Key Takeaways:
- Definition: Basement tanking involves applying a waterproof membrane or coating to the interior or exterior surfaces of a basement to prevent water ingress.
- Materials Used: Common materials include cementitious slurries, bitumen-based coatings, and synthetic membranes.
- Types of Waterproofing: Tanking is classified as ‘Type A’ waterproofing, focusing on creating a barrier against water.
- Limitations: While effective, tanking systems can be susceptible to damage over time, potentially compromising their waterproofing capabilities.
- Alternative Methods: Other waterproofing methods, such as cavity drainage systems (Type C), manage water ingress differently by directing water away from the structure.
Basement tanking is a method of protecting basements and any other below-ground structures against water penetration and seepage. In the UK, because of frequent rainfall and high water tables that can dampen basements and floods, tanking makes basements dry.
For any extended period of building or a new building being constructed below the ground floor, basement tanking is a vital process to prevent water seepage and, ultimately, to create usable space below the ground.
How Does Basement Tanking Work?
In interior or exterior walls and floor of a basement, the process of constructing a waterproof barrier is known as ‘tanking’. It helps avoid leaking water to the inside walls of the construction, thus avoiding wetting of walls.
Internal Tanking
Internal tanking is erecting a waterproof membrane or slurry on the wall and floor of the basement. This method is preferable in retrofit projects where there is likely to be limited access to the outside environment.
External Tanking
External tanking involves putting a barrier on the outer walls before they are filled with soil. It is common when constructing from scratch, with the intention of not allowing water to touch the structure.
Combination Systems
Occasionally, tanking is also done in conjunction with other types of waterproofing, such as cavity drainage membranes.
Why is Basement Tanking Important in the UK?
The level of rainfall is often high, while the fluctuating water table also means that waterproofing is crucial when designing below-ground areas in the UK. Without proper tanking, basements are prone to issues such as:
Damp: Condensation and subsequent formation of mould is a health risk and poses a major threat to the fabric and finishes of building structures and fittings.
Flooding: Rainwater can prove devastating to any property and its contents or occupant’s possessions.
Structural Issues: Repeated flood exposure in the building causes the building’s foundation to wear down; hence, there will be cracks and possible collapse.
Types of Basement Tanking
Cementitious Tanking
This is the most preferred method when it comes to internal tanking. It entails spreading the cement-based slurry on the walls and the floor, which has been specifically developed.
Advantages:
- Cost-effective.
- Easy to apply.
- Ranging from small cars, trucks, vans, boats that are on the water, RVs, and motorcycles with sidecars.
Disadvantages:
- It may be necessitated to repeat its use from time to time.
- Slight resistance when applied to structures undergoing structural shifts.
Liquid Waterproof Membranes
These membranes are supposed to be in a liquid form, but once they are in contact with the surface, they form a waterproof surface once cured.
Advantages
- Flexible and durable.
- Applicable to irregular surfaces.
Disadvantages:
- It should be applied on a well-prepared surface.
- It may prove more costly than cementitious methods
Sheet Membranes
Sheet membrane basement tanking is a method of waterproofing that uses pre-formed sheets or rolls of waterproof material to create a barrier that prevents water ingress into a basement. This method is particularly effective in areas with high water pressure or significant risk of dampness.
Advantages:
- High durability.
- It is dependable if installed properly.
Disadvantages:
- Requires expert installation.
- There is always the possibility of failure at the poorly sealed joints.
Cavity Drain Membranes
These systems employ a studded plastic membrane, which directs the water into a drainage system and does not attempt to prevent the formation of the stain at all.
Advantages:
- Suitable for the condition under high water table status.
- Easy to repair and maintain.
Disadvantages:
- Can only be used with an additional drain system.
- It is more expensive than the conventional practices of tanking.
Key Considerations for Basement Tanking
1. Water Table Levels
Any kind of tanking project that one wants to embark on needs to consider the level of ground water table in his or her region. High water tables demand more effective ways, such as cavity drain systems.
2. Structural Integrity
All the cracks and other defects should be properly sealed before engaging in tanking in order to get the best seal.
3. Ventilation
To limit moisture growth, inadequate circulation systems can lead to condensation on the wall and should be prevented.
