Water damage is one of the most common issues faced by property owners with below-ground spaces like cellars and basements, especially in a city like London, where unpredictable weather and high water tables can make moisture ingress a real concern. If you’re dealing with a damp or leaky cellar, tanking is a tried and tested method that can prevent water from penetrating your space, keeping it dry and usable.

At BH Basements, we’ve been doing this for 35 years. Here’s all we got to say about tanking a cellar to prevent water ingress, best practices for waterproofing older buildings in London, and how basement tanking safeguards against moisture and dampness.

Tanking Techniques to Prevent Water Ingress in Cellars

Tanking a cellar involves applying a waterproof barrier to the walls and floors, creating a sealed space that prevents water from penetrating the building. This is particularly important in London, where cellars are often exposed to fluctuating water tables and frequent rainfall. These are the most common tanking techniques used to keep your cellar dry:

Internal Tanking

Internal tanking is one of the most effective techniques for preventing water ingress in cellars. This method involves applying a waterproof slurry or membrane to the inside walls and floors of the cellar, creating an impermeable barrier that prevents water from seeping through.

• Waterproof Slurry: A specially formulated slurry is applied directly to the interior surfaces of the cellar. Once cured, this coating forms a continuous, watertight layer that blocks moisture.
• Liquid Applied Membranes: Liquid waterproof membranes are another option for internal tanking. These membranes are painted or sprayed onto the walls and floors, ensuring complete coverage and an effective seal against moisture.

External Tanking

External tanking is another technique used to prevent water ingress, although it can be more challenging to implement in existing buildings. This method involves applying a waterproof membrane or coating to the exterior of the cellar walls, stopping water before it even reaches the internal structure.

• Barrier Against Groundwater: External tanking is highly effective because it prevents groundwater from making contact with the building itself. However, it typically requires excavation around the perimeter of the cellar, which may not always be practical in densely populated areas like London.

Cavity Drainage Systems

While not strictly a tanking method, cavity drainage systems are often used alongside tanking to manage water ingress effectively. In this system, drainage channels are installed to collect and direct any water that enters the space to a sump pump, which then removes it from the cellar.

• Multi-Layer Protection: Combining a cavity drainage system with internal tanking can provide a highly effective, multi-layer approach to waterproofing your cellar. This method ensures that any water that manages to get through the initial tanking layer is quickly drained away, preventing damp and water buildup.

Best Practices for Waterproofing Older Buildings in London

London is home to many older buildings, and waterproofing these structures comes with its own unique set of challenges. When tanking a cellar in an older property, it’s important to consider the building’s age, materials, and existing conditions to determine the best course of action.

1. Assessing the Condition of the Building

Before starting the process of basement tanking, it is crucial to assess the condition of the building. Older buildings often have different types of foundations and building materials that may require specific approaches to waterproofing.

• Check for structural issues, whether it be cracks, subsidence, and other structural issues can affect the effectiveness of tanking. Addressing these issues before starting the waterproofing process will help ensure that the tanking provides lasting protection.
• Identify the primary sources of moisture affecting the cellar. This could be due to a high water table, leaking pipes, or poor drainage. Understanding the source of the water ingress will help determine the best waterproofing technique to use.

2. Choosing the Right Tanking Method

Older buildings in London often require careful consideration when selecting a tanking method. In many cases, internal tanking is the preferred solution as it does not require excavation and is less invasive compared to external methods.

• Some older buildings were constructed using porous materials like brick or stone, which can be prone to moisture ingress. Choosing a tanking method that is compatible with these materials is essential to ensure long-term success.

3. Working with Specialist Contractors

For effective tanking of a cellar in an older building, it’s advisable to work with specialist contractors who have experience in waterproofing heritage properties. Proper installation is key to achieving a waterproof barrier that will stand the test of time, and professionals can help ensure that the chosen solution is executed correctly.

How Tanking Protect Against Moisture and Damp

Moisture and damp can have serious consequences for the health of your building and its occupants. Basement tanking is an effective way to safeguard against these issues, ensuring that your cellar remains dry, usable, and free from the harmful effects of water ingress.

Preventing Structural Damage

Water ingress can lead to significant structural damage over time. Moisture can weaken masonry, cause wooden beams to rot, and lead to cracks and movement in the foundation. By tanking a cellar, you create a waterproof barrier that prevents water from penetrating the walls and floors, reducing the risk of structural damage.

Tanking helps maintain the integrity of the building’s structure by preventing water from reaching vulnerable areas. This is particularly important in older buildings, where the materials may already be weakened by age.

Avoiding Health Issues

Damp environments are a breeding ground for mould and mildew, which can cause health issues for occupants, particularly those with respiratory conditions. By tanking your cellar, you can ensure that the space remains dry and healthy, reducing the risk of damp-related health problems.

A dry cellar helps improve the overall air quality in the building by reducing the presence of allergens and mould spores. This is particularly important if the cellar is used as a living space or storage area.

Protecting Your Investment

A properly tanked cellar adds value to your property by providing additional dry, usable space. Whether you use the cellar for storage, as a utility room, or even as additional living space, basement tanking ensures that it remains functional and free from water damage.

Investing in tanking a cellar can also lead to long-term cost savings by preventing the need for expensive repairs due to water damage. By safeguarding the cellar from moisture ingress, you reduce the risk of issues like dry rot, mould, and structural deterioration.

Keep Your Cellar Dry with Effective Tanking Solutions

Tanking a cellar is an essential step in preventing water damage and ensuring that your below-ground spaces remain dry, safe, and usable. Whether you’re dealing with an older building in London or looking to protect a newly constructed cellar, effective basement tanking techniques can provide the waterproofing solution you need.

From internal tanking to external barriers and cavity drainage systems, there are a variety of techniques available to protect your cellar from water ingress. For older buildings, working with experienced contractors is key to ensuring that the right methods are chosen and properly implemented.

If you’re looking for professional help with tanking a cellar in London, contact BH Basements today. Our experienced team can provide a customised waterproofing solution that meets your needs, ensuring that your cellar remains dry and protected from the challenges of London’s climate.