Ultimate Guide for Bituminous Coating Waterproofing

Bituminous coating waterproofing is a protective layer applied to surfaces to prevent water ingress. It is made of bitumen, a petroleum-derived hydrocarbon. It is modified with some additives in order to increase its physical and chemical properties. Bituminous coating waterproofing is mainly of 4 types, such as solvent based, water based, polymer modified, and rubberized bitumen coatings. The minimum thickness of the bituminous coating is 1mm and it can varied with the purpose. Bituminous coating waterproofing should be applied between +5°C to +35°C. 

The bituminous coating waterproofing layer is not breathable, not UV resistant, and less chemically resistant. This coating can withstand more than 10 years and it can be applied to below grade such as foundations, retaining walls, basements, roofs, metals, bridges, decks, and tunnels. When the waterproof bituminous coating is exposed to UV light, high temperature, cold temperature, high humidity, and higher water pressure can damage the membrane over time. In order to maintain the bituminous coating, waterproofing you should maintain and repair it properly and on time.

What is Bituminous Coating Waterproofing?

Bituminous coating waterproofing is a protective layer applied to surfaces to prevent water ingress. It consists of bitumen, a petroleum-derived hydrocarbon. It is modified with polymers or fillers for enhanced performance. Due to the liquid form, it is easy to apply on the uneven surface. Bituminous coating waterproofing is a seamless barrier and it can withstand in mid-range of water pressure, UV lights, and chemicals.

What are the 4 types of Waterproof Bitumen Coating?

These are the most used 4 types of bitumen coating waterproofing.

1. Solvent based bitumen coating: Solvent based bitumen coatings are quick-drying and highly adhesive, hence they are commonly used for concrete, metal, and wooden surfaces.
2. Water based bitumen emulsion:  Water base bitumen (Bitumen emulsion) is an eco-friendly, low-odor, waterproofing membrane. It can be used for damp-proofing foundations and walls.
3. Polymer modified bitumen coating (PBMC): Polymer modified bitumen are made by enhancing the SBS or APP for superior flexibility, crack resistance, and durability. 
4. Rubberized bitumen coating: Rubberized bitumen coating is reinforced with synthetic rubber for high elasticity and self-healing properties, great for areas subject to movement.

Before you choose a waterproofing membrane among these 4 types, we highly recommend to check this guide 10 Types of Waterproofing Membranes: Properties, Applications, Pros, and Cons. It include all in detail about waterproofing membranes.

What is the Thickness of the Waterproof Bitumen Coating?

The thickness of bituminous waterproofing varies based on application type and exposure conditions. When you apply bituminous coating, you should maintain the thickness as below.

1. Minimum thickness: 1 mm (for light waterproofing, like interior damp-proofing).
2. Standard thickness: 2-3 mm (for basements, foundations, and walls).
3. Heavy-duty thickness: 4-6 mm (for roofs, exposed areas, and high water-pressure applications).

Multiple coats are recommended to achieve the required thickness. At Aqviz, we ensure proper layer buildup with at least two coats, allowing full drying between applications.

If you need a uniform thickness over the surface we can suggest you to use Bituminous sheet Waterproofing Membrane. It has a uniform thickness and can be appleid more effectively.

What is the Recommended Temperature for Bituminous Coating Waterproofing?

When you apply a bituminous coating waterproofing layer, you should maintain +5°C to +35°C  for gain optimum advantages.

1. Minimum application temperature: +5°C (below this, adhesion and curing slow down).
2. Optimum range: +10°C to +35°C (ensures proper adhesion, drying, and bonding to substrates).
3. Maximum exposure temperature: 85°C (for APP-modified bitumen, ensuring heat stability).

At Aqviz, we avoid application in extreme cold or wet conditions and recommend dry, mild weather for best performance.

Is Bituminous Coating Breathable?

No, the bituminous coating is not breathable. It forms a dense, impermeable barrier that prevents water and moisture from passing through. Unlike breathable coatings such as silane-siloxane or cementitious waterproofing, bituminous coatings completely seal surfaces, making them ideal for below-grade waterproofing, basements, and foundations where moisture ingress needs to be entirely blocked. 

However, non-breathability can sometimes trap moisture if applied to damp surfaces, leading to potential blistering. At Aqviz, we always ensure proper substrate preparation and drying before applying bitumen coatings to avoid trapped moisture issues.

Is Bituminous Coating UV Resistant?

