luscious green roof on a garden shed

DIY Green Roof Guide

The online resource for building small scale green roofs on garden sheds, garages, house extensions and other small construction or retrofitting projects

a green roof on a new house extension

New Builds

A step by step guide to creating a SAFE and LEAK FREE green roof on a new small scale construction project. Learn from the vastly experienced authors how to accomplish it yourself or provide guidance to your contractors

a small green roof on an electrical substation


Even the smallest of roof spaces can provide a small haven of beauty and a wildlife oasis. The retrofitting section advice can be used on garden sheds, cycle & bin shelters, the fundamentals remain the same!

edge details of a garden shed green roof


From suggested screw sizes through edge details to drainage suggestions, John & Dusty take you through the process using text, photos, illustrations and videos

edge details of a garden shed green roof

Planting Ideas

Plant suggestions focussed on native species that can provide the maximum biodiversity. Separate lists for the UK, Eastern USA & Canada, Mid-West USA

The Roof Must Not Leak: Green Roof Waterproofing Layer

Although this may seem obvious but we know of cases where people thought they could cut corners in this area and unfortunately suffered water leaks within a very short time.

Don’t scrimp on the waterproofing layer

Sadly, it currently seems impossible to avoid using a petroleum based product for a green roof waterproofing layer. If we could we would recommend one but to date we have no knowledge of any that is available. In waterproofing terms EDPM’s are generally considered the most environmentally friendly.

Our experience over the years is that a lightweight pondliner is sufficient for a small scale green roof. The Walter Segal method of waterproofing for self-build uses a pond-liner material. This is the method John used on his first green roof on his own house.

Jon Broome, who has built a number of houses using this method, including on his own house Shaw’s Cottage, where our good friend and colleague Gary Grant designed the roof.

The advantages of a pond liner for small scale builds are:

  • The pipe sleeve [outlet sleeve] for internal drainage can be supplied pre welded to your liner in the position you specify, saving work and detailing for the  builder.
  • Another advantage is also that the complete liner can be fabricated off site and delivered in one piece. This means no specialist onsite work. The waterproofing is simple rolled out and ready to go.
  • A good pond liner has a very long life even when exposed to UV, meaning it will last even longer beneath a green roof.
  • It is light and flexible.

The disadvantage is:

  • Pondliner is not as puncture resistant as other membranes therefore CARE is needed.

You can always go for a superior waterproofing layer and get this installed by an approved contractor. EPDM Single-Ply Membrane is the standard alternative.

In the case of installing EPDM, you might seek to use an approved contractor. However you may have to argue that the only element you want to purchase from the supplier is the geotextile protection layer and not be swayed by any insistence that you also purchase their substrates and drainage layers in order to meet their guarantee criteria.

Green roof waterproofing layer

Learn how vital a good waterproofing layer is!

Get Started Now or Find Out More!

Gain immediate lifetime access for only £11.50 or an annual subscription of £5.50 per year. Or merely browse the public areas of the website and find out more about the whys and hows of designing and building small green roofs before you join. 

Spring 2024 Special

The first 30 new registrations for the Lifetime Membership option can get £2.50 off the usual price by using the discount code 20E3E039F7  at the checkout. That means only paying £9.00 in total to gain permanent access the full guide. So grab a discounted membership now before they all go.