WATERPROOFING: TORCH-ON VS. LIQUID APPLIED MEMBRANE (Types and Advantages)
Torch-on or liquid applied membrane? This is a question frequently being asked by engineers, building managers contractors and even homeowners. They both have their benefits but what is the difference really? Below we have discussed the differences between the two and some of the benefits they can bring you.
Bitumen torch-on waterproofing is a blend of bitumen and polymers, which are applied to a polyester or fibre-glass reinforcement membrane. It is an exclusive and specific waterproofing solution that works especially well on flat concrete roofs, where trafficable areas are required, foundation and retaining walls, flashings, parapet walls, expansion joints, corrugated and IBR roof laps and roofing screws, as well as gutters, flower boxes and water retaining structures. Torch-on is best known for being a stronger and sturdier membrane which is generated to keep surfaces safe from damp and water. As it is a waterproofing action, it averts the danger of logging water through its water-resistant surface. Some advantages of bitumen torch-on waterproofing are as follows:
Compatibility with all types of flat roofing applications, but can also be used to waterproof car park decks, bridge decks, green roofs etc.
Resistance to the most extreme weather conditions such as high and low temperatures, rain, snow, ice and the freeze-thaw process.
Life expectancy of bitumen membrane is remarkable, even after ageing it retains its pliability and elasticity, making it the ideal flat roof solution.
Dimensional stability is provided by the high quality bitumen blend together with a high performance reinforcement, enabling the waterproofing system to accommodate building movement.
Installation is simple and can be achieved through a variety of methods; torch-applied, mechanically fixed or adhered, depending on the specification and suitability.
Security and peace of mind for the building owner is achieved through the installation of a robust, multilayer, built up felt modified bituminous waterproofing system.
High resistance to mechanical damage and puncturing in comparison to alternative flat roof coverings. Extreme resistance variants are available depending on the traffic requirements of the surface.
Excellent adhesion to the substrate on a flat roof installation (demonstrated by peel testing)
Quality control is increased when installing factory produced rolls of modified bitumen.
In most cases, when a bituminous flat roof system reaches the end of its service life, a single layer overlay can be installed over the top of the existing system to extend and renew the longevity of the waterproofing system.
Liquid applied membrane, in this case we will be considering liquid applied polyurethane, is a procedure by which a liquid waterproofing agent is applied to a surface that requires sealing. As presented in the name, this method of waterproofing is sprayed or rolled on, usually by a qualified artisan. The preferred method is to use a spray gun but the beauty about the product is that it has versatile methods of application. The waterproofing agent exits the gun and is applied as a liquid form, but dries into a pliable, blocked membrane that water just cannot enter through. Here are some benefits of this wonderful and fairly new technology:
Seamless. The liquid applied polyurethane is applied cold which also takes away the risk of fire when using torch-on.
Applied by spray gun for speed and consistency.
Highly UV Resistant.
VOC water compliant.
Excellent adhesion.
Water vapour permeable.
Bitumen vapour permeable. This means one can apply directly over sound torch-on bitumen systems, without the added cost of stripping, barring the state of the torch-on.
Highly elastic. This allows for expansion during the seasons.
Comes in an array of colours to match your building.
The system is liquid applied that can be used with a fibrous membrane imbedded into the polyurethane system that can increase the life span of the product.
It can be applied under tiles, allowing tiling directly over the system
Application can be applied on horizontal and vertical surfaces.
It is great for patch repairs, where mechanical damage has occurred.
One component application – out of the both, ready to apply when no membrane is required.
Easily recoated. There are also no inter-coat adhesion issues.
The guarantees on the liquid applied membrane products are significantly longer than torch-on, with only one maintenance coat after five years. Torch-on requires three maintenance coats over the same period.
Easily applied to multiple surfaces. These surfaces being ceramic tiles, wood, cement, plastic, metal, brick and bitumen coatings.
Suitable for light trafficable areas.
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