Roland Jackson, Commercial Director of Soprema UK, the specialist in building envelope solutions, discusses the importance of combining waterproofing performance with acoustic properties, extended service life and low maintenance when specifying school roofs.
When specifying school roofs, the priority considerations are usually cost and service life. The cost and disruption of refurbishing a roof in any environment is onerous, but in a school setting, where budgets are limited and there are operational and safeguarding issues when work is required on site, a low maintenance robust solution is critical.
But the build cost and longevity of the roof are not the only considerations for new build school projects. The roofing system should be compatible with the structure, fast and easy to install in line with challenging school build programmes and compliant with all relevant standards. It should also be tested as part of a complete roof build-up, specified as a single solution with a joined-up warranty, to ensure it delivers safety and performance, backed by technical support.
But what constitutes performance in a school roof and how might the wrong choice adversely affect the school environment?
Single ply roofing systems are often the system of choice for school build projects because they are easy to install and offer speed of installation, particularly over large roof areas, with the flexibility to enable installation on curved surfaces. Ease and speed of installation also offers cost benefits, due to a shorter programme and reduced labour requirements.
Single ply systems are also ideal for use with the type of lightweight structures used to construct most school buildings. But it’s important to note that compatibility with lightweight structures involves more than loading. Sound can reverberate more easily through lighter structures, creating issues with acoustics from noise outside and from reverberation caused by sounds within the building. The design style of many schools, with large atriums and open plan spaces, may exacerbate issues with noise, so it is essential to consider the acoustic properties of the roof build-up as part of a complete assessment of performance throughout the service life of the roof covering.
Why are Acoustics so Important in Schools?
Schools are rarely quiet places, but for learning activities, there is a need to impose quiet without the disruption of noise travelling from elsewhere in the building or from outside. The Government’s BB93 Building Bulletin explains minimum performance standards for the acoustics of school buildings, but specification should always take into consideration the particular building design and location. For example, a school situated in a busy urban area, under a flight path or adjacent to a railway line, will need to be able to control much more demanding levels of external noise than a project in a rural location.
BB93 also outlines the different levels of acoustic performance required in various areas of the school building. Part of the difficulty of specifying for contemporary school buildings, however, is that spaces are often designed to be flexible or multi-purpose. Moreover, it is possible that the requirements of the school may change over time, within the service life of the roof build-up, causing some locations to be repurposed to environments that need greater acoustic control. As a consequence, it is wise to ensure maximum acoustic protection across the entire roof where possible.
Optimum Build-up Performance
An acoustic insulation installed onto the substrate prior to installation of the thermal insulation is the most effective way to limit external noise and prevent reverberation within the building. This provides additional mass to the insulation layer, absorbing noise from outside the building, including rain, traffic or aircraft noise for example, along with reverberation from within the building.
Soprema has tested a complete roof build-up, comprising Soprema Tecsound, a synthetic acoustic membrane based on a high-density polymer, A1 non-combustible stone wool insulation and the Soprema Flagon extruded PVC waterproofing membrane. The acoustic membrane also performs the role of the air and vapour control layer, reducing the number of stages involved in the installation.
The roof build-up is suitable for lightweight structures, including modular builds, and offers flame-free, odour-free installation with fewer laps thanks to the increased width of the extruded membrane sheets. When a fully-bonded Flagon single ply is used in combination the Tecsound acoustic membrane, the specification avoids the need for any mechanical fixings, which can sometimes provide a path for sound to reverberate, maximising the benefits of the build-up. The Tecsound acoustic solution can even be used as part of the wall build-up to further enhance protection from nuisance noise.
Top Class Schools
With so many areas of the UK struggling with high demand for school places, there is significant construction activity within the education sector for both new build schools and extensions. Specifying a roof build-up that combines long-term protection against the elements, high levels of acoustic control and low maintenance is key to creating top class schools.