Green Roof Design Tips

The living roof is also known as a green roof, and as the name suggests, has a visible top layer that consists of plant medium. There are several ways a living roof can be crowned, depending on your taste, the purpose of the green roof and its weight-bearing capacity.

Permaroof’s green roof division is passionate about making the UK greener, one roof at a time, and understands the full value of the green roof in terms of:

• Aesthetic value
• Surface water management
• Sound insulation
• Creating an environmental habitat for urban wildlife
• Energy efficiency

We’ve got a few tips to help you decide on the design of your living roof.

Choose a good quality EPDM membrane for the base layer

This is perhaps one of the most valuable pieces of advice we can give you. The base layer has to provide waterproofing across the entire project and will be adhered directly onto the roof deck. EPDM membrane is perfect for a long-term living roof, providing 100% waterproofing with a life expectancy of more than 50 years. Firestone Rubbercover systems are installed in a single sheet, eliminating the vulnerabilities caused by joined membranes.

Use insulation widely across the living roof

Make sure your base waterproofing membrane is completely protected from the gravel and any sharp stones that may be used in the following drainage layers. Although EPDM does not damage easily, adequate protection should be given to avoid puncturing the membrane. Cover the entire surface area with suitable insulation, such as:

• Geotextile fleece
• Rot-resistant cushioning
• Old blankets – these should be thickly layered

Insulating your green roof effectively can also contribute significantly to making the home more energy-efficient.

Consider maintenance aspects during the green roof design process

There are three types of green roof design – extensive, semi-intensive and intensive. Extensive green roofing is the low-maintenance option and is often planted with mediums that are mostly self-sustaining and hardy against most weather conditions. The most successful plants for extensive green roofs are sedum, rough grasses or moss. Semi-intensive design is often used in roofing that can be used and walked upon, such as roof terraces. Paths with planting that can be lightly maintained are ideal. Intensive green roofing is often the most weight-bearing option, so advice from a surveyor or architect is advised if you’ve been considering this type of design to make sure your current roof can support the additional weight.

Intensive green roofing offers as many design ideas as a garden. The use of trees and shrubs is seen on intensive living roofs, in addition to garden furniture, patio areas, vegetable and flower beds. The sky is the limit to design with an intensive roof.

Add interest around the edges

Dull, yet necessary drainage channels can be made much more attractive around the edges of a green roof if filled with stones of differing sizes. A cheaper, rough gravel layer on the bottom can be disguised with larger pebbles and rocks arranged to be seen from the ground. Adding large stones or even a water feature can make a huge difference and break up the effect of a moss or grass roof.

Think carefully about planting and how your green roof appears from the ground. If you have high roofs, then planting around the edges of a living roof with plants designed to grow long and overhang can look stunning.

It is a good idea to really spend some time on the design of your living roof during the planning stages. Making mistakes can prove costly in green roofing, and the worst can mean removing several layers of heavy planting medium, soil and gravel and starting again.

Talk to Permaroof’s green roof division on 01773 608 839 to discuss your thoughts about your living roof project, or visit the green roof page now to download a brochure and find out more.

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