Paroc Air is a simple and safe solution for making dry flat roofs. PAROC Air keeps the roof structure dry without any mechanical systems. The basis for this simple but effective solution is natural air pressure.

Effective roof insulation has three or four insulation layers. The lowest insulation layer forms a uniform base for the vapour barrier. The vapour barrier prevents moist air from leaking into the insulation layer. Due to the continuous stone wool base, the vapour barrier remains intact even during small structural movements.

The top of the intermediate insulation layer has a series of grooves which forms a network of ventilation channels. Porous stone wool with high vapour permeability doesn’t absorb the moisture into the insulation but allows moisture to move to the ventilation grooves where it is led out from the construction through ventilation hoods. 

On the top of the grooved insulation layer there is a thin and rigid stone wool board. It covers the ventilation channels and carries the load from human traffic during installation and maintenance.

Here are some examples of effective roof structures:

Flat roof, concrete, grooves 2
  • Roof membrane 
  • Mechanical fasteners 
  • PAROC ROB 80(t) (or ROS 50t)
  • PAROC ROS 30g
  • PAROC ROS 30 
  • Vapour barrier 
  • Supporting structure; Hollow-core concrete slab 
 Insulation solution with U value
 PAROC ROB 80t or 20 mm   -
 PAROC ROB 50t 50 mm
 PAROC ROS 30g 180 mm 190 mm
 PAROC ROS 30 170 mm -
 U value, W/m2K 0.09 0.14

Passive house construction

Passive house insulation requires a layer-insulation system where the under-layer of insulation is divided into three slabs. This solution is useful for Paroc ventilated roofs, where the upper intermediate layer has grooves in the surface. We recommend the ventilated solution as the number one solution, because it brings extra safety to the building.
Flat roof, concrete, grooves, passive house 
  • Roofing membrane
  • Mechanical fasteners
  • PAROC ROS 80t (d1)
  • PAROC ROS 30g (d2)
  • PAROC ROS 30 (d3 + d4)
  • Vapour barrier
  • Load-bearing concrete 
  Block of flats  
Recommended U-value   W/m2K 0.06 - 0.09
 d1  mm 20
 d2  mm 170
 d3 + d4  mm 180 + 180
Total insulation thickness  mm  550

According to the definition of a passive house provided by the Passive House Institute, the annual heating, cooling and primary energy demand should not exceed certain values. Although good thermal insulation plays a major role in achieving the Passive House standard, it alone cannot ensure compliance. The requirements for other building components and devices can be determined by various calculations tools, such as the Passive House Planning Package (PHPP), available at