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Liquid-Applied or Torch-Applied Sheet Waterproofing Membrane?

Which is the best waterproofing membrane? Is it the liquid-applied membrane or torch-on sheet membrane? This is a common question asked by engineers, homeowners, and contractors we will know its answer in this article.

Firstly, let us know what is meant by each

Liquid-applied membrane (LAM) is a monolithic, fully bonded, liquid-based coating suitable for many waterproofing applications. The coating cures to form elastomeric waterproof membranes and may be applied over many substrates, including asphalt, bitumen, metal, and concrete.

The sheet membrane is a waterproofing membrane that comes in rolls, can be made of bitumen, or synthetic thermosetting/thermoplastic polymers, and is differentiated by the way it adheres on the surface; bituminous can be (torch-applied, self-adhered, mechanically fixed), synthetic polymers which can be Fully Adhered, Mechanically Attached, or Ballasted (loose-laid).

A torch-applied membrane we are discussing today is a sheet membrane made from Bitumen that comes in the form of sheet rolls and its application involves the use of a heated torch to melt the underside of the membrane onto the surface.

9 Reasons and Features Why You Should Use Liquid-Applied Membranes

1. Seamless & joint-free, fill in cracks, gaps, and voids in the substrate

 2. Fast, easy, and safe application as it is one component and cold applied without any fire or heat.

 3. Versatile It can be applied to various surfaces, including concrete, ceramic & cement tiles, metal, bitumen, and brick.

 4. Excellent bonding & adhesion properties, fully adhered to substrate, adhere to irregular surfaces making it an excellent choice to waterproof surfaces with complicated details.

 5. Highly elastic & crack bridging; where having the ability to expand and contract allows waterproofing to accommodate the structural movements of a building or a surface and helps to bridge cracks that may have been caused in the substrate.

 6. High UV resistance and high solar reflectance index when applied in white color, so it is ideal for exposed roofs such as Uniguard HB.

 7. Cost-effectiveness where 1-2 layers are needed and its application easy, fast, and no need to Highly trained installers such as bituminous torch-applied membranes.

 8. Easy repair & maintenance; where it is removable and easy to re-coat. No inter-coat adhesion problems. It’s excellent also for patch repairs in cases of mechanical damage.

 9. Water vapor permeable, and can be applied straight to an existing sound torch-on bitumen system without the need for expensive stripping. (Polyurthane waterproofing such as Uniguard PU 1K can be applied above sound Bituminous membrane).

Perfect for exposed roofs or any surface with several details

Ideal for areas with light traffic.

What about torch-applied waterproofing membranes?

The torch-applied membrane has high durability and resistance to extreme weather conditions like extreme temperatures, low temperatures, snow, rain, and freeze-thaw, in addition to root resistance, but has some drawbacks such as:

1- It is not seamless and requires special attention to joints, seams, and changes in plane. 

 2- Not fitted for all surfaces, the membranes are limited to a maximum width of one meter, and the sheet membrane must be cut and pieced together to suit the size of your space.

 3- Involves multiple layers of the membrane to install and thus increased materials costs and installation will take longer than liquid applied membranes. However, more layers applied in the system do not mean greater waterproofing protection. 

 4- Labor-intensive application process.

 5- Highly trained installers must be used to ensure that the modified bitumen membranes are correctly installed as sheet membranes need to be cut according to different shapes & sizes of the surface, require skillful workmanship to seal the joints & seams properly and do the overlapping correctly.

 6- If a puncture occurs in liquid membranes that are fully bonded to the substrate, and the water leak will be where the puncture occurs. Whereas joins, seams, or overlaps in sheet membrane can debond and potential water leaks can happen and the water leak might be a distance away from the original point of entry, so water leaks can’t be easily identified and repaired and the maintenance process itself is not that simple.

Ideal for a flat roof or low sloped.

 For heavy rainfall or extreme weather conditions.


Overall, Liquid-applied waterproofing materials have several advantages over torch-applied sheet membranes, the most significant of which are ease of installation, simplified detailing, and cost-effectiveness.

A liquid-applied membrane eliminates many of the issues associated with torch-applied sheet membrane waterproofing systems, such as uneven seams, and end lapping. Minor imperfections, small gaps, and irregularities are easily corrected with liquid membranes. A liquid membrane's seamless, monolithic adhesion reduces the risk of failure at joints, overlaps, seams, and changes in plane that may happen in sheet menbranes. Also, the fluid-applied system's elastomeric characteristics will tolerate minor settling and structural movements caused by temperature and humidity variations.

Uniguard offers a wide range of Waterproofing solutions, such as cementitious mortars, in addition to acrylic, bituminous, and polyurthane liquid-applied membranes to suit all project needs.