A challenging and high-quality installation of three new warm roofs on the plant rooms of the Hatfield Tunnel in Hertfordshire saw Itech Roofworks – working in association with BMI Icopal – shortlisted in the Cold Applied Liquid Waterproofing category in the National Federation of Roofing Contractors’ 2021 UK Roofing Awards.
Close collaboration between the technical team at BMI and IMA member Itech Roofworks produced a uniquely effective answer to the challenge of refurbishing Pier 6 at Heathrow’s Terminal 3. Originally built in 2006, Pier 6 is designed for the Airbus A380 superjumbo, so the scale of the project was massive
BDC 319 : Aug 2024
A challenging and high-quality installation of three new warm roofs on the plant rooms of the Hatfield Tunnel in Hertfordshire saw Itech Roofworks – working in association with BMI Icopal – shortlisted in the Cold Applied Liquid Waterproofing category in the National Federation of Roofing Contractors’ 2021 UK Roofing Awards. The awards were staged on November 5th 2021. Part of a scheme to upgrade the services for the 1,200m-long Hatfield Tunnel in Hertfordshire, which carries the A1(M) beneath the Galleria Shopping Centre, Itech was able – by meeting stringent installation and quality standards – to achieve a 20-year system guarantee from BMI Icopal for the three new roofs. As well as reducing whole-life costs and disruption to road users, delivering this level of longevity also will also reduce carbon emissions over the lifetime of the tunnel. The overall project was to upgrade the air conditioning (AC) and mechanical and electrical plant for the tunnel, involving the demolition and reconfiguration of central risers, extracts and tunnel services. As part of the upgrade, the failing flat roofs of the north, central and south plant rooms had to be stripped and re-roofed. Itech Roofworks was contracted by CBS, a Tier 2 Infrastructure company, to undertake the £250,000 project, comprising 1,750m2 of roofs. CBS’s client was highway maintenance consortium Connect Plus Services. Having stripped the failed roofing material from the concrete deck, Itech applied Siplast Primer followed by a bituminous carrier membrane. Next came the insulation, 30mm Thermazone Roofboard, which has a low thermal conductivity of just 0.24W/mK, followed by BMI Icopal SA Primer and Pyrobar Carrier Membrane. Itech then installed the full BMI Sealoflex Prima System: Sealoflex Prima 2-Part Primer, then a base coat of Sealoflex Prima Waterproofing Coating with Sealoflex Prima Reinforcing Fabric (embedded in the base coat), followed by a topcoat of Sealoflex Waterproof Coating. Anti-skid walkways were created for future maintenance purposes. BMI Sealoflex Prima benefits from accelerated curing, allowing it to be used at lower temperatures. Completely cold-applied, solvent-free and with no unpleasant odours make it more user-friendly for the installer. From an installation perspective, each of the three flat roofs posed their own challenges but common amongst them was the need to address the complexities posed by the upstands, vents and hatches that are typical features of a plant room. Making these waterproof involved detailed and accurate work on both the vertical and horizontal plane. The roofs also feature very slim gullies and any works had to make sure that the narrow apertures of the gullies were not closed or blocked by extraneous material. Overflows were installed to each roof. In planning the works, it was important to minimise the risk of disruption to the tunnel’s users. There were limited and separate windows – four weeks for each roof – in which Itech could carry out the roofing works which had to coincide with the stripping and renewing of the AC equipment and the other plant. Itech installed temporary roofs over each of the plant rooms so that both their operatives and those working inside the plant room could work productively whatever the weather. With limited space for storage of materials, just-in-time deliveries had to be carefully scheduled to meet the programme of works.
