Our Waterproofing
Services

We offer a comprehensive range of below & above-ground waterproofing services for ALL types of structure. Whether re-using an existing basement to convert into usable new office space or living space, we offer a range of solutions that are fully compliant with BS8102:2022.

These are generally achieved through the use of structural waterproof renders, pre & post-applied membranes &/or cavity drainage systems.

At Gunite Waterproofing, we deal with resolving basement water ingress issues across London every day. With our depth of experience gained from delivering waterproofing solutions for more than 30 years, we’re very well placed to help you overcome water ingress problems to your building’s basement and to keep water out.

Continually rising water tables – Specially in areas historically affected by groundwater flooding across parts of South London and the London Basin – are a principal cause of basement water ingress. Historically, groundwater levels were artificially lowered by heavy pumping for industrial and municipal supply which no longer happens. This combined with climate change significantly affecting rainfall patterns means that groundwater recharge takes place. This causes the water table to rise with groundwater levels rising and moving much closer to basements, tunnels & a building’s foundations.

This groundwater ‘recharge’ directly affects all manner of below-ground structures, including: basements and semi-basements, lift pits, service ducts, cable trenches and older Victorian foundations which were never designed for high water tables. The typical impacts of these issues are groundwater seepage through floors and walls with the failure of previously installed water ingress (‘tanking’) measures occurring because they were only designed for lower water pressures.
The problem with groundwater recharge is it doesn’t just add to the water level, it also adds pressure. As the groundwater level rises, it increases lateral pressure on walls and floor slabs – be they brick, block or reinforced concrete – and can result in structural failure. This is because the significant increase in lateral loads are beyond what the structure’s elements were designed to withstand. Uplift pressure from underneath the floor slab increases ‘heave’ (a lifting of the floor slab) and micro cracks widen allowing an easier passage for groundwater.

This ‘lateral’ pressure if often referred to as hydrostatic pressure. If this lateral – or hydrostatic – pressure exceeds the structural capacity of walls and slabs, it can cause ‘bowing’ – where the wall(s) begin to curve or lean inward. It may also result in horizontal or diagonal cracking typically at the middle or lower part of walls indicating significant stress. In the worst cases, this can culminate in a collapse. Such increased lateral – or hydrostatic – pressure will force water through the smallest of cracks or pores in brick or concrete. The result? A flooded basement.

The only effective way to keep water out from below-ground structures is to provide a watertight ‘barrier’ externally, to stop water getting in from the outside. The downside however is that it is invariably neither cost-effective or practical to do this with existing buildings. So you therefore have to utilise waterproofing methods from the INSIDE of the existing structure. This is where Gunite Waterproofing can help you.

A basement structure can be utilised for a variety of uses and room types. Whether this is car parking, mechanical & electrical plant rooms, a gymnasium, a cinema, changing rooms, multiple bedrooms, an archive store, offices or a whole living space. But any modification or change of use will need to comply with the latest British Standard – BS8102:2022 – the key code of practice for protecting below-ground structures against water ingress.

Gunite Waterproofing can help you with the waterproofing design of your below-ground structure and guiding you through a structured design process followed up by the professional installation of the required waterproofing solution.
Failure to follow this standard & the structured design process of BS8102:2022 can culminate in water ingress where it’s absolutely not wanted. This standard matters both legally AND financially. Failure to comply is a common reason for basement flooding claims, professional negligence cases and insurance companies refusing to pay for remedial works.

One of the key principles of BS8102;2022 designers can under-appreciate is that combined protection is often required. In other words, that single systems are rarely adequate, particularly in high-risk areas such as London. At Gunite Waterproofing, we are completely independent and NOT tied to any particular manufacturer or system, so we only design systems based on what’s right for the project, NOT what’s best for the designer and/or installer.

As well as being installed by a competent and experienced basement waterproofing contractor such as Gunite Waterproofing, ‘maintainability’ of the designed system is also important. The installed solution must be able to be inspected for issues and be maintainable. Importantly also where systems that entail the use of cavity drainage, pumps, sumps and drainage must all be accessible for both maintenance and repair.

We work in London and the South-East

We work predominantly throughout London re-waterproofing basement structures and will ensure that your project has a thorough risk-based approach ensuring the outcome of a watertight basement. We work with a range of different systems which – combined with many years of basement waterproofing installation experience – will ensure that you have the best solution that will meet both your usage requirements and comply with the necessary regulatory standards.