Designing & Specifying a Green Roof

A green roof comprises several layers that are laid on top of the roof deck. These vary in depth according to the exact specification and type of green roof. The main layers are shown on the profile diagram below.


Structural considerations

A green roof can be installed on new buildings or retrofitted on existing ones. It is important to obtain sound advice on structural considerations as a green roof can increase loading on a roof by 85-135kg per square metre depending on substrate depth.

Slopes of over 10 degrees may need additional slope stabilisation to avoid slippage of substrate and measures to ensure the vegetation layer is secure - Lindum can supply slope stabilisation options if required.

Lindum green roofs have a depth of 105-155mm and a saturated weight of approximately 85-135kg per square metre depending on substrate depth.


Depths and Loading Weights

Material Depth Saturated Weight
Vegetation layer 25mm  25kg/m2 fully saturated
Extensive green roof substrate 75mm  75kg/m2 fully saturated
Roofdrain drainage layer 30mm 10kg/m2 fully saturated
TOTAL 130mm deep  110kg/m2 loading

* The above are only examples. For specific load weights for each vegetation mat please see the technical information sheets.

Lindum Green Roof Package

Lindum has developed a green roof package which can be installed on flat or pitched roofs (up to 30 degrees without additional irrigation).

The package consists of a choice of vegetation mat, lightweight substrate containing recycled growing medium, and Roofdrain drainage layer to sit above the waterproof membrane.


Technical Information

Lindum Green Roof technical material