What Is Wall Tanking? The Ultimate Guide to Waterproofing Your Walls
Wall tanking or “tanking” is a method of preventing water ingress by creating a completely impermeable waterproof barrier on an internal wall....
Wall tanking is a specialised waterproofing process applied to the internal surfaces of a basement or underground structure to prevent groundwater and soil moisture from penetrating the walls. Unlike surface coatings that sit on top of the substrate, this method often involves installing a bonded or drained membrane system that manages water ingress and protects the internal environment.
Understanding the Mechanics of Wall Tanking
The core principle of wall tanking revolves around creating a continuous, waterproof barrier between the damp earth and the interior living space. This barrier is designed to resist hydrostatic pressure, which is the force exerted by groundwater pushing against the foundation walls. When implemented correctly, the system channels any incidental moisture towards designated drainage points, preventing it from seeping through porous concrete or masonry.
Types of Tanking Systems: Cementitious vs. Membrane
There are generally two primary categories of tanking materials used for walls. Cementitious tanking involves applying a cement-based slurry that cures to form a rigid, monolithic layer, ideal for situations where minor substrate movement is expected. Alternatively, polymer-modified membranes offer more flexibility, accommodating slight shifts in the structure without compromising the seal, which is often a superior choice for dynamic soil conditions.
The Application Process and Best Practices
Professional wall tanking is not a simple brush-on solution; it requires meticulous surface preparation. The substrate must be structurally sound, free of dust, oil, and loose particles, and any defects like cracks or voids need to be repaired with a suitable filler. Adhesion is key, and the surface is often dampened before the first coat is applied to ensure a strong bond.
- Assessment of the existing wall substrate for structural integrity.
- Crack sealing and repair of any defects to create a smooth base.
- Application of a primer to enhance adhesion between the wall and the tanking layer.
- Layering the tanking membrane with careful attention to overlaps and corners.
- Ensuring termination at a secure point, often into a wall slab or vertical cut-off.
Drainage Integration: The Final Layer of Defence
Modern waterproofing standards, such as those outlined in British Standards BS 8102, emphasise that tanking should be integrated with a cavity drain membrane system. This approach involves a physical gap between the tanked wall and the earth, allowing water that enters the structure to be collected and diverted to a sump pump or drain. This mitigates the pressure on the tanked surface and provides a secondary line of defence.
Addressing Sulphate Attack and Chemical Exposure
In specific environments, such as areas with high clay content or former mining sites, the ground may contain sulphates that can attack standard cementitious materials. In these instances, a specialised tanking system resistant to chemical and sulphate attack is necessary. Selecting the correct product for the specific soil chemistry is critical to the long-term success of the project.
Common Misconceptions and Limitations
It is important to understand that no tanking system is entirely immune to failure if subjected to extreme pressure or poor installation. The term "tanking" does not imply that the wall is indestructible; rather, it means the system is designed to manage water effectively. Furthermore, ventilation is still required to prevent condensation on cold interior surfaces, which tanking does not address.
For optimal results, wall tanking should always be specified and installed by experienced professionals who understand the interplay between waterproofing, drainage, and substrate preparation. When done right, it transforms a vulnerable basement into a dry, usable space that is protected from the damaging forces of groundwater.
