BriggsAmasco designed and installed an innovative waterproof system to ensure the roof of a new major online retailer distribution centre was fully protected against the elements in an extremely tight delivery programme. The work, which was carried out at at a warehouse and distribution centre in Swindon, allowed the huge building to open for business on the client’s desired date.

The four-storey building covers in the region of 166,000m2 – the equivalent of six-and-a-half football pitches – making it the second-largest warehouse building of its type in the UK. The client’s brief for the warehouse’s 4,700m2 roof was for BriggsAmasco to deliver a waterproof system that was capable of accommodating a large amount of vital plant equipment, provided excellent drainage to rainwater outlets and offered an appropriate level of thermal performance in order to achieve a target U-value. It also needed to be installed within a strict six-week timeframe to protect interior works and keep the business on track. Just as importantly, the approved waterproofing system needed to benefit from a comprehensive warranty that covered materials, design and workmanship.

In conjunction with IKO, BriggsAmasco designed an inverted waterproof system for the warehouse’s roof. The IKO Permatec hotmelt solution was initially specified with IKO Enertherm XPS PLUS insulation as part of the build-up. The rigid polystyrene board provided the desired thermal performance for the roof’s targeted U-value, but its overseas manufacture posed a problem. Travel restrictions meant the insulation’s UK importation could not be completed in time for the waterproofing project’s start. It led to BriggsAmasco and IKO redesigning a waterproofing system that comprised alternative insulation without compromise to the targeted thermal performance.

The redesign was carried out using a weighted calculation and resulted in the specification of IKO XPS Enerthrem, which is manufactured in the UK and was available in just two weeks following its order. In terms of redesign challenges, the cladding had already been installed by another company. Additionally, the upstand FFL around the perimeter was below 150mm after finishes, requiring its redesign to a weighted calculation involving 170mm insulation in order to achieve the above 150mm finishes.

In terms of workmanship, BriggsAmasco installed the IKO Permatec hotmelt roof system to the warehouse’s concrete deck, with stone paving providing a smooth, robust finish. It was a far from straightforward installation, however. A huge amount of plant, including extractor fan ducting, needed to be accommodated by the hotmelt waterproofing. This was no easy task due to the logistics involved. However, BriggsAmasco installers overcame such issues with the application of some full-proof virtues: good planning and hard work.

BriggsAmasco installed the hotmelt waterproofing using an array of mixers, all of which needed to be transported to the four-storey warehouse’s roof. A number of large-sized cranes were procured to transfer the equipment and about 400 tonnes of ballast, with their reach needing to span pipework trenches that had been dug at the foot of the warehouse building.

Due to the site’s location and the amount of waterproofing material involved, BriggsAmasco created a delivery schedule to ensure drop-off times did not interrupt other trades’ work programme. This also ensured materials were used when needed, thus spare products were not left around the site to potentially create a health and safety hazard. A lack of effective storage space could also have led to materials being damaged or disintegrating in poor weather.

With such a large roof area to cover, BriggsAmasco’s installation teams worked out-of-hours to ensure the waterproofing was completed on time. Quality and workmanship would not be sacrificed to meet the tight deadline. For example, BriggsAmasco’s installers carried out peel tests on every 20m2 of waterproofing completed to ensure the hot melt solution was bonding effectively to the concrete deck.

As part of BriggsAmasco’s all-round service provision, teams also carried out electric testing to confirm the roof’s leak-free performance post-waterproofing. This was also crucial to the system’s 25-year, single-point warranty.

Thanks to BriggsAmasco’s design expertise – in conjunction with IKO – and the skills and diligence shown by its installation team, the project was completed within the stipulated six-week timeframe. Ensuring many thousands of customer orders were met in time.



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Hot Melt