Anthony Nolan Bone Marrow Appeal Laboratories, Royal Free Hospital, Hammersmith, London

The basement of this newbuild property was tanked with adhesive sheet membranes within the cavity construction and concrete floor, but soon flooded. Subsequently, a second cementitious tanking system was applied to the inner surfaces of the walls and upon the floor.

The picture here shows the writer, George Hockey, examining the cementitious tanking screed in June 2000, that had heaved and cracked because of ground water pressure causing heave, with free lime escaping from the cement used.

Repair proposals were put forward by Trace Basement Systems^TM, involving Basement Systems WaterGuard^TM drainage channels and dual mains powered and battery backup UltraSumps^TM, with Platon 8mm profile P6 cavity drainage membrane and 22mm profile Weyroc PFB plastic coated waterproof chipboard over.

Although there was no evidence to indicate that water was escaping anywhere but through the floor and at the wall and floor joints, a 150mm skirt of Platon P6 was applied to the walls, forming an upstand at all walls, including internals.

This was applied just in case water does eventually penetrate through the external walls at higher level, although now that ground water pressure is relieved by the WaterGuard^TM channels, there is significantly less chance of that ever occurring, the role of the two failed tanking systems on and within the walls being downgraded to that of a vapour barrier and drainage conduit rather than having to work under pressure.

The WaterGuard^TM was only fitted at the external walls, thus encompassing the most vulnerable locations. Two  UltraSumps^TM were fitted, one at each diagonal corner of the basement, with the water extract pipes fully insulated to prevent condensation internally and freezing externally.

IceGuard^TM, a unique anti-freezing pipe outlet was also used.

The picture opposite shows highlighted water within the chase cut out to take the WaterGuard^TM.

We fitted service ports within the channels, so that flood tests can be carried out annually, ensuring that the system  remains in working order, which we do under an annual maintenance contract.

Consider what alternative remedial measures may have been necessary had  Trace Basement Systems^TM not put forward Basement Systems WaterGuard^TM drainage channels and dual mains powered and battery backup UltraSumps^TM, with common practice in the UK previously and to a great and ignorant extent, still to attempt to repair failed tanking systems, all at risk of failure the next time pressure comes to bear!

How far would one have needed to go to repair this problem by one of the numerous tanking methods, hoping that the repair would work, rather than in our case knowing that IT WILL WORK because pressure is relieved.

 We have the Americans to thank for this. Larry Jenesky, the President of Basement Systems^TM in Connecticut, is an innovator and inventor, and is supported by over 100 contractors in the USA, Canada and the UK, all using the same products to deal with water problems in basements.

Believe it or not, in America there are millions of feet of WaterGuard^TM in the ground, protecting thousands of basements.

Whilst it is taking time to educate the UK market in it's ability in controlling ground water pressure, it will come to dominate the basement waterproofing market, and will be installed in association with many forms of waterproofing in addition to cavity drainage, with which it works so well.

We have a saying, 'Go Back To The Future with WaterGuard'