Hydrostop AH+ liquid waterproofing was chosen as a better alternative to built-up roofing for installation to a new build Surrey County Council office development.
The local authority has been developing a brownfield site known as Gatwick Diamond Manor Royal which has been pre-let by South East Coast Ambulance Service and scheduled for occupation in September 2016.
Willmott Dixon’s Cobham Surrey office, which enjoys a strong reputation for commercial office development, has managed the construction of the £19milllion four-storey development, designed by award winning architects, HGP.
NFRC member, Southern Industrial Roofing of Portsmouth was appointed by the main contractor to undertake the 1800m2 roofing project.
Hydrostop AH+ is a wet-on-wet cold applied liquid waterproofing system that contains no solvents or isocyanates, with a very low VOC content.
The Hydrostop AH+ system was applied over a concrete substrate with a bituminous vapour control layer with Eurodeck liquid roofing board and cut to falls insulation.
For the installation process, the roof was first cleaned. Then a base coat of Hydrostop AH+ was applied, into which an 110gsm layer of polyester reinforcing fleece was embedded, whereupon it was immediately saturated with a second coat of liquid. Hydrostop AH+ is totally impervious to standing water, and as it is a single component liquid, it does not require a catalyst to be mixed into the product before use. The product comes with a 25-year guarantee which can only be offered by AccuRoof’s ACIS registered installers.
The Managing Director of Southern Industrial Roofing, Guy Rutherford said:
“Our installers like Hydrostop AH+ because it goes down wet on wet in a single pass install and there are virtually no fumes. The Hydrostop AH+ liquid roofing system is extremely quick to install. The system can be applied directly to the face of the specified insulation board and only requires the application of a 100mm wide self-adhesive jointing tape to the joints of the insulation, rather than having to apply an entire bitumen carrier membrane over the insulation as some other liquid systems do.”
AccuRoof has recently added a range of warm roof systems to include Cut-To-Falls, flat board, recovery board for overlays and one for specialist acoustic applications. Fully tested, these warm roofs have achieved a fire rating of BROOF(t4).
Surrey County Council believes this approach is a blueprint for other authorities to follow in using land assets to provide long-term revenue streams that will off-set cuts in other funding sources. As a follow-up, the council wants the Gatwick Diamond development which is close to the airport, to become a “Blue-Light” centre and is in discussions with other local emergency services on pre-letting the next phase of development.
Architect: HGP Architects
Main contractors: Willmott Dixon
