September 2003


Seven mixed-use blocks at Sandhurst's Royal Military Academy have had their leaking flat roofs fixed permanently thanks to Ash & Lacy's Ashjack over-roof conversion system. Installed by approved contractor Rooftech 2000 for main contractor McNicholas plc, a lightweight Ashjack framing system was used to create a pitched roof structure. Over-clad with single-skin profiled steel in goosewing grey, the Ashjack system not only provides a permanent solution for the removal of any further water, but also dramatically upgrades the aesthetic appearance of each block. The phased project, which commenced earlier this year, is due for completion during September.

The original roofs had been constructed with a concrete deck overlaid with screed and mastic asphalt weatherproofing. Repairs had been carried out many times to the weatherproofing layer, which had reached the end of its design life a number of years ago.
The various coatings and patches however, had only provided a short-term solution and the roofs had continued to leak. The situation was compounded further by drainage outlets positioned in the centres of the roofs, which were not providing an adequate mechanism for the removal of water. By opting for an over-roof conversion system, drainage could be moved to the outside of the building thereby eliminating the potential for any further problems.

As the existing roof was structurally sound, a lightweight Ashjack propped rafter conversion system was selected and fixed directly to the roof deck. This type of system provides an extremely cost-effective refurbishment option and is ideal for creating steeper roof pitches. With an excellent strength to weight ratio (typically 5kg/m²) this system is strong enough to support any type of over cladding from standing seam, composite panels to tiles and slates. The opportunity was also taken to upgrade the thermal performance of the existing roof by laying glass fibre quilt directly over roof deck to meet the currently required U-value of 0.25 W/m²K. This not only 'future-proofs' the building against new regulatory legislation but can significantly reduce heating bills and energy consumption, which in turn lowers the running costs of the building and reduces CO₂ emissions.

Commenting on the selection of an Ashjack over-roof conversion system, Colin Jackson, Managing Director of Rooftech 2000 said:

"We put forward an Ashjack over roof system for this project, as it is a cost-effective and fast track method of refurbishment that not only incorporates a roof pitch, but also allows drainage to be moved to the outside of building. As an approved contractor we have partnered with Ash & Lacy many times and enjoy the levels of design and technical support provided which are second to none".

Developed by Ash & Lacy in 1988, Ashjack was the first structural lightweight over-roof conversion system in the UK. Quick and simple to assemble, Ashjack has provided a permanent refurbishment solution on buildings throughout all sectors of the construction industry. From a commercial point of view the life of the building is considerably extended, maintenance is reduced and the upgraded aesthetic properties add additional value to the property. Supported by a network of approved installers Ashjack is available in a range of systems, which include a clear spanning option that is designed for use on buildings where the existing roof is suffering from severe structural degradation.