Sika Sarnafil single ply membrane was used to repair the leaking roof at Kirkgate market, Leeds.
Europe’s largest covered market, Kirkgate, has 800 stalls attracting over 100,000 visitors a week. As part of a £14m refurbishment to improve the market for the stallholders and the public, the leaking roof, extending over both the 1976 and 1981 halls, needed renewing while the building was fully operational.
The Sarnafil Plus team did the groundwork to secure the tender with the architect, asserting the benefits of a Sarnafil system, Sarnafil Plus technical support, and guarantee.
The original design specification called for the existing felt waterproofing to be removed back to the metal decking. However, this would cause massive disruption and with no guarantee of a watertight building.
Roofing contractors, Protech Roofing, suggested a mechanically fastened Sarnafil system that could be overlayed onto the existing substrate, ensuring the market remained open.
The nine-month project saw a team of between eight and 10 people working on the roof through all four seasons, including rain showers and temperatures of over 80°F (27°C.), without the project or waterproofing ever being compromised.
To begin, all loose chippings from the original felt roof were removed, and transported to ground level via a hoist system, and then into skips.
The initial survey revealed that some parts of the roof structure would not be strong enough to support heavy loads, so waste removal and new materials had to be placed and moved in a strategic manner. All materials were delivered and hoisted up and down carefully during designated times, to reduce disturbance.
Scaffolding and a crash deck were constructed underneath the roof, suspended from the steel structure of the building, to keep the market users safe.
Sarnavap 5000E SA a cold applied, self-adhesive vapour control layer was used to ensure temporary waterproofing for the market while the roofing work was being carried out.
The SarnaTherm insulation boards were mechanically fixed into the existing roof and installation of Sarnafil S327-15EL Light Grey membrane with stainless steel fixings created a durable, weathertight and aesthetically pleasing finish.
Sarnafil membranes are certified by the British Board of Agrément and to have a service life ‘in excess of
40 years’, giving the client confidence in the durability and longevity of the roof.
A further feature of Sarnafil roofing systems that appealed to the client was that the Sarnafil S327-15EL Light Grey membrane is cold applied – welded together using hot air rather than with a naked flame. The system can be used without restrictions as it meets the fire performance requirements of BS476-Part 3:2004 and BS EN 13501-5:2005.
Six rooflights over 51m long were replaced with SarnaLites, situated close together in rows, making sure that the market continued to benefit from natural daylight.
Sarnafil Plus visited the site regularly to offer support and advice, and to monitor installation quality and workmanship. A successful final inspection resulted in the issuing of a Sarnafil Plus guarantee.