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What is the Best Basement Waterproofing Method for You?

Here at Garratt’s Damp & Timber, we deal in two different methods of basement tanking known simply as Type A and Type C. To avoid any confusion, there is a Type B but that is directly related to the construction of the property and therefore, not something that we would engage in.

Water drops on a waterproof surface

When it comes to determining the best basement waterproofing method for your property, several factors have to be considered. These can be related to financial constraints, condition of the property and its geographical location. Our professional team will always be best placed to offer advice on the ideal method of tanking for your individual needs but, in this post, we will offer an insight as to what to look for in determining the most suitable solution for you.

Condition of the Walls

Due to the difference in materials and methods used as a part of each basement waterproofing method, a key factor in picking which system to install is the condition of the wall before any work is completed. The Garratt’s Damp & Timber team will always survey the property to determine its condition and diagnose any damp-related issues that the owner may or may not have been aware of.

If our team finds that the basement structure is in good condition, meaning that the walls have not been compromised by any movement, there is a good chance that Type A will be the preferred method. This is because, as the simpler of the two types of basement tanking, a relatively simple barrier installation will keep the area waterproofed. To do this, the walls are stripped back to their base material, with a sand and cement render splatter coating applied, as well as a multi-coat render mixed with a waterproofing agent.

Should, however, our team find that the walls of your basement have been compromised by high volumes of penetrating damp and/or are not determined to be in good structural condition, Type C will be recommended, which is otherwise known as a water management system or Membrane Sealed Tanking. This method of tanking is more complex, as the team will install a specialised membrane into the walls, ceiling, and floor of the basement. Plugs and sealing tapes are used to fix and seal the membrane to the wall that then diverts the water into the perimeter channel, which is installed around the base of the walls and floor. These channels then redirect the water into a sump and pump system which distributes the unwanted water away from the property.


The geographical location of the property in question is also a key consideration when deciding on which type of basement waterproofing method to opt for. Even if the basement is in good condition, with walls that display only small signs of penetration, Type C could still be recommended due to the geological details of the area. For example, clay substrate will take far longer to allow rainwater to percolate back into the watercourse than gravel.

Therefore, properties in London that are built upon clay have an increased likelihood of failure caused by the build-up of groundwater and pressure over an extended period of rainfall, putting more strain on the internal waterproofing system. If the area was gravel, and the water table was below the floor slab, the chosen waterproofing would not come under any pressure from the percolating rainwater and could, therefore, be less robust.

In these instances, even though there has not been any history of water penetration, the team may still recommend Type C basement tanking to safeguard against the increased risk of damp in the future. Without Membrane Sealed Tanking, along with the sump and pump system that distributes standing water away from the property, there is a higher risk of serious damage to the structure of the building leading to expensive repair work.

Garratt’s Damp & Timber may recommend considering Type C as your basement tanking method of choice, but no two projects are ever the same. You can call our team of damp-proofing professionals to survey your property and offer their expert advice, along with a no-obligation quotation.

According to Your Budget

There is no getting away from the fact that finances make up a huge part of the decision-making process, so it is important to be aware of the costs involved. Although it is impossible to offer a definitive price, because of the differences between projects, Type A is generally the less expensive of the two methods of waterproofing. This comes down to the labour and materials involved in installing the tanking system, which is generally quite basic compared to the more complex Type C.

This is certainly why Type A is the most common form of basement tanking that is utilised in the waterproofing repair industry. When homeowners know that their basement and walls are in good condition with no signs of damage, the preferred option for both parties is Type A due to the costs and work involved.

If your property is in a location that sees higher than average moisture levels and your budget allows for Type C, we would certainly recommend at least considering Membrane Sealed Tanking in your basement. Without the correct system in place for your property’s requirements, the costs of repair work required will almost certainly be exponentially more expensive in the long run.

Calling the Professionals

Any type of basement tanking system should be installed by a team of professionals, such as Garratt’s Damp & Timber. An incorrectly installed system is worse than having none at all, with the risk of groundwater leaking through from the dry side of the membrane potentially caused structural damage that will require repair work, as well as to the tanking system itself.

For more information on the necessities of waterproofing your basement and to seek expert advice on the best solution for you, we invite you to get in touch with our team today. If you are based in London and the Home Counties area, we can arrange to come out to inspect your property and offer a quotation, along with a clear plan of action regarding the work involved and how long it will be expected to take.

Give us a call on 0208 535 7536 or send Garratt’s Damp & Timber a message via the contact page and a member of the team will get back to you as soon as possible.

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