No, Basic bituminous coatings are not UV resistant and degrade when exposed to prolonged sunlight. When bitumen coating is continuous exposure to UV it can brittle, crack, and lose its waterproofing properties over time. So Aqviz we highly recommend you to use a protective topcoat (e.g., acrylic, polyurethane, or reflective aluminum coating) to extend the lifespan of the bitumen layer.

Is Bituminous Coating Chemical Resistant?

Yes, bituminous coatings have good chemical resistance against sulfates, chlorides, mild acids, and alkalis. Hence it is suitable for waterproofing in industrial and sewage treatment plants. But they are not resistant to strong solvents, hydrocarbons, or petroleum-based chemicals. These can break down the bitumen.

At Aqviz, we recommend epoxy-modified bitumen for areas exposed to harsh chemicals, as it enhances durability and resistance to aggressive substances.

How Long Can Bituminous Coating Waterproofing Last?

Bituminous coating waterproofing can last 20-30 years when it is installed on foundations and basements. When this is installed on roofs, terraces, and retaining walls it can withstand 10-15 years. It can withstand 7-12 years when it is installed in highly stressed environments such as industrial zones. 

In order to withstand the bituminous coating waterproofing layer, it should be maintained and protected properly.

How to Seal Edges in Bituminous Coating Waterproofing?

When using bituminous coating waterproofing corners and edges should be sealed properly. In this step, you can embed polyester fabric or fiberglass mesh between coats to prevent cracking, as well as you can use two coats, use a polymer-modified bitumen mastic, and apply an aluminum based or polyurethane protective layer for the top coat.

Where to Apply Bituminous Coating Waterproofing?

The bituminous coating can be used in various waterproofing applications such as,

• Below grade waterproofing: Foundations, retaining walls, basements, and underground structures to prevent moisture ingress.
• Roof waterproofing: Flat and sloped roofs (need a protective topcoat for UV resistance).
• Wet areas: Bathrooms, kitchens, and water tanks to prevent water penetration.
• Metal protection: Coating for steel pipes, metal structures, and storage tanks to prevent corrosion.
• Bridge decks & tunnels: Heavy-duty applications where water resistance and flexibility are critical.

Environmental Factors That Impact Bituminous Coating Waterproofing

Bituminous coating waterproofing is a highly effective water barrier. But several environments can influence its performance and longevity.

• High temperatures (>35°C) can soften bitumen, causing it to sag or become tacky.
• Cold temperatures (<5°C) can make it brittle, reducing flexibility and adhesion.
• Prolonged exposure to direct sunlight degrades bitumen, causing it to crack and lose elasticity.
• High humidity can slow down curing, while trapped moisture can cause blistering and adhesion failure.
• Bituminous coatings resist mild acids and alkalis but degrade when exposed to petroleum-based solvents and harsh chemicals.
• In underground applications, continuous water pressure can lead to failure if the coating is not thick enough.

What are the Pros and Cons of Bituminous Coating Waterproofing?

These are the pros and cons of bituminous coating waterproofing.

Pros of bituminous coating waterproofing

• Highly Waterproof: Bituminous coating waterproofing creates an impermeable barrier against water and moisture.
• Flexible & Crack Resistant: Bituminous coating waterproofing adapts to minor structural movements.
• Good Adhesion: Bituminous coating waterproofing bonds well to concrete, metal, and masonry surfaces.
• Cost Effective: Bituminous coating waterproofing is more affordable than many other waterproofing solutions.
• Wide Application Range: Bituminous coating waterproofing is used for basements, roofs, metal protection, and industrial waterproofing.
• Can Be Reinforced: Bituminous coating waterproofing works well with fiberglass mesh or polyester fabric for extra strength.

Cons of bituminous coating waterproofing

• Not UV-Resistant: Bituminous coating waterproofing requires a topcoat (e.g., aluminum or acrylic paint) for exposed areas.
• Not Breathable:  Bituminous coating waterproofing traps moisture if applied to damp surfaces, leading to blistering.
• Limited Chemical Resistance: Some types degrade when exposed to solvents and petroleum-based chemicals.
• Messy Application: Can be sticky and difficult to clean if spilled.
• Long Curing Time: Bituminous coating waterproofing takes 24-48 hours to fully dry, depending on weather conditions.
• Temperature Sensitivity: Bituminous coating waterproofing becomes brittle in cold temperatures and softens in high heat.