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Structural Waterproofing Renders

A ‘structural’ waterproof render is applied to either concrete or brickwork substrates which is designed as a ‘barrier’ method of preventing water ingress into the structure. It is often referred to as ‘tanking’.

BS8102:2022 defines three main types of structural waterproofing protection for below-ground structures: Type A (Barrier Protection), Type B (Structurally Integral Protection), and Type C (Cavity Drainage).

  • Type A ‘Barrier’ protection can consist of cementitious, liquid or sheet-applied membrane barriers that will prevent water ingress in to a structure from external sources.
  • Type B ‘Structurally Integral Protection’ generally comprises the use of structurally integral watertight concrete for protection against water ingress. This is predominantly found in NEW construction.
  • Type C ‘Cavity Drainage’ differs from both barrier and structurally integral protection by ‘managing’ water ingress rather preventing it. In other words, it is a drained protection system.


BS 8102:2022 – the LATEST version of the standard – defines four grades of waterproofing protection for below-ground structures: 1a, 1b, 2, and 3. These grades determine the level of water-tightness required for a specific performance definition.

Here’s a breakdown of each grade:

Grade 1a Seepage and dampness from internal and external sources are tolerable, as long as it doesn’t impact the intended use of the structure.

Grade 1b No seepage is allowed, but damp patches from internal and external sources are tolerable.

Grade 2 No seepage or dampness from external sources is acceptable, but internal moisture and condensation may require management.

Grade 3 No water ingress or damp areas are tolerable. Ventilation, dehumidification, or air conditioning may be necessary to manage internal moisture.

Hand & Spray-Applied Waterproofing Renders

These renders are what are used for Type A water resistance. A waterproof render comprises a cementitious layer or layers that is applied directly to previously prepared walls, floors and soffits within the INTERIOR of a building which is either partially above or completely below ground.

Traditionally these systems are hand-applied though recent developments using low cement content alternatives have been designed and developed specifically to enable machine-sprayed applications.

These systems can be used in basements in high water table areas and can help achieve the required grades according to BS8102:2022



Waterproofing Regulations
BS8102:2022

To re-cap, the four grades of waterproofing defined under this standard are:

  • Grade 1a – Seepage and dampness from internal and external sources are tolerable, as long as it doesn’t impact the intended use of the structure.
  • Grade 1b – No seepage is allowed, but damp patches from internal and external sources are tolerable.
  • Grade 2 – No seepage or dampness from external sources is acceptable, but internal moisture and condensation may require management.
  • Grade 3 – No water ingress or damp areas are tolerable. Ventilation, dehumidification, or air conditioning may be necessary to manage internal moisture.

Waterproof Render Installation

Waterproof renders are frequently referred to as ‘structural’ as they need to be able to withstand a head of water pressure.


Such systems are normally applied in THREE waterproofing layers:

  • 1st  coat  is the ‘bonding’ layer, applied directly on to either previously prepared brickwork, blockwork, stone or concrete
  • 2nd coat is applied over the top of the bonding layer – often referred to as a ‘spritz’ coat – which is left with an open texture
  • 3rd  is the final layer which is applied as a closed-textured float finish.

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Why choose Gunite Waterproofing for Waterproof Render Installation?

Gunite Waterproofing have been keeping water out of buildings  for more than 30 years. We are accredited installers of waterproofing systems from the UK’s leading construction waterproofing materials manufacturers. These include Sika, Delta Membranes, Koster, RIW, Newton Waterproofing Systems, Wykamol and Mapei.

All our operatives undergo regular training and development to ensure that they remain accredited installers to the latest waterproofing industry standards.

Third-Party Accreditations

Whether re-waterproofing an existing structure OR making a new one waterproof, you need to be able to find an experienced partner who you can trust to deliver your requirements to the right design. All of our clients benefit from our 30+ years of knowledge & experience in delivering innovative, bespoke and cost-effective waterproofing solutions complemented by exemplary customer service.