Many ground floor U-value calculations feature a simple build-up of materials, in layers that have consistent thickness and performance characteristics. However, structural requirements (such as foundation design) or on-site variables can introduce complexity to U-value calculations, and lead to doubt about the correct way of establishing a floor’s thermal performance. The Polyfoam XPS technical helpdesk … Read more
Year-on-year increases in the specification of our products can trick us into thinking that everybody knows, and wants to find out more, about extruded polystyrene (XPS) insulation in the smallest detail. Last month (May 2026) we exhibited at Futurebuild, and the questions posed by visitors to our stand were a useful reminder that, for many … Read more
Many continuing professional development (CPD) sessions offered by construction product manufacturers carry independent accreditation. Assessment by a third-party is designed to show that the session meets certain expectations – usually, that the content is neutral, educational and covers specific learning points, rather than being a biased sales pitch. The importance of quality CPD content cannot … Read more
The updated code of practice for flat roofing, BS 6229:2025, recommends an insulation thickness increase where the design lambda of inverted roof insulation is the same as the declared lambda. The new recommendation for a minimum 2.5% insulation increase replaces a controversial note in BS 6229:2018 that suggested insulation thicknesses may be increased by 10% … Read more
Following a successful exhibition in 2025, Polyfoam XPS will be at Futurebuild once again in 2026. The Hartlepool-based manufacturer of extruded polystyrene (XPS) insulation will have a stand at the event, which takes place on the 12th, 13th and 14th May. This year, Futurebuild is co-located with UK Construction Week, creating an even more compelling … Read more
Inverted roof systems – and water flow reducing layers (WFRLs) as part of them – must contribute to the performance of the roof across all stages of a building’s life. It is not enough to specify and install to deliver an inverted roof that performs at the moment the building is handed over, but not … Read more
The publication of BS 6229:2025 has introduced new recommendations for laying water flow reducing layers (WFRLs) as part of inverted roof build-ups. Among wide-ranging and significant revisions to the standard’s content, this highly specific area of guidance seeks to ensure the WFRL remains in place while installing the ballast layer that follows. New recommendations aimed … Read more
Thermal insulation is just one component of a flat roof build-up, so the required insulation thickness depends on the other materials specified with it. For example, if a roof build-up features a structural deck of metal rather than concrete, even if everything else is identical there can be a notable difference in the thickness of … Read more
Extruded polystyrene manufacturer, Polyfoam XPS, has created a brand-new resource for designers and specifiers. The Polyfoam Orange Book of XPS Insulation is a comprehensive guide to extruded polystyrene (XPS) and its performance characteristics. There are also pages of application-specific design guidance for flat roofs, ground floors and basements, swimming pools, and cavity insulation below damp … Read more
New thermal insulation solutions from Polyfoam XPS mean specifiers and installers can choose better lambda values for thinner ground floor constructions and flat roof designs. The improved Floorboard and Roofboard products offer a declared thermal conductivity of 0.031 W/mK (design lambda of 0.032 W/mK for inverted roof applications). With the capability to also produce new … Read more
