XR4000 is a rigid polyisocyanurate (PIR) insulation board with high thermal performance. Available up to 200mm thick, low U-values can be achieved without doubling-up insulation layers. Celotex boards are lightweight and rigid; making them easy to handle, transport, and fit on site, and suitable for applications including: ● Ground floors - whether solid concrete, block and beam, or suspended timber joist, and including where underfloor heating is used. ● Timber and steel framed walls - between the studs. ● Pitched roofs - between the rafters. ● Flat roofs - in ventilated cold roof constructions, installed from inside the building. ● Other retrofit and refurbishment projects - lining existing timber and masonry structures to make them more thermally efficient.