Celebrating its 150th anniversary in 2019, St. George’s Weybridge – a Roman Catholic private day school in Surrey – marked the occasion with the introduction of an exciting new architectural development. Transforming its existing, functionally simple sports hall into an inspiring, beautifully designed facility, the College’s accommodation brief comprised a premiership level hockey pitch and six-court sports hall, as well as a strength and conditioning suite, dance studio and flexible multi-use areas for group activities, meetings, presentations, exhibitions, open days and ‘match teas’. Designed by global architectural practice Scott Brownrigg, the architect’s vision was to create a contemporary and timeless building that would inspire students to achieve their very best.

With plans including a stunning tree canopy-like roof structure draping over the internal spaces, the roof needed to achieve 30m clear spans across the main hall and the design needed to be clever and sensitive to the fact that the site’s location sits within the green belt. It also required a flexible and durable waterproofing solution to ensure the building leaves a lasting legacy for future generations of Georgians.


Scott Brownrigg designed a bespoke freeform glulam roof that curves in multiple directions. Computer modelling software allowed the architect to create and control this complex roof form in virtual reality, pushing and pulling it to blend into the landscape.

In need of a roofing product elegant and pliable enough to accommodate the complex design, lightweight enough to minimise the impact on the roof’s structure and cost effective enough to cover such a large area, Sarnafil G410-ELF lead grey single ply membrane was specified, along with Sarnavap 5000, 120m Sikaatherm G insultation board and Sika SolarMount-1. Sarnafil adhered décor profiles were built, allowing rainfall to be interrupted and guided across the roof, while Sarnavap HD SA was used on the high-pitched areas in order to provide more slip resistance than the foil-faced SA, offering substantial health and safety benefits.

St Georges College, Sika Sarnafil Flat Roof

Malone Roofing, the roofing contractor tasked with realising the architect’s vison for the roof, is a longstanding and experienced Sarnafil installer, while Scott Brownrigg is a regular specifier of Sarnafil. As such, the entire team was confident that Sarnafil single ply was the right fit for this unique roof form.

Sarnafil worked closely with the architects and contractors to develop a specification that not only had the correct U-values, but was also compatible with the Cross Laminated Timber roof build up and ancillary roof mounted systems used, such as Photovoltaics, Latchways, a built-in gutter and upstands for roof openings.  

Despite working through challenging weather, with Malone enduring a particularly rainy period, and a challenging design, with curves sloping up to 30 degrees in some areas, the project was delivered on time and to budget.

Exceptional design, impeccable installation and Sika Sarnafil’s robust guarantees all combine to ensure this timeless design will be protected and enjoyed for years to come.

Client: St. George’s College
Main contractor: Blenheim House Construction
Roofing contractor: Malone Roofing
Project name: St. George’s College Activity Centre
Location: Weybridge, Surrey
Area: 3500m2
Architect: Scott Brownrigg

St Georges College, Sika Sarnafil Flat Roof