4. Professional Installation
Basement tanking is a technical job that needs professionals in that field. This is important because hiring a professional does the work right, and this avoids future costly mistakes.
Benefits of Basement Tanking
Increased Usable Space
The function of tanking is to create a usable space of damp and useless basements and a perfect additional bedrooms, home offices, or recreational facilities.
Property Value Enhancement
An effective waterproofing of the basement increases the space’s value, as the potential buyer is interested in a dry space.
Avoid Damp Problems
As the name suggests, tanking prevents water from penetrating into the structure and can prevent the formation of mould, mildew and structural compromise while preserving the health and the value of your property.
4. Longevity of the Structure
Well-tanked basements also reduce the chances of suffering from water-caused structural issues, hence expanding the lifecycle of your building.
Basement Tanking Costs in the UK
The cost of basement tanking in the UK varies depending on the size and condition of the basement, the method of tanking, and the materials used. Here’s a breakdown of typical costs:
- Cementitious Tanking (Type A Waterproofing): This is a common and cost-effective method involving a waterproof cement coating. Costs typically range from £40 to £60 per square meter. It’s best suited for areas with minimal water ingress.
- Membrane Tanking (Type C Waterproofing): This uses a waterproof membrane to manage water ingress and is often paired with drainage systems like sump pumps. Costs range from £50 to £80 per square meter, making it more expensive but effective for heavy water conditions.
- Liquid-Applied Tanking: Involves a seamless liquid waterproof coating that is suitable for uneven surfaces. Costs are usually £60 to £100 per square meter.
For entire projects, including materials, labour, and drainage solutions, the total cost could range from £1,000 to £5,000 for basic jobs, with larger or more complex projects going up to £10,000 to £20,000 or more. Additional expenses may include preparatory work, repairs, and drainage installations.
It’s essential to get detailed quotes tailored to your specific requirements and ensure that the work complies with British standards. High-quality installations often come with guarantees lasting 10 years or more.
Common Challenges in Basement Tanking
Incorrect Application:
If improperly used, tanking systems commonly deteriorate and allow water in, which then requires the use of significant funds for repairs.
Structural Movement:
Mobile structures will exert pressure and stress on rigid tanking systems and can lead to crack formation.
Condensation Issues:
As mentioned earlier, poor airing usually results in the formation of water, which may easily be considered as penetration.
Regulations and Standards
In the UK, basement tanking projects must comply with:
BS 8102: The British Standard for protecting below-ground structures against water from the ground. This standard provides guidelines on how to construct and install waterproofing systems.
Building Regulations: In the case of big projects, tanking needs to adhere to particular building codes that govern the construction projects. If consulting a professional, then one is assured of compliance.
Choosing the Right Professional
When selecting a contractor for your basement tanking project, consider the following:
Experience: It is essential to look for the best service providers that have done many jobs in basement waterproofing services.
Certifications: It must be done by professional companies affiliated to organizations like the Property Care Association (PCA).
Guarantees: Select a contractor who will warrant his services so that in the case of any merits being judged off, the contractor can fix them for free.
Basement tanking is an essential step in ensuring that the below-ground areas are sealed off from water penetration, especially in the United Kingdom.
With the correct method and a professional at your disposal, your basement can be converted to a dry surface, which makes it a helpful part of the house that can add value to the home.
Nonetheless, the initial costs are high, but the subsequent advantages of property protection and additional living areas make basement tanking valuable.
Frequently Asked Questions
What is basement tanking?
Basement tanking is the process of applying a waterproof barrier to the walls and floors of a basement to prevent water from entering.
Why is basement tanking necessary?
It’s essential for creating dry, habitable spaces in basements, especially in areas prone to high water tables or poor drainage.
What materials are used in basement tanking?
Materials include cementitious slurries, bitumen-based coatings, and synthetic membranes, each offering different levels of protection.
Can basement tanking be done DIY?
While some homeowners attempt DIY tanking, it’s recommended to consult professionals to ensure proper application and effectiveness.
How long does a tanking system last?
The longevity of a tanking system varies based on materials used and environmental conditions but typically ranges from several years to over a decade.