Close collaboration between the technical team at BMI and IMA member Itech Roofworks produced a uniquely effective answer to the challenge of refurbishing Pier 6 at Heathrow’s Terminal 3. Originally built in 2006, Pier 6 is designed for the Airbus A380 superjumbo, so the scale of the project was massive – 6300m2 of roof. The main contractor, Mace, appointed Itech Roofworks to remove the existing single ply, replace damaged sections of plywood, build bunding and subsequently weatherproof with the Sealoflex Ultima liquid system. A working airport such as Heathrow needs products that can be installed without affecting its operations, so Sealoflex solvent-free liquid-applied waterproofing and FireSmart Pyrobar Carrier Membrane were specified. Sealoflex Ultima is virtually odourless when it is applied while FireSmart Pyrobar is self-adhesive and can be installed very quickly once the existing single-ply membrane is stripped out. The BMI technical team were tasked with supplying a roofing system with improved fire performance characteristics. BMI met this challenge and developed a bespoke solution for this specialist application; by incorporating BMI Icopal’s innovative FireSmart technology to the specific bituminous and liquid elements of the system. “Both of these are bespoke solutions devised especially for this project,” explains Simon Ashworth, Synthetics & Liquids Product Manager. Simon had surveyed the roof with Construction Director Hayley Reynolds and found that several sections exhibited signs of long-term water damage and required replacing. Together they devised a working plan that allowed the damaged sections of plywood to be replaced without interrupting the day-to-day activities of the busy terminal. Use of the Pyrobar Carrier layer permitted a swift removal and replacement of the existing single ply, constantly maintaining the waterproofing integrity of Pier 6. Even when weather stopped the roofing teams working on-site, Itech Roofworks would look to pre-laminate replacement sections of plywood to minimise any lost time and future interruptions. Hayley Reynolds, Construction Director, says: “Mike Street and Simon Ashworth from BMI put a lot of work into the tender and their knowledge and support during the project was invaluable.” Hayley’s mission was to oversee the refurbishment ‘airside’ – right next to superjumbo jets landing and taking off – without disrupting the operation of the airport. “Managing logistics, getting materials and staff on and off-site while dealing with security and a working airport was definitely challenging,” says Hayley. “As main contractor, Mace co-ordinated the project to ensure that this was achieved smoothly so the programme ran to schedule.” The scale of the project meant setting up five teams, a total of 50 operatives, on both day and night shifts, every one of whom walked more than 10 km each day. Their task was also complicated by the plant rooms on the roof which meant they had to work around and under all the pipework and ducting, often on their hands and knees. The night shift stripped out the existing mechanically-fixed single-ply and installed FireSmart Pyrobar Carrier Membrane to the existing plywood substrate to create a weatherproof roof. The day shift then applied Sealoflex Ultima solvent-free waterproofing membrane if weather permitted or prefabricated the replacement sections. The restricted working spaces on the project posed significant challenges and required a highly skilled and experienced team of installers, a member of which went on to win Craftsman of the Year at the IMA Awards 2019 in recognition of the skills he demonstrated on this project. “The technical support from BMI that underpins the 20-year guarantee was very good,” comments Hayley. “We’re very familiar with the products yet it’s always important to ensure that you’re following best practice and getting the details correct.” To make sure that workmanship met the highest standards, each team had a quality manager who marked up drawings, wrote daily reports, and inspected all aspects of the installation. Now one of the world’s busiest airport terminals, catering for the world’s largest passenger aircraft, is covered by BMI and will not need anything but routine maintenance for decades. “We’re delighted with the result of this project as it truly demonstrates how we can add value for both the client and the roofing contractor,” says Simon. “We worked together closely and came up with a bespoke solution for a very challenging situation. We not only delivered a customised solution to meet the project needs for the client, but we also supported our approved contractor in developing a way of working effectively on a terminal that’s operating 24 hours a day, every day.” Ideal for situations where a site is operational during roofing works, Sealoflex Ultima solvent-free liquid-applied waterproofing is virtually odour-free so there is no disruption to the use of the building It is also very flexible, so that awkward penetrations to plant and equipment supports are easily waterproofed, and it benefits from wet-on-wet application, allowing faster application as the primary waterproofing elements can be applied in a single operation. The result is a robust and seamless surface finish. Simple to install, Pyrobar Underlay will waterproof exposed areas very quickly, so it lends itself to re-roofing projects where the existing membrane build-up is stripped out. This polyester reinforced SBS-modified bituminous membrane features an upper surface that is finished with Red Syntan acrylic coating. This coating reduces the weight of the material, making it easier to handle on-site whilst also providing the ideal surface to receive the Sealoflex Ultima liquid waterproofing system. For more details of BMI UK & Ireland’s flat and pitched roofing solutions, visit www.bmigroup.com/uk
