extensive green roof on a small 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 bike shelter

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

poppy and harebell as green roof plants

Plant Lists

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

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!

gabion edge details of a 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

Pre-Development hydrology, what’s that?

by | Mar 30, 2015

Pre-development hydrology? Well it took a visit from an expert from Colorado to explain this term to John and Dusty. Not that they hadn’t been involved with the idea – just that we refer to the issue as ‘humps and bumps’! Or topographic variety to be technical.

Professional Design Guide to Green Roofs

This is the video that always makes me laugh and I know it makes Karla Dakin giggle too. Karla visited the UK a couple of years ago to speak at the US Embassy about her great book – The Professional Design Guide to Green Roofs – in which John and Dusty feature amongst other stars of the green roof world. Furthermore Karla will also speaking at this years 2015 Virtual Green Roof and Wall Summit. She’ll be focussing on how to design green roofs in high and dry Colorado. A challenge when you consider the amount of precipitation they get in Denver.

Pre Development hydrology on a green roof

Denver Botanical Guidelines

Soon we will get Karla to make us a planting list for the mid west to put on the guide. Can’t wait as they use cactuses and other desert plants. Now that is cool.

Pre Development hydrology

So wandering across the roofs at Hilldrop admiring our ‘humps and bumps’ Karla says – ‘This is taking the whole idea of Pre-Development hydrology to a new level’. Well that is compliment but we were stumped for words. Pre-Development hydrology. what’s that?

Of course with a little explanation it was all about how we like to drain our roofs using natural features – dry river beds – which create ‘humps and bumps’. Here in the UK we are still waiting on the Government to push through SUDS guidance. However it is unlikely it will go quite as far as they do in North America and countries like Switzerland and Germany. There they ask developers to try to landscape developments to mimic the drainage of the site prior to development.

Green roofs are part of that story even the small ones that online guide describes. So when you build your small scale green roof you can help get back a Pre-Development hydrology – or so Karla Dakin reckons.