<strong>The Complete Guide to Wall Tanking & Waterproofing - Permagard</strong><p>Wall tanking or “tanking” is a method of preventing water ingress by creating a completely impermeable waterproof barrier on an internal wall.</p>
<strong>Waterproofing and damproofing walls with DIY Tanking - YouTube</strong><p>21.09.2015 ... What is tanking? Tanking is waterproofing walls. They might be cellar walls or basement walls or even retaining walls. Tanking is applying a ...</p>
<strong>How to tank walls - Restoration UK</strong><p>Tanking isn't just used in cases of rising damp. If you're converting a basement or have an area of your home that's below the level of your damp proof course, ...</p>
<strong>What Does Tanking Do? Whilst damp proofing, tanking provides a ...</strong><p>14.06.2025 ... Whilst damp proofing, tanking provides a protective barrier between the brick work and new plaster . It's a vital part of the process as if ...</p>
<strong>Tanking & Waterproofing - What's The Difference?</strong><p>Basement tanking, cellar tanking or wall tanking describes the application of one type of coating or membrane (barrier protection). We provide products for ...</p>
<strong>A complete guide to tanking a wall - Build and Plumb | Ideas & Advice</strong><p>It's a specially designed thick liquid made from cement, aggregates and chemical modifiers that creates a waterproof coating on masonry. Tanking slurry works by ...</p>
<strong>Tanking? : r/DIYUK - Reddit</strong><p>06.01.2024 ... To remove localised areas of dampened plaster from first floor landing walls. Apply salt neutraliser and render with a waterproof based ...</p>
<strong>Basement & Cellar Tanking | Expert Advice & Solutions - Peter Cox</strong><p>Tanking a cellar or basement can protect walls and floors from moisture, creating a dry environment. Expert advice on tanking and Type A waterproofing.</p>
<strong>damp (dare I say "waterproof tanking".....) - Period Property UK</strong><p>26.10.2023 ... Otherwise the current approach is to fit a drainage system. This effectively involves having a false inner wall with a waterproof membrane so ...</p>
<strong>Tanking - Designing Buildings Wiki</strong><p>05.10.2020 ... Tanking is a term used for creating a tank-like seal to protect walls against water penetration. The Building Regulations stipulate that tanking must be ...</p>
<strong>Preparing And Tanking A Brick Wall - YouTube</strong><p>14.06.2022 ... Preparing And Tanking A Brick Wall Tanking Slurry. ... This content isn't available. Preparing And Tanking A Brick Wall Tanking Slurry ...</p>
<strong>Your thoughts on tanking? | Screwfix Community Forum</strong><p>31.07.2018 ... But with walls which are above ground and shared by homes, all tanking does it to keep that tanked wall thoroughly damp in its core. So, if ...</p>
<strong>Tanking - what is it and when to apply</strong><p>22.03.2009 ... Tanking is, as its name suggest a method of sealing a wall to prevent water ingress (think 'water tank) often mis-specified as a cure for ...</p>
<strong>How To Waterproof a Wall With Tanking Slurry: DIY Guide - YouTube</strong><p>18.08.2025 ... In this video I show how to tank a wall using waterproofing slurry to stop penetrating damp and moisture coming through masonry. KA Tanking ...</p>
<strong>Damp-Proof Tanking: What Is It, How Does It Work, and Do You ...</strong><p>06.06.2023 ... It involves waterproofing walls with a tanking slurry or membrane sheets, depending on what works for you. Tanking creates a water-repellent ...</p>
<strong>What Is External Wall Tanking? - Permagard</strong><p>External tanking is the process of sealing the outside of a building or substructure to protect it from water ingress, flooding and other water damage.</p>
<strong>What is "Tanking" - YouTube</strong><p>05.05.2020 ... Tanking systems above ground · KA tanking slurry application pt1 · Xypex - How to Waterproof Concrete Block Walls (CMU) · Failed basement ...</p>
<strong>Tanking paint for damp penetration on internal walls? - Reddit</strong><p>05.11.2021 ... Tanking paint will stop the damp penetrating but this is simply masking the symptons. Water in ingressing from somewhere and needs to be fixed.</p>
<strong>Tanking Membrane | Waterproof Wall Membrane - Restoration UK</strong><p>Tanking Membrane waterproofs the inside and outside of damp buildings, more often than not supplied as a waterproofing cavity membrane.</p>
<strong>Tanking to Prevent a Damp Course Breach – Light Refurb in Stoke ...</strong><p>29.09.2020 ... What is tanking? How does tanking stop damp? What is a damp course breach? In this video, John explains how to use tanking slurry (a liquid ...</p>
