Despite its 78m height, its coastal location, heavy rain and high winds, all the roofs of Beckley Point in Plymouth are covered by a 20 year warranty from BMI Icopal against any defects in workmanship or materials.
Providing up to 23 storeys of student accommodation, Beckley Point is not simply the highest building in Plymouth but the whole of the West Country. Yet, according to Stormforce Roofing, this was not the only challenge it had to overcome in order to safely install the robust roofs required to fend off the coastal climate.
Designed and built by Kier Construction on behalf of The Student Housing Company, Beckley Point has more than 12 roof areas, all at different levels, from five floors to 23 floors, with the highest having a steep pitch of 45o.
“All of these needed to be started at different times and meant that we were working on small roofs on multiple areas whilst other trades are working there,” comments Simon Kalas, the director in charge of the project for Stormforce.
Yet the height and the cost of ever getting back up there once the roofs were installed were the factors that defined the roof specification: it had to be what was in effect a ‘whole of life’ solution.
“The specification for the roof went through several iterations from being fully bonded with ballast right the way through to the final specification of mechanically fixed felt,” he says. “It had to be the right system for the roofs and take into account that they would never be accessible without spending a lot of money – the scaffolding would be prohibitive. So whatever we installed would have to last 40 years.”
This led to Stormforce virtually gold-plating the final specification – a mechanically fixed BUR (built-up roof) system with a mineral cap sheet – by reinforcing the mechanical fixing for the felt with adhesive on the insulation beneath.
A further difficulty was set in motion by the Grenfell fire, which showed that the existing façade did not meet fire protection standards. This was removed but the new cladding was installed during the roofing works, so the detailing of the upstands had to be completed ahead of the main roof, reversing normal procedures.
“Using the wrong cladding meant that scaffold and materials went on finished roofs and so we had to make good after,” adds Simon. This also meant that the project took far longer than the 10 weeks originally scheduled: Stormforce started work in December 2016 and finished May 2018. This also meant that some of the blocks were occupied by students who had booked their accommodation on the basis of the building having been completed by September 2017.
And that had a knock-on effect for Stormforce, says Simon. “Installation was in winter during high winds so work could not continue when the wind became too strong. The high winds meant that when working on scaffold at extreme heights all tools had to be tethered and we maintained a strict regime of making sure materials and fixings were kept in place.”
The main materials for the system were – Icopal Total Torch VCL, Icopal Thermazone Insulation and Icopal FireSmart Profiles. An SBS-modified bituminous membrane reinforced with an extra strong glass fibre fleece, Total Torch Vapour Control Layer provides a weatherproof temporary finish to the roof structure before the final waterproofing system is applied. Sandwiched between the vapour control layer and the Firesmart profiles and Thermaweld capsheet, the Thermazone Insulation boards provide highly efficient PIR rigid insulation that offering thermal conductivity as low as 0.024W/mK. Icopal’s unique FireSmart® technology produces capsheets that provide a fire protection layer, shielding the roof from both spread of flame and fire penetration, and are also 30% faster to apply than traditional torch-on membranes.
Other materials employed included Icopal Primer, Icopal FireSmart Thermaweld detail cap sheet, Tecnatorch Sand detail underlay, outlets, and Icopal PU Glues.
“Working with the Icopal specification meant that both Kier Construction and our team knew that the roof would be proof against both the extreme winds and also the risk of fire,” Simon adds. “The weekly inspections from the BMI Icopal specification manager reassures everyone that the project is being carried out as per the specification and the 20 year warranty also ticks the risk management box on these design and build contracts.’’