How Does Waterproofing Procurement Work on Commercial Developments?

Direct answer

Waterproofing procurement on commercial developments works best when it follows a structured sequence: an independent waterproofing consultant produces a performance specification, that specification is used to invite competitive tenders from qualified specialist contractors, the tenders are evaluated on both technical merit and price – against objective criteria, and a specialist contractor is appointed with clear scope and accountability. Without this structure, waterproofing procurement defaults to opaque pricing, incomparable bids and scope gaps that generate disputes.

Full explanation

Waterproofing procurement is one of the least well-understood processes on a commercial development, and getting it wrong means consequences that are disproportionate to the relatively modest value of the waterproofing package within the overall project cost.

The problem with unstructured procurement

On the majority of commercial developments in the UK, waterproofing is not procured through a structured process. Instead, the main contractor includes waterproofing within their general sub-contract packages, approaches two or three preferred suppliers and receives proposals that vary in scope, specification and risk allocation. These proposals are not comparable because there is no common specification against which to evaluate them. The client – or the project manager acting on the client’s behalf – has no visibility of what is actually being proposed, what is excluded, or how the price relates to the risk being transferred.

This unstructured approach consistently produces poor outcomes. The contractor selects the lowest-price proposal, which typically reflects the narrowest scope. Scope gaps are not identified until construction, when they become change orders. The client pays more than they would have through a structured procurement process and receives a less robust waterproofing solution.

How structured procurement works

Structured waterproofing procurement begins with an independent waterproofing consultant producing a performance specification during the design phase. This specification defines what the waterproofing must achieve – without prescribing specific products – and creating a level playing field for tender.

The specification is issued to a pre-qualified list of specialist waterproofing contractors. Pre-qualification criteria typically includes relevant trade body membership, evidence of CSSW-qualified site supervisors, a track record on comparable commercial schemes and adequate insurance cover. The pre-qualification process itself adds value by filtering out the contractors who lack the capability to deliver.

Tendering contractors submit proposals demonstrating how their proposed system meets the specified performance requirements. Because all tenderers are responding to the same specification, the bids are directly comparable on scope, system performance, programme and price. The independent consultant then evaluates the submissions and provides a technical recommendation to the client.

Packaging decisions

A key procurement decision is whether to package waterproofing as a stand alone specialist package or include it within the main contractor’s scope. There are valid arguments for both approaches. A stand alone package gives the client direct contractual control over the specialist contractor and clearer accountability. Inclusion within the main contract simplifies contract administration and places co-ordination responsibility with the main contractor.

The choice depends on project-specific factors – including the complexity of the waterproofing, the client’s appetite for direct management and the main contractor’s experience with specialist waterproofing packages. The independent waterproofing consultant advises on this decision as part of the procurement strategy.

The role of Pre-Construction Services Agreements

On complex developments, a Pre-Construction Services Agreement (PCSA) can be used to bring a specialist waterproofing consultant into the project team before the main contract is let. The PCSA enables the consultant to contribute to design development, buildability review and detailed programme planning. This early engagement improves co-ordination and reduces the risk of construction-stage surprises. The PCSA is not a commitment to appoint the consultant for the main works – the client retains the right to competitively tender the installation package.

Tender evaluation

Effective tender evaluation for waterproofing requires specialist knowledge. The consultant will assess each submission against the performance specification, checking for system compatibility, adequacy of risk response, completeness of scope, realism of programme, and appropriateness of the proposed quality assurance regime. Price is evaluated in the context of scope – a low price with a narrow scope is not the same as a competitive price with comprehensive coverage. The consultant’s evaluation report gives the client an informed basis for decision-making, rather than a default to lowest cost.