The insulation of roofs with inverted layers, in which thermal insulation is placed in the sealing layer, provides a number of advantages, especially when it comes to ensuring the optimum operating temperature of the waterproofing, protecting it from damage, and increasing the service life of the roof as a whole.

This roof structure is suitable for covering with gravel or a layer of greenery, or use as a parking area or a terrace. XPS PRIME panels, due to their special properties, such as compressive strength, high thermal insulation, low absorbability, and frost resistance, are a suitable material for this type of application.

Such roofs are classified as not spreading fire, and have NRO classification for roofs with inverted layers using XPS PRIME S and XPS PRIME D panels.




The use of XPS PRIME S and XPS PRIME D extruded polystyrene panels as a protective layer placed over a waterproofing layer ensures an adequate coefficient of heat transfer “U” thorough the partition as a standard, and brings many other advantages, the most important of which are:


  • prevention of excessive heating of the waterproofing layer exposed to increased temperature amplitude (from -20°C in the winter season to even +70°C in the summer season), causing cracking of the waterproofing in the case of a classic system of layers,
  • protection of the waterproofing layer against the harmful effects of frost – fitting thermal insulation made of XPS PRIME S and D panels over it ensures that the temperature on the surface of the waterproofing is constant and always positive,
  • XPS PRIME S and D panels also protect the waterproofing against UV rays, which significantly increases their durability,
  • elimination of the risk of damage to the waterproofing due to hail, wind-suction force, and maintenance work on the roof – the waterproofing is not exposed to mechanical external factors – it is protected by the thermal insulation laid on it,
  • elimination of the risk of water-vapour condensation,
  • elimination of the formation of blisters on the waterproofing, which acts as a vapour-proof layer,
  • allowance of the possibility to assemble layers of the partition in practically all weather conditions,
  • guarantee of an appropriate indoor microclimate,
  • reduction of the amount of water discharged into the sewerage system,
  • reduction of the noise coming from the outside to the inside of the building.

Please contact us if you are looking for technical support or more detailed information.