Extruded polystyrene boards and glass wool batts are popular choices in insulation for homes.

Each insulation material has its own benefits; however, between the two choices, extruded polystyrene boards definitely score higher on various parameters such as ease of installation, water resistance and odourless properties.


Glass wool batts are made from recycled glass, sand and various other materials, brought together with a binding agent. The raw materials are melted at high temperatures and then woven into fibres that can then be applied as loose insulation or batts.

Extruded polystyrene is made from a polystyrene polymer, and formed using an ‘extrusion’ technique, which creates the closed-cell structure and smooth surface of the XPS boards.


Glass wool batts are lightweight and easy to handle, and can be installed in ceilings and walls of domestic properties. However, this insulation material requires protective eyewear, gloves, clothing and masks to be worn during installation due to the loose nature of the particles and irritants contained in the chemicals used to make them water- and rodent-resistant.

Polystyrene boards can be installed in walls, ceilings and under floors (for homes with timber flooring) in domestic and commercial properties. However, standard construction site safety wear is more than sufficient during installation with no additional safety equipment required to be used or worn when installing XPS boards.

Water resistance

Glass wool batts should be installed dry, which means all the moisture and dampness need to be out of the wall cavities and roof spaces to make the insulation effective. Additionally, glass wool insulation should only be installed in places free of moisture and water as any exposure to wetness can cause mould and mildew to easily form and grow. Moisture can also cause the batts to ‘settle’, and will drag them down or compact them, greatly reducing their R rating and insulation effectiveness.

However, XPS boards are already compacted, making them water resistant. These boards don’t have to be pre-treated for water resistance. Also, the minimal absorption of water will prevent mould and mildew from developing, and the board will maintain its shape and insulation effectiveness.


There is a discernible odour in glass wool batts as chemicals are used to treat and bind the fibres. Batts should ideally be aired (gassed) for some time (approximately two to three weeks) before installation; once installed it is near impossible to get rid of the smell.

XPS boards are practically odourless.  

Styroboard XPS from Foamex Group is a rigid extruded polystyrene foam that provides a strong, yet lightweight and flexible insulation solution resistant to water absorption. Extruded polystyrene is ideal for wall and ceiling insulation, cool rooms and refrigeration, under concrete slabs such as car parks, and even for architectural modelling or hobby model-making.

Styroboard XPS offers higher compressive strength, R-value and moisture resistance as well as superior thermal performance to provide efficient and effective insulation.