Tanking
Polisystem would like to introduce Polisystem Tank PL membrane for use in waterproofing tanks. Polisystem Tank PL membranes have been designed to waterproof in high and low temperatures, and to ensure the longest possible service life even under the harshest conditions.
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 first step is to determine to what use the basement will be put. BS8102 describes four standards of tanking and waterproofing, ranging from the lowest which allows some water ingress, to a totally dry environment.
Once the grade has been selected soil conditions need to be determined, so an assessment can be made as to what levels and degrees of water pressure the structure and it's waterproofing materials will be subjected to.
Only when these factors have been considered can the design of the system and the type of materials be selected. Although in theory the selection and design sounds a relatively simple task, there are many decisions to be made.
An extract from the document states:
"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 channelled 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.
Polisystem Tank PL 1.2mm Homogeneous membrane provides an inert non-toxic waterproofing membrane for such applications.
For more information with regards to your specific application,
please contact Polisystem UK Ltd.
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