5mm. By applying a 100mm bond breaker tape the same movement location can now freely move 125mm.
The next stage of the tanking process was to reinforce the expansion joints using a nitrile rubber woven sealing tape that can move in 3 dimensions. The nitrile rubber core means that even if the resin membrane were to split, the core of the tape should still remain watertight. This was embedded in the flexible polyurethane resin that would be used later to form the waterproofing membrane. This effectively means that the expansion joints have three layers of waterproofing – sealant, nitrile membrane and the polyurethane tanking membrane.
