Due to ROCKWOOL stone wool insulation providing acoustic, thermal and fire-resistance properties, Kier Group specified a combination of ROCKWOOL flat roofing solutions on its new headquarters in Cambridge.
Kier Group is a leading property, residential, construction and services group, which invests in, builds, maintains and renews buildings operating across many sectors, including housing, defence, education, power, transport and utilities. Kier has a long-standing relationship with the Cambridgeshire area, having worked on 23 projects with the University of Cambridge, so it was no surprise when they decided to build their brand new three-storey headquarters in the Cambridge Research Park.
Although handling both the design and delivery process themselves, Kier worked directly with Cottenham-based roofing contractor, Voland Roofing, on this project. With a flat roof forming part of the design, both companies conferred that it required a roofing material that would provide exceptional acoustic management, good thermal insulation and a high quality finish that needed minimal maintenance. ROCKWOOL stone wool products suited the project’s specification perfectly and were the first choice for the construction specialist.
The primary challenge faced during this project was Kier’s stipulation that the new roof deliver high levels of acoustic performance. Kier wanted the roof to not only insulate against airborne sound, but also to reduce noise from the impact of raindrops on the roof. This meant that Voland Roofing had to achieve Rw 41 dB airborne sound reduction and Rw 52dB LiA rain impact noise. Alongside this, it was important that the roof provides long term thermal performance to keep the building warm and reduce heating costs.
Voland Roofing was responsible for installing ROCKWOOL HARDROCK Multi-Fix (DD) and HARDROCK Multi-Fix (DD) Underlay, with the ROCKWOOL Acoustic Membrane to cover the flat roof. Wayne Armstrong of Voland Roofing commented, “Having worked with these products previously, we knew that they would meet the brief for this project. These systems are quick and easy to install, which allowed us to turn around the project in good time.”
HARDROCK Multi-Fix (DD) was installed with a mechanically fixed, single ply system. This reduced the complexity of the installation, cutting time and cost on single and dual layer, mechanically fixed and fully bonded roof projects. The vast roof space on Kier’s new building is on two different levels. The ROCKWOOL solution had to be flexible enough to accommodate the change in level, and be installed smoothly and tightly around all the corners and edges. Thanks to the ease of installation of these products, this didn’t cause a problem for Voland Roofing.
The ROCKWOOL HARDROCK Multi-Fix products are renowned for their acoustic management properties, and when used in tandem with the ROCKWOOL Acoustic Membrane, offer a complete sound prevention system. Another added benefit is that this solution can be used with a variety of roof systems, so is very flexible.
Approximately 1100m² of the 60mm HARDROCK Multi-Fix (DD) and 1100m² of the 150mm HARDROCK Multi-Fix Underlay were laid across the roof, and then covered with 1100m² of 5kgm² ROCKWOOL Acoustic Membrane, supplied by SIG Insulation.
In addition to the acoustic properties, ROCKWOOL HARDROCK Multi-Fix products provided 0.039W/mK thermal conductivity, and offered a Euroclass A1 Fire Classification, the highest class for non-combustible products that do not contribute to a fire.
The ROCKWOOL products have provided the new Kier Construction offices with a complete roofing solution that more than satisfies the brief which Voland Roofing was set. They significantly reduce the airborne and impact noise and effectively insulate the building, which also helps to lower costs for Kier. “Our client is pleased with the end result, as we delivered a system that has fulfilled their brief”, concludes Wayne.
For its new office, Kier required a roofing solution that reduced noise, insulated the building efficiently, and achieves a long lifespan. ROCKWOOL provided a fully tested acoustic system that has not only met all the key requirements, but its non-combustible properties meet the highest European fire classification performance, achieving an A1 rating. The ROCKWOOL boards also provide a long term and stable thermal performance.