“Often in the past, flat roofs were replaced only when they became porous and the building owner or occupier had to cope with leaks that could potentially cause major damage. Now, with the greater need for buildings to be more energy efficient, flat roofs are as likely to be upgraded due to excessive energy loss as they are for any other reason. This is the reason that expanded polystyrene (EPS) as an insulation material for flat roofs is currently becoming a preferred choice with contractors and specifiers.

Renowned for its durability and the fact that it retains its insulative properties for the lifetime of the building, EPS offers the reassurance that it will stand the test of time. The fact that the material recently achieved an ‘A+’ rating in the BRE’s Green Guide to Specification has only served to add to its popularity. Its green credentials are now without doubt as it has been proven to have low Global Warming Potential (GWP) as well as zero Ozone Depletion Potential (ODP), making it a strong sustainable choice.

When it comes to flat roofing, key considerations include material choice, thermal performance, method of handling, delivery to site, health & safety and speed of installation, so it is essential to have a planned approach to flat roof refurbishments.

With many buildings, such as schools, factories, hospitals and libraries in need of refurbishment of their flat roofs, now is the time to address the environmental credentials of these structures.

There is scope to significantly enhance insulation on flat roofs, which can increase a building’s energy efficiency by as much as 25 per cent. In many cases in the past, flat roof were often installed without insulation as building regulations were less stringent and the need to reduce the carbon footprint was unheard of.

Design requirements
The preferred roof construction is warm deck. Here, the insulation and vapour control layer are located above the roof decking, beneath the waterproof finish, which eliminates the problems of interstitial condensation.

There are three different types of products designed for a warm roof construction, all of which are made from expanded polystyrene. These are Jabroof boards – using a single-ply membrane for weatherproofing and Jabtherm and Jabdec boards – using a high-performance built-up felt or mastic-asphalt weatherproofing. All of these EPS products meet the current Building Regulations’ insulation requirements, such as part L1 and L2, for flat roofs in domestic and non-domestic buildings.

When upgrading a roof, it is important to take into account maintenance access or even open access to the roof area. Higher density EPS insulation boards should be used for roofs which will be subject to a high level of traffic, for example balconies and terraces. Standard density boards will be adequate for those roofs which will be subject to maintenance traffic only.

Like all roofing replacement projects, health & safety is of paramount importance, as are the requirements of offsite construction. The benefit of expanded polystyrene is that it can be manufactured to any thickness from 20mm upwards, which means that the boards can be quickly and easily installed in one single layer and contractors avoid having to join multi layers on site, which can often be time consuming and expensive.

Many of our boards are also supplied ‘cut-to-fall’, which again speeds up installation on site and provides the roof with the ability to disperse water. This is because standing water on a flat roof, over a number of years, can lead to issues with deterioration of the waterproof covering. With cut to falls, this is much less of an issue because the incline of the roof takes water away to the guttering, where it is removed.

As the energy performance requirements of existing buildings become more stringent, decisions relating to insulation choice for flat roofs are proving vital to the overall energy efficiency and carbon footprint. EPS as a material provides several advantages in that it is inert and waterproof, as well as offering excellent lifetime thermal performance. EPS is providing a viable solution for more contractors and architects as part of a shift to a more sustainable built environment.”

For more information on flat roof insulation, contact the Jablite sales team on 0870 600 3666 or visit the website www.jablite.co.uk.

For Technical Services please call 0845 601 2014 or email technical@jablite.co.uk