Basement Waterproofing

May 19, 2011
Depending on the clients requirements, often in the first instance an investigative survey is required to ascertain the underlying problem.We then put together a specification and provide the client with a breakdown of recommended treatments, installations and an overall system to provide the optimal solution(s).

 The recommended solution will essentially depend on the intended use of the basement, its current condition and the surrounding environment. If the existing structure is fundamentally sound or to be built new, Aquarend may recommend a cementitious tanking system. The most prominent being the Sika 1 Pre Batched method.

Please note Aquarend are members of the Sika Registered Waterproofing Contractors scheme.

More information can be found here:

If an existing basement, be it old or new is in poor condition, a cavity drainage system which utilises an extruded plastic membrane along with a sump and pump to drain the water could be preferable.


Waterproofing new and existing basements
Cementitious tanking using renders and slurries
Cavity drainage membranes
Existing basement methods:
Cementitious tanking using renders and slurries
Cavity drainage membranes
Leak sealing by polyurethane & resin injection (mainly used for localised repairs)
Sheet membranes
As such we recommend yearly maintenance of such systems.


Cementitious Renders & Coatings


These systems utilise specialist waterproofing multi-coat renders, or a multi-coat cementitious slurries that can withstand the external water pressure often found in below ground locations.

Once installed, a cementitious render tanking system, such as the Sika 1 system, will maintain a dry environment by creating a physical barrier to water trying to enter the structure.

Cementitious coatings can be applied direct to the substrate as long as the substrate is sound.

A requirement of a rendered tanking system is the preparatory works of the substrate of ten carried out by bush hammering, grit blasting or needle gunning. This ensures all surface laitance is removed from the substrate and good key is available for the render and sealing materials to bond to.

Multicoat cementitious render applications can be installed with several interim coats and finish membranes to suit the end use of the area and or best suit the degree of water pressure resistance required.

For sealing of construction & expansion joints, cracks, fissures and between differing structures within a substrate, a Hypalon Strip bonded with an epoxy resin is used to provide maximal potential joint movement without damaging the integrity of the waterproofing system.

As a Sika Registered Contractor, we are able to offer a ten year Sika guarantee from the manufacturer along with our own ten year Aquarend guarantee.


Cavity Drainage Membrane Systems


These work on the principal of allowing ground water to continue penetrating the structure but control it through diversion to suitable drainage point(s) or sump(s) & pump(s).

Cavity membrane systems do not allow pressure to build up behind them against the internal construction and are impermeable to water, gas and water vapour, thus protecting the basement space from dampness and its associated problems. Membranes can be laid on floors and fixed to walls using special plugs and sealing materials and they can be fitted with little or no preparation to the substrate.


Once fitted, internal wall surfaces can be dry lined or plastered directly, and floors can be screeded or boarded with a suitable system.

This method of basement waterproofing allows decoration and floor finishes to be completed almost immediately, without long drying out periods.

However, these systems are a “maintained” system, meaning there are often sumps, pumps and or drainage routes which need checking regularly for debris, damage and blockages.

Click here for dedicated Cavity Membrane Page

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