Tanking a cellar, basement or other underground earth retaining structure?

Tanking and Waterproofing considerations - what is the difference?

An underground structure that has been or tanked (i.e. completely sealed below ground level) will most likely fail if subjected to external water pressures. It is therefore important to get the appropriate waterproofing solution first time!

BS8102 : 1990 is the British Standard for waterproofing of structures below the ground. All those designing a new earth retaining structure or indeed upgrading an existing structure, should be aware of the requirements of BS8102. The whole document is some 38 pages long, and we are therefore unable to represent the document in full. However, we have included some pertinent paragraphs:

"Almost all basement structures are likely to be subjected to water pressure at some period of their life."

"For basements not exceeding 4m deep, a design head of ground water, three-quarters the full depth below ground is adequate".

In layman's terms BS8102 is saying that we should always expect water ingress at some point and that we should expect the water surrounding the basement to be at least the depth of the basement. This is very important as it confirms that one should always waterproof any structure that is earth retaining.

There are three categories of Waterproofing - Tanking (Type A) offering the least protection through to the highest drained protection (Type C)

Type A:(Tanked protection) - The structure has no resistance to water ingress and so requires a continuous barrier applied to the structure.

Type B: (Structurally integral protection) - The structure offers the required protection to the required grade.

Type C: (Drained protection) - Any water ingress is controlled and channeled away from the structure via cavities formed within the walls and floor. For those seeking maximum assurance this combination of construction and waterproofing is considered
the most effective and trouble free.

Newton's Waterproofing Solution:

Being a cavity drain membrane system, Newton System 500 is categorised as Type C. (drained protection) and will offer the highest level of protection from water ingress to your underground living space.

The range of Cavity Drain Membranes within Newton System 500 allow for any water ingress to be controlled, drained and discharged from the structure. When Newton System 500 is fitted to the walls and floor of the structure, the membranes create a dry and habitable inner environment, whilst the waterproofing carries on unnoticed behind the system.

Newton System 500 is quick to install with no heating, mixing or torching required and very little substrate preparation. As well as having superior waterproofing qualities Newton System 500 is much quicker to install than tanking products such as asphalt, dense renders and paint on or sheet bitumastic systems. In many cases, Newton System 500 can be installed in the time it takes to prepare the substrate for tanking that requires damaging processes such as grit blasting and scabbling.

Newton System 500 is chemical free therefore kind to both the internal and external environment.

For more details on waterproofing and tanking considerations and details of our products order our free brochures.

Our pre-sales technical advisers will be glad to be of service and will help advise you on your project. Contact our office to locate the John Newton & Co Ltd registered installers near you.