Why choose Dryseal over ‘wet-lay’ GRP roofing systems?

Housing Association Garage completed November 2015
Housing Association Garage completed November 2015

Fast becoming the specification choice of a growing number of Housing Associations, Dryseal is the unique component based fibreglass or glass reinforced polyester (GRP) roofing system. Unlike ‘wet lay’ systems, the Dryseal system is supplied pre-cured and ready to install. All Dryseal GRP trims and membrane are manufactured under strict BS EN ISO 9001 and 14001 quality and environmental controls and then supplied via our network of fully trained Approved Contractors for installation on site.

Dryseal should not be confused with ‘wet lay’ systems, which comprise fibreglass reinforcement saturated with liquid resin hand laid on site. Wet lay systems have greater potential for error as the process relies on fair weather from the outset. Liquid resin containing a catalyst is applied directly to a completely dry new roof deck. Fibreglass reinforcement is then manually laid into the resin. The fibreglass reinforcement is rolled to fully saturate the mat and expel any air pockets in the laminate in a critical process called “consolidation”.

Common problems with ‘wet lay’ GRP installations.

  • The need to renew the roof decking boards on most projects.
  • An extra layer of plywood or OSB is necessary above the insulation for ‘warm’ roofs.
  • Too much catalyst added to the resin mix, leading to the cure being too fast and potentially brittle laminate.
  • Residual moisture in the roof deck can result in the cure process failing.
  • Too little catalyst added to the resin mix, leading to delayed curing of the lamination and project delay.
  • Temperature drop late in the day, potentially leading to un-cured top coat.
  • Un-reinforced deck board joints leading to stress cracking due to differential expansion rates between the roof deck and waterproofing membrane.
  • Expansion joints are often recommended on roofs above 30 m2.
  • Guarantees often only cover the materials, rather than the installation.

The benefits of working with Dryseal:

  • Re-roofing work using Dryseal can be carried out re-using the existing roof deck, if it is in good condition. This saves on labour, landfill costs and reduces the risk of water ingress during re-roofing.
  • ‘Warm roof’ installations are straightforward using standard flat roofing boards.
  • Lamination of pre-cured flat sheet joints much quicker than full ‘wet’ application.
  • Residual moisture in the original roof build-up will naturally vent out as Dryseal “breathes”.
  • Flexibility of installation allows better certainty of successful projects.
  • Thermal movement is catered for within the Dryseal membrane and fixing method, dramatically reducing the need for expansion joints.
  • Complex details are easily handled, due to a wide range of pre-formed trim options.
  • Full BBA certification covering un-restricted use under current Building Regulations.
  • Full technical and design support.
  • BBA certification covers ‘zero-falls’ installation – for terraces and green roofs.
  • Acceptable to the NHBC as a roof covering system.
  • ‘Secured by Design’ accreditation and recommendation as a replacement for lead or copper on Heritage projects.