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PQ-20 C Paraquartz

Langley PQ-20 C Paraquartz Liquid Roofing System

The PQ-20 C (cold roof) system is part of the Langley Paracoat range of cold applied liquid waterproofing systems. Paraquartz is an advanced, single pack, high performance, moisture triggered polyurethane, quick curing, waterproofing system with skid-inhibiting surface for flat roofs, walkways and balcony areas that carries a 20 year* independently insured guarantee for both materials and workmanship.

When to Specify

This system is for refurbishment projects where a skid-inhibiting finish is required and existing systems are to be overlaid (avoiding costly strip-ups). Suitable for application to most common types of waterproofing including bituminous felt (BUR), mastic asphalt and single-ply.


(1a) Paraquartz Clear, 1000 microns, 0.75 kg/m² **

(1b) Paraquartz Granules, 0.7 to 1.2mm (sieve size), 5.00 kg/m² **

(2) Paraquartz Top Coat (Dark Grey), 0.75 kg/m² **

(3) Langley Embedment Fleece, 0.225 kg/m² **

(4) Paraquartz Base Coat (Red), 1.00 kg/m² **

      Overall thickness of (2), (3), (4) = 1500 microns **

(5) Existing Roof / Waterproofing System ***

Total System Weight = 7.725 kg/m² **

* 25 year guarantee available, see guarantee section
** Liquid coating product measurements are nominal
*** Specialist primer may be required


Extremely robust, seamless yet flexible roof covering.  Reinforced with glass fibre fleece.  Permanently elastomeric.  UV resistant. Skid-inhibiting finish.


  • Tensile Strength: 11.5 N/mm²
  • Shear Strength: 98.7 N
  • Elongation: 500% (un-reinforced)
  • Fire Rating: EXT. F.AB             BS 476: Part 3: 20004
                          Broof (t4)              EN 13501-5: 2005


Long term solution, life expectancy in excess of 20 years.


Paraquartz is a single pack high performance polyurethane elastomeric compound.  User friendly, quick and easy to install. No ‘on site’ mixing required.  Rapid curing, typically 2 hrs/coat (depending on ambient temperature).  Curing is moisture triggered.  Full range of supporting products. These include specialist primers and biocidal wash.


  • System carries a 20 year independently insured guarantee for both materials and workmanship.
  • Guarantee can be extended to 25 years with the application of an additional top coat. 
    Contact Langley for details.
  • Can only be installed by approved contractors to ensure product quality is maintained
  • Full range of accessories/supporting products, all included under a single comprehensive guarantee, includes: rooflights, refurbishment outlets, vents, lead-free flashings, edge trims etc.

Holistic Package

For users peace of mind, this system is supported by the full Langley package that includes: survey’s, condition reports and proposals, specifications, site monitoring and reporting, technical and design advice, guarantee inspections, all at no additional cost.

The above information is issued in good faith and without warranty and is intended as a guide only. The information comprises typical data and does not constitute a specification.