Knowledge
What is an independent waterproofing consultant?
Why product-tied design is the root of most basement defect risk, and what independence means in practice.
Knowledge base
Knowledge
/ˈnɒlɪdʒ/ noun"What we've learned about keeping basements dry, shared freely with the wider industry."
Continual learning is one of our values, and so is sharing it. The full video series, long-form articles, positioning papers and white papers, gathered in one place. Most of it free, no signup. From the team at CLW, independent waterproofing specialists, including a contributing member of the BS 8102:2022 committee.
Two ways in
Ask the agent.
The fastest route to the Waterproofing Wisdom you need is usually our specialist AI. It reasons in BS 8102:2022: settle a grade, sense-check a quote, generate a risk assessment.
Ask the Wisdom AgentOr search the library.
Twenty-one episodes, twenty-one articles, two white papers. Find the one you need.
Waterproofing Wisdom episodes
Start at the beginning.
New here? Episode 1 is the place to start. Twenty-one episodes, filmed in the CLW office, 2024 to 2026.
Ep. 01 · How to procure waterproofing: 3 rules for success
Waterproofing Wisdom
The full series.
Every episode in the series. Each runs 8 to 15 minutes. Jump to the topic you need.
Ep. 01
How to procure waterproofing: 3 rules for success
Ep. 02
BS 8102:2022 revision. Key changes
Ep. 03
Waterproofing designer appointment: why timing matters
Ep. 04
Construction sequence for basement waterproofing
Ep. 05
BS 8102 Table 2 explained
Ep. 06
Design risk in waterproofing
Ep. 07
Competence in waterproofing
Ep. 08
Ground floor waterproofing
Ep. 09
Basements and major refurbishments
Ep. 10
Waterproofing design vs detail
Ep. 11
Case study: Salisbury Square
Ep. 12
Full-height waterproofing on retained ground
Ep. 13
Why a specialist contractor? Part 1
Ep. 14
What makes a specialist contractor? Part 2
Ep. 15
When waterproofing design is worse than useless
Ep. 16
Hidden risks of placing design in the SE scope
Ep. 18
Who should design waterproofing?
Ep. 19
Inversion thinking
Ep. 20
When to pay for waterproofing design
Ep. 21
Welcome Andrea: a new perspective
Ep. 22
Andrea's waterproofing journey, part 2
BS 8102:2022
The four performance grades, in practice.
Selecting the right grade is a decision about the space's intended use, not the basement's depth, not the contractor's preferred system. The grade governs everything downstream.
PCA webinar
Watch: the four performance grades, explained.
CLW's PCA webinar on BS 8102:2022 grade selection, the same framework we apply on every commercial basement. Watch it, and download the slides, on the BS 8102 hub.
Watch and download the slidesPerformance grade
G1A
Car parks, plant rooms, storage
Some seepage tolerated.
Read in depth
Performance grade
G1B
Storage with ventilation; non-critical plant
No water penetration; damp tolerated.
Read in depth
Performance grade
G2
Workshops, retail back-of-house, secondary commercial
No water penetration; some damp.
Read in depth
Performance grade
G3
Habitable, offices, retail, leisure, food, archives
Dry environment, controlled humidity.
Read in depth
Cluster 01
Independence
Why independent design is the foundation of credible waterproofing strategy.
Knowledge
Difference between a waterproofing consultant and a contractor
The structural conflict between designing and selling the same waterproofing system.
Knowledge
Risks of not appointing an independent designer
The named failure modes that follow when no one independently owns the waterproofing scope.
Knowledge
Why supplier warranties do not replace design
Warranties cover product failure. They do not cover the gap between specification and site.
Knowledge
The true cost of "free" waterproofing design
Contractor-led design appears to cost nothing. The cost lands later, on the developer.
Cluster 02
Standards and regulation
BS 8102:2022, the Building Safety Act, and the performance specification.
Knowledge
What does BS 8102 require?
The Code of Practice for protection of below-ground structures, read for the commercial development context.
Knowledge
Building Safety Act and waterproofing design
Latent defect liability, the Building Safety Case, and the documentation trail that supports both.
Knowledge
What is a waterproofing performance specification?
The contractual instrument that enables open tender and contractor accountability.
Cluster 03
Procurement and cost
How waterproofing is procured on commercial developments, and what consultancy costs.
Cluster 04
Construction-phase risk
Where defects originate, why they recur, and how design and monitoring eliminate them.
Knowledge
Why do basement waterproofing defects occur?
The patterns CLW sees repeatedly in dispute work, and the design-stage choices that produce them.
Knowledge
What is construction monitoring for waterproofing?
Independent site inspection during installation. Why it matters and what it involves.
Knowledge
Waterproofing design for basement car parks
Specialist considerations for car park slabs, drainage, and ventilation-influenced performance.
Knowledge
Waterproofing design for refurbishment and retrofit
Designing waterproofing into existing structures where ground conditions and as-built information are uncertain.
Knowledge
What makes a waterproofing design worse than useless
The diagnostic markers of a non-design that gives false comfort to the project team.
Knowledge
What is a waterproofing scope gap?
The absence of independent design responsibility, where most commercial basement defects originate.
Cluster 05
Roles, responsibility and RIBA
Who designs waterproofing, when they should be appointed, and what each RIBA stage requires.
Knowledge
Who should design waterproofing on a commercial basement?
Design responsibility for commercial basement waterproofing, read against current standards.
Knowledge
Who should design waterproofing on a commercial development?
Why the question matters more than it appears, and how to answer it on your next project.
Knowledge
Risks of placing waterproofing in the structural engineer's scope
When SE-led waterproofing design creates a scope gap rather than closing one.
Knowledge
What does a waterproofing consultant do at each RIBA stage?
Stage 2 strategy through Stage 5 monitoring. The staged input of an independent consultant.
Knowledge
When should a waterproofing consultant be appointed?
The right engagement window, and the rising cost curve of late appointment.
In-depth
White papers.
Long-form analysis on the commercial waterproofing decisions that produce the biggest downstream cost.
White paper
When to Appoint a Waterproofing Consultant, and What It Costs to Get It Wrong
The scope gap, the RIBA engagement window, what independence actually means, and what late appointment really costs.
White paper
Why Leaving Waterproofing Design to the Specialist Contractor Is the Most Expensive Decision on a Major Basement Project
The design-and-install route appears efficient and consolidates responsibility. It produces the most expensive failures in the UK market.
For buyers and their advisers
Buying a home with a basement?
Have a waterproofing question?
CLW's team contributed to BS 8102:2022, has written extensively on waterproofing risk, and serves as expert witness on major disputes. We are happy to help.