GreenTips

Tanking and waterproofing are important lines of defence in buildings. A good quality system will increase the durability of the building itself. An excellent source of information on the use of tanking and waterproofing can be found at the British Structural Waterproofing Association.

Many waterproofing treatments are fully adhered, making them difficult to separate from their substrate during demolition.

The majority of materials used for tanking and damp proofing are solvent based. As a consequence, they release volatile organic compounds into the atmosphere during their drying process. VOC’s are known contributors to smog, especially in the production of ozone that is a corrosive and unwanted gas in the lower atmosphere. Applied membrane systems also commonly use solvent based primers, which again off-gas VOC’s.

Bentonite clay tanking systems are an exception to the rule. They are a high quality natural product, that takes advantage of bentonite clay’s ability to expand in the presence of water.

Some manufacturers have been developing water-based products which contain no VOC’s in response to (overseas) regulations on VOC emission limits. It is possible that these alternatives offer the same protection as the solvent based products and are worth investigating.

A number of tanking and waterproofing products also contain chemicals that can be harmful to human health. In particular, the hot application of bitumen/mastic and the spray application of other man-made chemical damp proof membranes should also always be treated with care.

Super insulated buildings enclose the building in an airtight layer of building wrap. This minimises the ventilation heat loss through gaps in the construction, improving the thermal performance dramatically. As buildings become better sealed more consideration needs to be given to ways to ensure that enough controlled fresh air reaches the interior to ensure a healthy environment is maintained and to allow unwanted moisture in the structure to dry out.

Building paper and roofing papers are often bitumen or solvent based. Some believe that emissions from these materials can cause poor air quality in buildings. A number of companies now produce solvent free building paper in both light weight and heavy duty designs.

The use of foil based building wraps can result in a significant reduction in heat loss. The foil acts to reflect heat back into the building. When used in roof construction these foils can also reflect unwanted solar gains out of the building and reduce overheating.

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