SIKA SARNAFIL EXPLOSIVE SUCCESS FOR ROYAL GUNPOWDER MILLS HERITAGE ROOF REFURBISHMENT
November 2019

A historic and archaeological treasure, the Royal Gunpowder Mills heritage site in Waltham Abbey, Essex, has been given a new lease of life with a stunning and sympathetic roof refurbishment.
Consisting of listed buildings, ancient monuments and natural aspect features, the site is a well-loved attraction. A busy hub of activity, it attracts thousands of visitors every year, with exhibitions and a programme of hands-on activities for school groups.

With previous roof coverings across the site's buildings close to derelict, a new roofing system was needed that would both guarantee a durable solution and fit with the aesthetic of the heritage buildings. To meet those needs, Sika Sarnafil G410-15EL FSA Lead Grey was specified alongside Sarnavap 1000E air and vapour control layer.

The high-quality roofing system was chosen after the project's main contractors Courtenay Builders Limited were impressed with the results from similar Sika Sarnafil projects. They also entrusted Contour Roofing with the specification and installation after seeing its award-winning track record with Sika Sarnafil.

As a site once home to tonnes of explosives and with visitors in throughout the refurbishment, the project proved challenging, requiring extensive attention to health and safety. A strict ban on naked flames and hot works meant that the plywood boards had to be primed immediately after installation and before exposure to any wet weather. The specification therefore considered this and the original system, which would have needed a completely dry substrate, was switched to a loose laid polyethylene air and vapour control layer that was more equipped for a faster installation in the expected conditions.

Further challenges were met due to the 45-degree pitch of the roof. Roof ladders had to be used to allow workers access to the complex angles and achieve a seamless finish, using Sarnafil membrane and bespoke Sarnametal flashings at abutments, changes of angle and ridge angles.

Although time consuming work that required the utmost skill to ensure the roofs were completed to the highest standards, the project was kept on track. With Contour's contract manager making daily site visits, coupled with regular site visits from Sika Sarnafil Technicians, the project finished a week early.

Jonathan Woods, managing director at Contour Roofing, says: "This was a particularly interesting roof refurbishment with unique and complex challenges due to the nature of the site. However, by ensuring we had the right team in place with relevant experience, and the added support from Sika, we were able to complete the installation a week early while still providing an excellent finish that wowed the client."

Securing a 20-year Sarnafil guarantee, the newly refurbished roofs have not only met the client's need for a stunning aesthetic, but have also provided a durable weatherproof roofing system – upholding the heritage charity's mission to conserve the site for the benefit of the general public.