Torch Membrane Waterproofing: Types, Materials, Standards, Application, and Benefits

Written By Adam Paul - Waterproofing Expert

Torch membrane waterproofing is a waterproofing method used to create a water-resistant seal by sticking on the surface using a gas torch. Torch membranes can be used to waterproof roofs, balconies, basements, decks, garages, green roofs and planter boxes.

Torch membranes are mainly two types: APP (Atactic Polypropylene) modified bitumen torch membranes and SBS (Styrene-Butadiene-Styrene) modified bitumen membranes. Torch membranes consist of adhesive material and fabric. Bitumen and polymer modifiers are the main adhesives and polyester and fibreglass mats are the main fabrics used for the torch membranes.

You should check whether the torch membrane is followed by the international standard (EN) before you use it. You should heat torch membrane between 392℉ ( 200℃ ) to 482℉( 250℃) when it is installed on the floor.

You should heat 1.5mm thickness torch membrane waterproofing for 30 -45 seconds per square meter. If the thickness is around 3mm, the membrane should be heated 45- 60 seconds per square meter. You should heat the torch membrane while itis unrolling before laying it on the substrate.

When you install torch membranes, you should maintain longitudinal lap length between 50 -100 mm ( 2- 4 inches), and transversal overlap length between 100 - 150mm (4- 6 inches). You can install a torch membrane on a dry day with temperatures between 50℉(10℃) - 86℉(30℃). You should use proper tools for torch membrane waterproofing.

When you fillet the torch membrane, the distance should be 85mm overlap. Over the fillet, it should be 25mm, while below the fillet, it should be 100mm. You should install a torch membrane in calm wind and proper environmental temperature. Because calm wind is very suitable during the installation to heat the membrane uniformly.

Installing torch membrane is always durable and lasts long, about 10-15 years. It is highly water resistant, resistant to sunlight, rain, wind, and extreme temperatures, can be installed quickly, has higher flexibility, improves energy efficiency and consists of self healing capability.

What Is The Torch Membrane Waterproofing?

Torch membrane waterproofing is a waterproofing method used to create a water-resistant seal by sticking on the surface using a gas torch. Torch membranes can be used to wateproof roofs, balconies, basements, decks, garages, green roofs and planter boxes. Torch membrane waterproofing consists of bitumen, a petroleum-based product modified with polymer.

When installing the torch membrane, first clean the surface, then apply the primer coat, unroll and position the membrane with overlaps for a strong seal, and heat the membrane's underside, melting it to fuse with the surface and overlaps. Torch membrane waterproofing is durable, long lasting, water ingress, and easy to install on the surface with minimum labor and time.

What Are The 2 Types of Torch Membrane Waterproofing?

The two types of torch membrane waterproofing are APP (Atactic Polypropylene) modified bitumen torch membrane and SBS (Styrene-Butadiene-Styrene) modified bitumen membranes

APP (Atactic Polypropylene) modified bitumen torch membranes: APP consists of atactic polymers. These torch membranes are highly flexible and can withstand higher temperatures. Hence, APP can be used to waterproof structures such as roofs, terraces, and balconies with higher UV exposure and higher temperatures.

SBS (Styrene-Butadiene-Styrene) modified bitumen membranes: SBS consists of modified SBS polymers. These torch membranes are elastic and flexible and perform well in cold temperatures. It can be used to waterproof structures where in cold climates with frequent temperature fluctuations.

Read more: What to Know About Bituminous Waterproofing Membranes?

What Are The Main Materials For Torch Membrane Waterproofing?

Torch waterproofing membranes consits of two main materials such as adhesive and fabric. Adhsive is used seal the substrate while fabric support the adhesive to stay remain on the substrate.

1. Bitumen: Bitumen is the adhesive of the torch membrane waterproofing because bitumens are natural waterproofing with strong adhesion ability, durability, flexibility, and cost-effectiveness.
2. Polymer modifiers: Polymer modifiers are adhesive material of the torch membrane and it used for torch membrane waterproofing due to flexibility, heat resistance, durability, and higher adhesiveness.
3. Polyester mat: Polyester mat is used as a fabric in the torch membrane. It is used due to its high stability, resistance to wear, tear, puncture, and warping capability.
4. Fiberglass mat: Fiberglass mat is used as a fabric in the torch membrane. Fiberglass mats consits of higher resistance to wear, tear, puncture, flexibility, and warping capability

What Are The Recommended Standards For Torch Membrane Waterproofing?

Below are the properties and their recommended standard for the torch waterproofing membranes. This table is prepared by using European Standards (EN).

What Is The Heated Temperature of Torch Membrane Waterproofing?

The recommended heating temperature of torch membrane waterproofing ranges from 392℉ ( 200℃ ) to 482℉( 250℃) when it is installed on the floor.

When it is lower than the recommended heating temperature, the membrane will become uneven, and burning creates inconsistent seams, reducing flexibility and improper adhesion.

When it is above the recommended temperature, the waterproofing membrane will overheat, causing blistering, burn, degrade, and fire risks.

