What a robust waterproofing strategy will include but not be limited to:

• Devised by a Waterproofing Design Specialist who has prepared the document, along with their credentials and relevant experience
• An index of documents used to create the Waterproofing Strategy document e.g. Architects drawings, Engineers Drawings, titles of any assessments and reports
• An outline description of the applied waterproofing principles and any referenced standards used to formulate the design e.g. BS 8102:2002 in the case on basements and areas deemed to be below ground, and any reference to concrete design.

• Clear and concise observations that are relevant to, and influence the waterproofing design could for instance include:
  • Scheme type e.g. residential, commercial, etc.
  • Site topography and the interaction of the structure with that topography
  • Ground conditions on site such as geology, hydrology, and hydrogeology
  • The proposed use of the space or spaces e.g. habitable space, plant rooms, lift pits, etc
  • The construction methods and type e.g. reinforced concrete retaining walls, raft foundation, underpinning, sheet piles, secant piles etc.
  • Precise statements in relation to the waterproofing strategy. For example:
  • A list of all spaces contained below ground, complete with a clear determination of the environmental grade required for each space e.g. Area A is habitable space and required Grade 3 protection and where different grades may meet each other within the construction
  • A brief statement of how that environmental grade is to be achieved for each space e.g. Space A requires combined protection, using a Type A Barrier protection and a Type B Structurally integral protection.
  • A brief statement of how the environmental grade will be maintained and/or repaired in the event of a defect e.g. Space B is a plant room, requiring an environmental grade 2. The Type B Structurally integral protection system used to provide this protection will remain accessible internally for inspection and any repairs.
  • The existing and proposed site levels and any features which may impact on the areas of building below ground level.
  • Annotated drawings in relation to the waterproofing strategy, provided by the Waterproofing Design Specialist.
  • A brief list of the selected products being used to deliver the strategy, inclusive of any supporting drawings in relation to detailing or interfaces with other elements e.g., penetrations, terminations above ground with cavity trays, etc.
  • The important area of drainage requirements that support a structural waterproofing design which takes note of the need to lower and reduce and mitigate the effects of both ground water and percolation of rainwater into the ground.

At SWS we can support your project with a waterproofing strategy that not only keeps the insurer correctly informed of the key waterproofing stages – thus avoiding costly retrospective works at a later stage in the construction phase, this also ensures that the design team and contractor are fully aware of the requirements and phasing to correctly waterproof the structure.

The dangers of not having a Waterproofing Strategy in place are well illustrated below with this extract from a document detailing LABCs requirements:

The provision of a Structural Waterproofing Design Philosophy document at this early stage is often overlooked or incorrectly considered as ‘not essential’.

But for Warranty purposes, the provision of a Structural Waterproofing Design Philosophy document by a competent person gives a greater clarity of the information, which then allows us, as early as possible, to establish the level of risk and complexity involved in the project.

Where afforded the opportunity to carry out such an evaluation, we can assist in avoiding issues on site. For example, a structural waterproofing proposal is provided in relation to an area of plant room considered critical to the building’s operation. The design details a Grade 2 environment for this area with a single system of waterproofing protection.

However, when the ground conditions are reviewed against the supporting Phase 1 and Phase 2 reports by us during the structural waterproofing evaluation process, we may consider them to present a high-risk water classification. In such an instance we may request the Waterproofing Design Specialist adjust their proposals to provide details of risk mitigation such as an additional system of protection to protect the environmental grade and lower the risk of failure.

If you’d like to discuss your requirements or need initial input on discharging an insurer’s particular conditions, or an assessment of both yours and their requirements, please get in touch for an initial discussion on an approach applicable to your particular construction project.