Torch on Waterproofing
Bituminous products are perfect for the waterproofing of roofs as they move with the structure, they are not too rigid and do not absorb water.
Waterproofing membranes systems are designed to protect both residential and commercial buildings through a mixed substance made up of organic liquids that are highly sticky and viscous. Bitumen is a hydrocarbon and is created naturally from crude oil, it is a useful carbon store and does not generate greenhouse gases.
Torch-on membrane is a bitumen-based waterproofing product which is heat-fused to underlying substrates. It is sold in a variety of thicknesses with single or dual re-enforcement with polyester or fiber glass.
- Concrete roofs are not watertight on their own. The conventional waterproofing system with membrane is not the answer to your leaking concrete roof. The only way to do proper waterproofing on your concrete roof is to do the Torch-on Waterproofing.
Torch-on is applied to flat smooth surfaces. A flat roof can be made out of a number of different materials, but the most popular include corrugated or IBR sheeting, a solid concrete slab and wood. One thing all three types of roofs have in common is that they all need to have a slight slope from back to front, or vice versa, so that rainwater can run off. However, unlike normal angled roofs, flat roofs tend to be susceptible to leaks and therefore need to be waterproofed and well-maintained to avoid this weakness.
Surfaces must be sound, clean and free from any contaminants and primed with one coat of Bitumen Primer prior to the application of the torch-on membrane. Once cooled, the membrane should be protected with 2 coats of Bitumen Aluminium Paint for UV protection or covered with a screed and tiling. Care should always be taken to ensure good overlaps between rolls and to lap side walls to prevent water ingress.
Bitumen remains the most important base material for waterproofing today, this despite the fact that dozens of “miracle” new products have come on to the market. Bitumen is inexpensive, inherently waterproof, durable, has excellent adhesive properties and is non toxic. Examples of five thousand year old applications of bitumen exist in the middle east. No other system has this track record as a waterproofing agent. Unmodified bitumen has the disadvantage of being brittle at low temperatures and soft or liquid at high temperatures. Flexibility and flow resistance over a temperature range of zero to ninety five degree centigrade is a prerequisite for South African conditions.