Technical Guidance


All LRWA manufacturer members have dedicated technical advisory staff and are able to provide advice and support including:

  • Specifications
  • Drawings
  • Calculations
  • Site visits if required

For more general enquiries please contact the LRWA please contact us

Technical Site Support
LRWA manufacturer members provide assistance on site either at the request of the contractor or as part of their guarantee procedure. Such site support should be properly documented and any proposed actions followed up and signed off in accordance with the manufacturer’s quality control procedure.

The LRWA are proud to support the NFRC’s Competent Roofer Programme.

Competent Roofer

Guarantees and Lifespans

All LRWA members must offer a minimum 10 years materials guarantee. Most manufacturers however offer material and workmanship guarantees up to 25 years, based on the system specified under the terms and conditions of their recommended contractor schemes.

The lifespan of the system will usually be well in excess of the guarantee period. In many cases the life of the system can be extended by the application of additional coats at the end of the guarantee period.

Practical things to think about when pricing a project using a liquid applied waterproofing system:

  1. The type and condition of the substrate is the only part that can be variable when pricing liquid applied waterproofing. The rougher the substrate the more material will be required. Most manufacturers base specifications on:
    • Smooth – coating onto existing coated surfaces/asphalt or black felt.
    • Medium – Mineral surface felt or easily scabbled surfaces.
    • Rough – Difficult de-chipped roofs or heavy mineral surfaced felt.
  2. What type of primer is required if any (dependent on substrate and manufacturer’s recommendations)?
  3. Is there a reinforcement required within the liquid applied roofing system that you have chosen?
  4. Coverage rate of the topcoat(s) will be specified by the manufacturers.
  5. Is the roof clear of obstruction and penetrations?
  6. Are there an abundance of obstructions and penetrations (the busier the roof the slower the progress – but using a liquid will be significantly quicker than using a sheet)
  7. Thought must be given to the termination details and to any cost considerations that may occur with the provision of chases, trims, termination bars, and mastic pointing.
  8. Include for the cost of night seals.
  9. Because of the nature of liquid applied waterproofing the waste factor is minimal.

Other general considerations

  • How high is the roof?
  • Access for both men and materials.
  • The provision of safe site storage.
  • If the existing roof system is to be removed, how will you dispose of the material?
  • How will you get the new materials onto the roof?
  • Skips and the removal of all waste – ie: tins, insulation and off cuts etc.

For any technical queries please contact us at