How Long Should You Heat Torch Membrane Waterproofing?

The heating time of the torch membrane depends on factors like membrane thickness, ambient temperature, wind speed, and desired outcome.

You should heat 1.5mm thickness torch membrane waterproofing 30 -45 seconds per square meter. If the thickness around 3mm membrane should be heated 45- 60 seconds per square meter.

Overheating the torch waterproofing membrane can cause blistering, burning, and degradation, generating fumes, odors, and fire risks.

Underheating the torch membrane waterproofing can weaken the adhesion, reduce flexibility, cause uneven melting and burning, and cause inconsistent seams.

What Is The Heating Pattern Of The Torch Membrane Waterproofing?

When you heat torch membrane waterproofing, you should heat the membrane while it is unrolling. When you start from the left, heat along the membrane and then roll down the membrane to the substrate. Then, start it from the stopped end to the other end.

What Is The Lap Length For Torch Membrane Waterproofing?

Longitudinal lap length ranges between 50 -100 mm ( 2- 4 inches), and transversal overlap length ranges from 100 - 150mm (4- 6 inches).

What Is The Suitable Environment For Touch Membrane Waterproofing?

You should install the torch membrane on well dry day with temperatures between 50℉(10℃) - and 86℉(30℃). You should not use torch membranes on higher humidity and wet surfaces due to lack of proper adhesiveness.

What Tools Are Needed For Torch Membrane Waterproofing?

1. Safety glasses and gloves
2. Propane torch
3. Cutting tool
4. J - roller
5. Smoothing trowel
6. Seam roller
7. Thermometer
8. Drop cloths

What Is The Fillet Overlap Distance Of The Torch Waterproofing Membrane?

Fillet overlap distance is 85mm. Fillet overlap distance depends on the membrane type, water pressure, and waterproofing membrane thickness.

What Is The Distance Over The Fillet Of Torch Membrane Waterproofing?

The distance over the fillet of the torch membrane is 25mm. The distance over the fillet depends on the manufacturer’s recommendations, wate pressure, and waterproofing material thickness.

What Is The Distance Below The Fillet Of Torch Membrane Waterproofing?

The distance below the fillet of the torch membrane is 100mm. The distance below the fillet depends on the manufacturer's instructions and professional advice.

When Should You Install Torch Membrane Waterproofing?

You should install torch membrane in calm wind and proper environmental temperature. Because calm wind is very suitable during the installation to heat the membrane uniformly.

You should not install in climatic conditions such as freezing temperatures ( below 50℉), extreme heat, high humidity, and rainy or snowy conditions.

What Are The Benefits of Torch Membrane Waterproofing?

These are the 7 benefits of torch membrane waterproofing

1. Torch membrane waterproofing is durable and last for about 10-15 years
2. Torch membrane waterproofing is highly water resistant and creates an effective barrier against water intrusion
3. Torch membranes are resistant to weather conditions such as sunlight, rain, snow, and extreme temperatures
4. Torch membrane application can be completed quickly
5. Torch membranes are capable of self-healing
6. Torch membranes are good thermal insulators and improve energy efficiency
7. Torch membranes act as a barrier against radon gas intrusion

Where Can You Use Torch Membrane Waterproofing?

You can use torch membrane waterproofing membranes for below structures

1. Flat roofs: Torch membranes are ideal for flat roofs because they create a seamless, water-right barrier.
2. Balconies and decks: Balconies and decks often cause water damage. Torch membrane waterproofing provides a durable layer that can withstand water damage.
3. Basement and foundation: Basements and foundations like below-ground areas build moisture and cause moisture-based issues. Torch membrane waterproofing effectively causes water seepage and moisture build-up in below-ground areas.
4. Plaza decks: Plaza decks, often on top of buildings or car parks, need a strong waterproofing solution. Torch membrane can handle the weight of foot traffic and protect the underlying structure from water infiltration.
5. Retaining walls: Retaining walls hold back soil and can be prone to increase the water pressure. Torch membrane waterproofing helps ensure the wall's stability by preventing water accumulation.

What Are The Disadvantages Of Torch Membrane Waterproofing?

1. Torch membrane waterproofing causes fire hazards during the installation process.
2. Torch membrane waterproofing is only suitable for surfaces that can withstand high heat.
3. Torch membrane waterproofing membrane emits harmful gases during the installation, causing environmental pollution.
4. Torch membranes deteriorate when exposed to sunlight.
5. Torch membranes do not conform perfectly to uneven surfaces.

What Are The Options For Torch Membrane Waterproofing?

1. Liquid Applied Membranes (LAMs): You can use LAM instead of torch membrane waterproofing because they don’t need flames during installation, can be applied on a wide range of surfaces, and have self-healing properties.
2. Self-Adhesive Membranes: You can use self-adhesive membranes instead of torch membranes because they are easy to install, take less time, and have no fumes released during installation.
3. Sheet membrane: You can use sheet membranes instead of torch membranes because they are cost-effective, lightweight, flexible, and durable.