Why XPS is the ideal insulation for cold roofs

With the drive to more efficient and eco-friendly buildings, the specification of roof insulation for inverted roofs has supported that focus. Sundolitt has seen an increase in the move towards green roofs and more recently the more unique blue roof application.

Inverted roofs are a type of cold flat roof where the insulation is installed above the waterproofing layer, therefore the insulation should be highly resistant to water absorption, able to maintain its thermal properties and structural composition – making XPS the ideal material for this roof construction. Extruded polystyrene is not affected by water immersion or repeated freeze/thaw cycles and any moisture is repelled by its closed cell structure.

Thermal performance is a crucial factor when selecting insulation for your roofing project. Sundolitt’s XPS resists water penetration thus maintaining the longevity of its thermal resistance (R-value) even in the toughest conditions. The low lambda values of XPS insulation helps improve thermal conductivity (k-value) which in turn reduces energy costs and environmental footprint. Committed to achieving lower U values across our standard range, Sundolitt boards are available with a ship lap edge preventing thermal bridging and reducing capillary action.

XPS has exceptional load-bearing characteristics between 200 kPa – 700 kPa making it ideal for weight-bearing applications such as inverted roofs. The material is certified to perform over the lifetime of the building, all in accordance with EN826 and EN13164. XPS is innate to the environment, fully recyclable and will not support fungal growth.

Green roofs

A green roof, or living roof, is a type of cold roof that can be covered with a shallow growing medium, planted with sedum for example or a full-blown roof garden with a variety of different sizes of shrubs and plants. Providing a visually more attractive finish, but equally roofs can be covered with gravel or paving slab ballast, a green roof can also reduce storm water, helping urban areas control the management of surface run-off.

XPS insulation is a cost-effective solution for a green roof as it withstands heavy loads as well as footfall from landscaped areas on the roof, if for example walkways are to be an integral roof feature

Blue roofs

A blue roof design utilises the roof construction for providing water attenuation capacity rather than quickly moving through the usual conveyance system. The water is released at a managed and controlled rate storing the rainwater as required, all as part of the overall Sustainable Urban Drainage Systems (SUDS) good practise policy, replicating the natural environment or in urban areas improving the built environment.

An ideal insulation material for a Blue Roof application, XPS not only provides the required thermal performance for the building but does not degrade or lose its integrity when submerged in water.Supplied in various thicknesses according to the specification, Sundolitt’s XPS is installed with a filtration layer and the can be overlaid with either paving or ballast.

Sundolitt XPS combines the loading capacity for weight-bearing applications with the advantage of maintaining its insulating performance even in an environment of rainfall saturation in the winter months. In the summer, blue roofs can help cool the building on hot days, reducing the dependency of ventilation or air-conditioning units.

Accreditations

As a manufacturer of both XPS and EPS insulation, Sundolitt is well placed to support clients with technical and design advice for all roofing projects. As a vertically integrated company Sundolitt ensures a cost-effective solution and shorten lead times as the bulk of our raw material is manufactured in house. Sundolitt offers the most comprehensive single point accreditation for its Environmental Management system ISO14001:2015 and value-engineered insulation products in the market.

All sites are accredited to the global Quality Management Standard BS EN ISO 9001:2015 showing comprehensive assurance of our commitment to quality in every part of our business. We also operate the EC Eco Management and Audit Scheme (EMAS) to ensure that all relevant laws and regulations are adhered to and continuous environmental improvements are achieved.

All Sundolitt XPS insulation products are manufactured in compliance with BS EN 13164: 2015 - the European standard for XPS thermal insulation products for the construction industry. Sundolitt XPS provides insulation levels which comply with Part L of Building Regulations for England & Wales and for Scotland Section 6 (previously Part J). Our self-extinguishing material is approved to DIN 4102-16.