Hydrostop AH-25 offers fast track solution at Gatwick Diamond “Blue-Light” offices

Project: Gatwick Diamond Manor Royal
Client: Surrey County Council
Architect: HGP Architects
Main contractors: Willmott Dixon
Roofing contractors: Southern Industrial Roofing
Liquid waterproofing system: Hydrostop AH-25

Hydrostop AH-25 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-25 is a wet-on-wet cold applied liquid waterproofing system that contains no solvents or isocyanates, with a very low VOC content.

The AH-25 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 AH-25 was applied, into which an 110gsm layer of polyester reinforcing fleece was embedded, whereupon it was immediately saturated with a second coat of liquid. AH-25 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 SIG’s DATAC accredited installers.

The Managing Director of Southern Industrial Roofing, Guy Rutherford said:

“Our installers like AH-25 because it goes down wet on wet in a single pass install and there are virtually no fumes. The Hydrostop AH-25 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.”

SIG Design & Technology 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.

Hydrostop AH-25 offers fast track solution at Gatwick Diamond “Blue-Light” offices case study

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