Liquid Roofing and Waterproofing Association (LRWA)

The Liquid Roofing and Waterproofing Association (LRWA) is a trade association in the United Kingdom for the liquid-applied roofing and waterproofing sector. It was founded in 1979. Its contact address is Roofing House on Worship Street in London, which it shares with the National Federation of Roofing Contractors. Its website is lrwa.org.uk.

Members include manufacturers of liquid waterproofing systems, contractors and installers, service providers and technical professionals.

What liquid roofing is

Liquid-applied systems are coatings or membranes applied as a liquid that cure to form a seamless waterproof layer. Types include polyurethane, polyester, PMMA (polymethyl methacrylate) and bitumen-based products, often reinforced with a fleece or mat. They are used for new flat roofs, refurbishing existing roofs, balconies, walkways, gutters and complex details where sheet materials are hard to fit. Hot-melt systems, applied as heated rubberised bitumen, are a related category often used under green roofs and paving.

Activities

• Codes of practice and guidance. The LRWA publishes codes of practice and technical guidance. It has issued an updated Hot Melt Code of Practice aligned with the 2025 edition of BS 6229, the British code of practice for flat roofs.
• Competence. It has published a competence framework for designing and specifying liquid roofing and waterproofing, and supports members with compliance under the UK Building Safety Act.
• Training. It offers accredited training for trainees, experienced workers and specific manufacturer products, including online courses.
• Standards. It works with other UK roofing associations to represent liquid systems in standards development.
• Product register. It runs the Liquid Roofing Finder, a register of products.
• Awards and events for members.

Context

In Europe, liquid-applied roof waterproofing kits are assessed under the European Assessment Document system (formerly ETAG 005). Other countries have their own associations for liquid waterproofing. As with any roof system, performance depends on correct surface preparation, thickness and curing conditions.