Timberwsie workmen in a basement preparing for damp proofing

Can I Have Basement Waterproofing Installed in Older Buildings?

21 November 2023

Owning a property can bring with it a whole host of different problems that you, as the owner, will have to face and mitigate on a daily basis. One of the most common problems that properties with a below ground space can face is consistent leaks or flooding.

This can be true in properties of all types, but it’s often the case that older properties suffer more, as they might not have been constructed with modern waterproofing elements.

So, if this is the case what can be done, and can older properties be fitted with modern waterproofing designs?

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Why Might My Older Properties Basement Flood?

A flooded industrial basement


Below-ground waterproofing is a tricky and thorough process. Even now, ensuring a basement is properly waterproofed is a comprehensive procedure, with the waterproofing specialists having to adhere to the guidelines set down in BS8102:2022.

So, when we talk about properties constructed in the past, even from as early as around 1980, we are talking about properties that may not have had access to the same basement waterproofing materials, processes, or guidelines.

So, let’s think about a property built in the 19th century. A standard basement under a property this age won’t have any modern waterproofing elements ready built into its constructive elements (for example, the bricks), and it would be safe to say that any exterior or interior rendering (or ‘tanking’, as it might be known), might not have held up against the test of time.

Even if it had, one of the primary drawbacks of tanking a basement wall is that the source of the water ingress isn’t dealt with – instead, the pressure of the water builds up against the basement’s walls, and can slowly cause a fault or crack to appear, leading to even more leaks and flooding if not properly treated.

What we are trying to say is that there are plenty of reasons why older properties could be suffering from basement flooding or leaks, but that this doesn’t mean you are out of options when it comes to modernising and protecting your below ground space.

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How are New Build Properties Basement’s Made Waterproof?

Preparing for external waterproofing on new build



There are a few different methods when it comes to basement waterproofing, and by that, we mean accepted and approved methods recognised by British Standards (BS8102: 2022).

Essentially, in order to comply with modern waterproofing standards, a basement or cellar must combine two of the following waterproofing systems in order to be compliant, and considered ‘waterproofed’ according to British Standard definitions.

Type A waterproofing is the application of a waterproof slurry to the basement or cellar’s walls, either internally or externally. You might know this as tanking.

Type B waterproofing involves the property itself being constructed out of waterproof materials.

Type C waterproofing is the application of a cavity drainage system. This involves a waterproof membrane being affixed to the basements walls, which collects the leaking water and directs it via perimeter drainage channels into a sump pump, which collects and then safely pumps away the collected floodwater.

These are the recognised methods of waterproofing in Britain today, and you won’t be surprised to learn that the most common method of making new build properties compliant with BS8102:2022 is to combine Type A and Type B waterproofing during the initial construction of the property.

So, a new build house featuring a basement would have its below ground level constructed out of waterproof materials, and then whilst the basement is exposed, it would be covered in a waterproof slurry, bringing the construction in line with modern waterproofing standards quickly.

This does not apply to older properties though, so how can an older property, already built and unable to have its basement exposed via excavation, be made waterproof?

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How Can I Waterproof a Basement in an Older Property?

Technicians carrying out tanking works


Yes. To have an older property’s basement waterproofed, we commonly recommend that we first apply a Type A Waterproofing slurry to the basement’s internal walls. First, we will ask that the basement is emptied, and that the walls are either left bare, or are accessible, so that the slurry can be applied directly to the wall itself.

Once the slurry has been coated on and left to dry, the process of installing a Type C Waterproofing system can begin. Our team will work to the plans created by our waterproofing design specialists, applying the cavity membranes to your basement walls, connecting them to perimeter drainage channels, and installing a sump pump in the basement itself, so that all of the collected water can safely get pumped away from the property.

Once the cavity drainage system is in place plasterboard can be affixed over the top so that the basement can be decorated, and flooring can be put down as well – making the below ground space dry, habitable, and safe to use for all kinds of purposes.

To keep the basement protected we also recommend that you have regular sump pump servicing carried out by The Basement Sump & Pump Company, our sister company, who are capable of keeping your sump pump in good health and ready to handle heavy rainfall when it falls.

Of course, this is the case in the vast majority of situations, but there are times when older properties may need special attention – for example, when the property is listed.

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Can I Waterproof a Basement in a Listed Building?

Listed buildings often pose a problem when it comes to property care, as the changes and amendments needed to solve many different problems can be considered invasive, and potentially not in keeping with the property itself.

However, at Timberwise we have experience in waterproofing the basements of listed properties across the UK, coming up with non invasive comprehensive solutions that keep the basement of the property in question protected without changing the original character of the property itself.

This can be a tricky process, but luckily our team are highly qualified and well experienced, and are all ready to help you with whatever basement waterproofing requirements you might have. Just call 0800 288 8660, or get in touch via the online form below, and we will talk to you about how we can best protect your basement.