Foamular extruded polystyrene from Austech External Building Products is being recommended as an effective insulation solution for green roof gardens.

An increasingly popular roofing option for concrete roofs, with many modern cities demanding a percentage of total roof space to be green, a green roof is a roof surface, flat or pitched, planted partially or completely with vegetation using a growing medium over a waterproof membrane.

Green roof gardens deliver several benefits to the home including increasing thermal mass and improving insulation; creating more stable temperatures in the building below; reducing energy demands for artificial heating and cooling; minimising noise; enhancing productive garden space and biodiversity; providing beautiful views; reducing rainwater runoff that ends up in stormwater systems; and improving air quality.

However, green garden roofs provide very low insulation from the soil and plants, especially when wet, necessitating additional insulation to be installed to achieve adequate R-values.

Foamular extruded polystyrene, a closed cell board with minimal water absorption and high R-values, is placed below the soil but above the concrete roof, creating a continuous thermal barrier.

The high compressive strength of the extruded polystyrene ensures the board is not affected by continuous pressure from foot traffic, growing medium or other loads, allowing pavers and ballast to be placed on it to provide for walkways and recreation areas within the roof garden.

Foamular extruded polystyrene offers no nutritional value to plants, animals or bacteria, eliminating degradation. With its very low water absorption potential, it can easily function even when exposed to moist growing medium and water runoff.

Austech offers Foamular extruded polystyrene in a range of compressive strengths to deal with heavy loads including vehicular traffic.