The challenge
In November 2018, Triflex were invited to provide a bespoke waterproofing specification for the roofs on the social housing blocks at Riverbank, Staines-upon-Thames. A member of the Triflex Authorised Contracting Partner network had been approached by property consultancy John Rowan and Partners, who were operating on behalf of the end client A2 Dominion. A2 Dominion required an intrusive survey to determine the scope of works for a fully Part L compliant thermal upgrade to the existing waterproofing system.
The existing 1,800m² warm roof system consisted of a bituminous mineral felt waterproofing membrane, cork board insulation, vapour control layer, cementitious screed and a concrete deck.
An initial site survey was conducted, and it was found that the existing bitumen felt system had reached the end of its serviceable life. It was clear due to many liquid coating remedial repairs, that the roofs had a history of moisture ingress.
Intrusive core samples were taken to determine whether the existing system was in a suitable condition to be overlaid, and to identify what the current thermal performance was. However, core samples revealed that the cork board insulation was saturated due to failure of the existing system and would require replacement.
The solution
Triflex were specified due to the advantages of our Triflex PMMA (polymethyl methacrylate) waterproofing systems. Traditionally bitumen mineral felt has been the go-to, tried and tested membrane for refurbishment of flat roofs in the social housing sector. However, Triflex PMMA waterproofing resins provide many significant benefits during installation over this traditional material, such as; flame free installation, health and safety benefits, reduced risk, reduced insurance premiums, rapid curing process and reduced time on-site.
Triflex ProTect warm roof was the specified main area waterproofing system and Triflex ProDetail was specified for all detailing works, including gutters, penetrations, pipes and upstands. Both systems are fully reinforced, seamless waterproofing systems, which are self-terminating with no requirements for the use of termination bars or protective cover flashings. Furthermore, the advanced Triflex PMMA resin chemistry means that both of these systems cure extremely quickly, being rainproof in 30 minutes and trafficable in 45 minutes.
The Triflex ProTect warm roof system is fully compatible with the specified 130mm Triflex PIR insulation, ensuring a strong bond and total adhesion. The specified insulation brought the roof refurbishment in line with Part L of the Building Regulations and achieved the 0.18 W/m2K U-value requirements. Both Triflex ProTect and Triflex ProDetail are installed utilising a wet-on-wet application process, minimising time on-site and cost. In comparison to wet-on-dry systems there is no need to wait for the previous layer to fully cure, which can take as long as 6-8 hours. This also eliminates any cross contamination and inter-layer adhesion issues.
The main contactor Mulalley awarded the project to Ifield and Barrett, an experienced Triflex Authorised Contracting Partner. The speed of cure of both systems coupled with the experience of Ifield and Barrett allowed this warm roof refurbishment to be completed on schedule and with a high level of workmanship.
