Our underfloor heating insulation boards are water resistant, insulated tile backer boards. They’re made of extruded polystyrene, with fibreglass mesh on both sides, which is embedded into a thin cement mortar to add durability. The boards are designed to withstand immense weight, around 30 tonnes per m², and are therefore ideal for use as under floor heating insulation. They're used to prevent heat escaping downwards into the substrate, which would otherwise be wasted, by reflecting the heat upwards. The result is decreasing wasted heat & energy as well and increasing heat up times and decreasing running costs. The boards are waterproof and are suitable for areas such as showers and bathrooms; they also provides a tacky surface which doesn't require priming to tile on. Also, WarmUp say that, during tests, overall heat up times were cut from over 2 hours to just 20 minutes.