How to Apply Bituminous Waterproofing on a Foundation?
Installing bituminous waterproofing on the foundation is highly recommended to prevent water infiltration to the inside. When you install bituminous waterproofing on the foundation, you should follow the below 8 steps. It includes all the details from start to finish with additional information.
As waterproofing experts, we always follow the below steps and we have conducted so many waterproofing projects in the last few years. You had better ask any questions regarding these steps.
8 Steps to Apply Bituminous Waterproofing on the Foundation
These are the 8 steps for foundation waterproofing using bitumen membranes.
- Inspect the foundation for waterproofing
- Choose the right bituminous waterproofing membrane
- Prepare the foundation surface
- Apply primer on the surface
- Apply bituminous coating on the surface
- Install bituminous membrane and seal the joints
- Allow the bituminous waterproofing to dry
- Protect the waterproofing layer
1. Inspect the Foundation
Before applying bituminous waterproofing on the foundation, Aqviz, we thoroughly inspect foundation cracks, spalling, moisture stains, or efflorescences that indicate water infiltration from the surface. You should pay special attention to foundation joints, corners, and areas near drainage systems, as these are common weak points. Aqviz highly recommends you to mark these areas specially for later foundation checkings.
2. Choose the Right Bituminous Waterproofing Membrane
Bituminous waterproofing membranes are mainly 2 types: bituminous coatings (liquid-applied) and bituminous membranes (sheet-based). For minor foundation surface protection, a liquid coating works well, while severe foundation moisture issues require a torch-applied or self-adhesive membrane. When you choose this you should consider factors like foundation exposure, water pressure, and surface condition to select the best solution for long-term protection.
3. Prepare the Foundation Surface
A clean, dry, and smooth foundation surface is key to effective waterproofing. So we recommend you to start by removing dirt, loose debris, and oil stains using a wire brush or pressure washer. Then you should fill any cracks or holes, and must be patched with a suitable mortar or sealant. For rough surfaces, we recommend applying a leveling coat to ensure proper adhesion of the waterproofing layers to the foundation.
4. Apply Primer on the Foundation Surface
Priming is essential as it enhances adhesion between the foundation and the waterproofing material. We use a bitumen-based primer and apply it evenly with a roller or brush. The primer should cover the entire foundation surface and dry completely before applying the waterproofing membrane. It will take 2–4 hours but it depends on weather conditions.
5. Apply Bituminous Coating on the Foundation
Once primed, our experts apply the bituminous coating in multiple layers using a brush, roller, or spray on the foundation surface. Each coat must be spread evenly, ensuring full coverage without gaps.
We have included everything about foundation waterproofing in the guide. How to waterproof a Foundation? It has all steps from stat to finish about foundation waterproofing.
6. Install Bituminous Membrane and Seal Joints
For added protection, we install a bituminous membrane, either self-adhesive or torch-applied on the foundation. Sheets must be overlapped by at least 4 inches to prevent leaks. Special attention is given to sealing joints and edges with a blowtorch or adhesive to ensure a watertight bond. Proper sealing prevents water from seeping into foundation cracks over time.
7. Allow for Drying
After applying the bituminous coating and membrane, we keep it for drying. Liquid bituminous coatings typically require 24 to 48 hours to cure fully, depending on temperature and humidity. When we use a membrane, we keep it until bonds securely before any backfilling.
8. Protect and Backfill the Foundation
To prevent damage during backfilling, we install a protection board or drainage mat over the waterproofed foundation surface. This shields the membrane from sharp rocks and pressure during soil compaction. When backfilling, we use granular or well-draining soil and compact it gently in layers. As well as Aqvize we build proper drainage around the foundation every time. It ensures long-term waterproofing performance with minimum cost.
What are the Optional Waterproofing Membranes for Foundations?
Optional waterproofing membranes for foundations we use these 5
- Cementitious waterproofing: Highly recommended for minor foundational movements
- Polyurethane liquid waterproofing: Excellent for foundations that are prone to cracks
- Bentonite clay membrane: Aqviz uses bentonite for deep foundation waterproofing
- PVC and EPDM waterproofing: Commonly used for higher chemical resistant foundations
- Crystalline waterproofing: Use to minimize the moisture impact foundation waterproofings
Is Bituminous Waterproofing Suitable for all types of Foundations?
No, bituminous waterproofing is not suitable for all types of foundations. It works best for concrete and masonry foundations exposed to high moisture but may not be ideal for foundations with excessive movement or extreme chemical exposure. For highly flexible structures or areas with aggressive groundwater, you can use polyurethane, bentonite, or PVC membranes.
Read more about: How to Waterproof Concrete Foundation?
What are the Common Problems with Bituminous Waterproofing, and How Can They Be Fixed?
These are the common 5 problems and suitable solutions for bituminous waterproofing on the foundation
- Poor adhesion: Ensure the foundation is clean, dry, and primed before application.
- Cracking or brittleness of the structure: Use a modified bitumen mix with elastomers for flexibility and inspect for reapplication when needed.
- Improper sealing at joints: Overlap bituminous membrane sheets by at least 4 inches and use a blowtorch or adhesive to ensure a watertight seal.
- Damage during backfilling: Install a protection board or drainage mat before the backfilling foundation and use compacted, granular soil.
- Degradation over time: Use a protective layer like cement board or drainage sheets and regularly inspect the foundation for wear.
Can Bituminous Waterproofing be Applied Over Existing Foundation Coatings?
Yes, bituminous waterproofing can be applied over existing foundation coatings. But Aqviz experts always recommend you to use the foundation waterproofing membrane on properly prepared surfaces. The old coating must be clean, dry, and free from loose material to ensure good adhesion. If the existing layer is damaged or peeling, it should be removed or repaired before applying a new bituminous layer.
Are Bituminous Waterprofing Membranes Flexible?
Yes, bituminous waterproofing membranes are flexible, but the degree of flexibility depends on the bitumen type. Modified bitumen membranes, such as SBS (Styrene-Butadiene-Styrene) and APP (Atactic Polypropylene), offer enhanced elasticity and adaptability to structural movements. As well as standard bituminous coatings (without modification) can become brittle over time, especially in extreme temperatures
Are Bituminous Waterproofing Membranes Root Resistant?
Not all bituminous membranes are root-resistant, but special root-resistant versions are available. Standard bituminous membranes can be penetrated by aggressive roots, making them unsuitable for areas near trees or green roofs
Are Bituminous Waterproofing Membranes Environmentally Friendly?
Bituminous membranes are not the most environmentally friendly option due to their petroleum-based composition. Their production and disposal can contribute to carbon emissions and waste. However, some modern formulations include recycled materials and improved sustainability measures. For more eco-friendly choices you can use bentonite clay or polyurethane-based waterproofing on the foundation.
Are Bituminous Waterproofing Membranes Durable for Foundations?
Yes, bituminous membranes are highly durable for foundations, offering long-lasting waterproofing when properly installed. They resist moisture, chemicals, and ground movement, with a lifespan of 20-30 years or more.
