Insulation board performs under pressure

by Darren
Insulation board performs

Hydroboard insulation can withstand moisture and compression, making it ideal for inverted roof applications.


A high-performance rigid moulded polystyrene insulator, Hydroboard is designed for applications where resistance to moisture and compression is required.

The physical properties of Hydroboard make it an ideal insulation board for under surface-bed, perimeter and cavity installations, both on new builds and refurbishments.

Inverted roof application
It is particularly suited for inverted roofs (protected membrane) application, where the insulation is laid on top of the waterproof membrane. This protects the membrane from ultraviolet (UV) degradation caused by solar radiation and the expansion and contraction that comes from summer and winter temperature cycles, which can be in excess of 40°C on some roofs.

Inverted roofs are designed with the waterproofing layer, usually a torch on bituminous membrane, beneath the insulation, after which the insulation is loose-laid, and then a geotextile filter membrane is laid on top of the insulation. The filter membrane prevents the stone chippings penetrating the insulation if walked on and keeps out dust particles, which may prevent rainwater from flowing to the outlets. The stone chippings can be walked upon for occasional maintenance, but it may be necessary to place paver slabs for regular walkways.  

Hydroboard is ideally suited for this application as it has high compressive strength and low water absorption values, due to its closed cell structure.

Physical qualities

Properties                                                                                          32D
Density (kg/m³) – tolerance +/-10%                                              32
Thermal conductivity at 10°C (W/m.K) (mean temperature)    0,032
Compressive strength (PA) – @10% deformation                    225
Tensile strength (kPa)                                                                     440
Water absorption % volume                                                           <0,9
Temperature limits                                                                           -150°C to 70°C

The board also has excellent thermal properties, which will greatly improve compliance with the relevant legislation such as SANS 10400XA and SANS 204 Energy Efficiency in Buildings.

Hydroboard is manufactured by the expanded polystyrene division of Isover Saint-Gobain and is manufactured in accordance to ISO 9001:2008 and ISO 14001:2004 Standards.

Tel: 0860 ISOVER (476837)
Website: www.isover.co.za
Download the Isover app available for android and iOS

You may also like