100mm Polystyrene Insulation

About

100mm polystyrene insulation boards are available in both expanded polystyrene (EPS) and extruded polystyrene (XPS) and are used across floor, wall, flat roof and specialist ground applications, with this thickness frequently specified where a higher thermal performance target demands greater insulation depth than thinner boards can deliver. Insulation UK is a specialist supplier of polystyrene insulation boards and sheets, stocking a comprehensive range of EPS and XPS products at 100mm. Types of Polystyrene Insulation Available at 100mm EPS boards at 100mm include standard white EPS across a full range of compressive strength grades, graphite-enhanced grey EPS, and compressible clay heave protection board for ground movement applications. XPS boards at 100mm are available from Ravatherm and Kingspan GreenGuard in multiple grades. Applications for 100mm Polystyrene Insulation Floor insulation is the most common application for 100mm polystyrene boards. Laid beneath a concrete slab on a well-consolidated hardcore base, 100mm EPS or XPS delivers a continuous thermal break between the ground and the finished floor, with standard EPS delivering an R-value of between 2.6 and 2.9 m²K/W depending on grade and grey EPS or XPS achieving up to 3.3 m²K/W. The boards cut cleanly with a sharp hand saw and are lightweight enough to handle without mechanical assistance, making them practical for both self-build and contractor-led projects. In practice, the achieved U-value for the finished floor will depend on the full build-up, ground conditions and slab specification, though 100mm EPS or XPS will contribute significantly toward meeting the Part L ground floor target of 0.25 W/m²K. In projects where a wet underfloor heating system is installed over the slab, the higher performance per millimetre of grey EPS or XPS helps to keep the overall floor build-up depth manageable. Wall insulation at 100mm suits cavity construction and internal dry-lining, and the same thickness is regular