Everything you wanted to know about green roofs but were to afraid to ask


by Vicky Bhogal student on CAT’s Advanced Environmental and Energy Studies course

In February Blanche Cameron ran her module at CAT. One of the visiting lecturers was Dusty Gedge, who taught us about the benefits of green roofs.

Dusty has big plans to green London’s roofs: reducing the urban heat effect through transevaporation, helping to absorb water to prevent floods and replacing a building’s original green footprints with a living roof. As well as creating cool oases in the hot city.

Our flat roof extension in Brighton was on its last legs. Water was seeping through the cracked asphalt and beginning to stain the ceiling and walls. So it was time to do something about it. I went on a weekend course in practical green roof construction, run by Dusty. I came home with a sample corner section and an instruction manual.

I assembled my team: husband, good friends and volunteers from Brighton Permaculture Trust and ordered the butyl (pond) liner and thick felts. The construction took two weeks due to heavy rain, and cost about half the price of a conventional flat roof.

Help and advice on green roofs is available from CAT’s free information service. You can speak to someone about whether a green roof is right for you, download our fact sheets and find out where to get more information

We chose to replace the existing roof with a green roof because it looks delightful and we wanted to replace the grass removed when the extension was built We also wanted to encourage insect life into the garden. We used a substrate of varying depths and types, including lots of chalk, to recreate areas of local chalk downland, next to more compost rich, fertile areas. I transplanted lots of seedlings from our garden planted wildflower seeds.

At first, friends joked that we’d made an aerial weed patch, but during the summer the roof changed into a waist high poppy and wild flower field filled with bees and other insects. We have even been visited by the rare blue fritillary butterfly. Because it’s a living roof, it’s full of surprises; constantly changing and evolving. As we move into autumn, the wild flowers are dying back and there is a new growth of clover and snap dragons. I’m looking forward to watching the changes and seeing which plants grow over the next year.

I loved my time at CAT and feel blessed to have studied there. It has been a life changing experience. My formal training was in Art but the open access policy of the MSc meant that I was able to discover my hidden social scientist. I have developed strong friendships with students and we have also learnt a lot from each other. A group of us are working on setting up a local training and education centre in renewables and natural building techniques; with the goal of empowering and enabling others through sharing what we’ve learnt at CAT.

tea chest turf roof at centre for alternative technology.JPG
A turf roof at CAT

World Green Building week. Tour of CAT’s WISE building

by Caroline Alsop

According to a report by the European JRC PV Status Report 2011, Solar PV is now the fastest growing industry in the world.

With Solar PV production more than doubling in 2010 there’s significant evidence that green building techniques and methodologies are being used more widely in today’s building sector. In the next revision of building regulations in 2013 planning and development laws are expected to take a further positive step towards increased environmental sustainability and energy efficiency. From here on in, the demand for awareness in green building methodologies is likely to expand at a fast pace. However there is still plenty more to achieve.

The UKGBC (UK Green Building Council) have identified that ‘The Built Environment has a huge impact on our daily lives, our society and our natural world. Globally it accounts for 40-50% of natural resource use, 20% of water use, 30-40% or energy use and around a third of CO2 emissions.’ To address these worrying statistics, since 2007 the UKGBC have been on a mission to increase awareness about sustainability in our built environment. To help achieve this, each year they host ‘Green Building Week’ an event encouraging their members to talk about sustainability in their built environment.

This year, they’re using the event to ask the question ‘What does sustainability mean in relation to the built environment?’ Us folk at CAT thought the best way to answer this question was to host a tour of our 2011 RIBA awarded WISE building (Wales Institute of Sustainable Education), showcasing our unique vision of sustainability and the built environment. On Tuesday architect Pat Borer took a group of local architects and CAT visitors around WISE.

After the tour, CAT visitor, Simon Shelley commented ‘that was inspiring and fascinating. I have been told about building methods and materials I didn’t even know existed!’

For those who were unable to attend, here’s what sustainable design and construction means to our built environment.

Nestled in the scenic hills of Snowdonia WISE is the true embodiment of sustainable design and renewable technology. Sensitively constructed out of low embodied energy materials such as hemp and lime, rammed earth and sustainably sourced timber. It’s been thoughtfully designed for low energy consumption use. Contributions come from on-site renewable electricity sources such as solar PV, hydro and wind turbines, and an impressive array of solar thermal collectors contribute to the domestic hot water needs.

Green Building Week has been an excellent opportunity for us at CAT to raise awareness about our sustainable design and construction practices. Moving forward, with Green Building Week in mind, CAT will continue to provide the confidence, training and capabilities which will inspire individuals to construct their physical surroundings using local and natural resources in a thoughtful and realistic capacity.

WISE - Tim Soar photographs

Podcast: People, buildings, energy and sustainability. Nick Baker, Martin Centre, University of Cambridge

You can stream this podcast here or

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This lecture is part on the MSc Architecture: Advanced Environmental and Energy Studies course.

Nick Baker from The Martin Centre in Cambridge has spent most of his professional life working in building physics as a teacher, researcher, and consultant. He is also co-author of ‘Daylight Design of Buildings: A handbook for Architects and Engineers’

More podcasts

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Experience: Timber Frame Self-Build, an empowering journey in sustainable building skills

Last year I spent six-months volunteering in the CAT media department. Volunteers are invited to take part in two courses of their choice free of charge. Determined to build my own house one day, and to learn the skills I need to renovate my existing home, I chose Timber Frame Self-Build.

Attending the course were people from all walks of life, including self-builders and design & technology teachers wanting to improve their practical skills to pass on to their students. There was a nice mix of men and women, both younger and older, and plenty of people who hadn’t used a saw or drill before as well as those who had.

We started by discussing why we were all on the course. The tutors also introduced themselves and outlined self-build projects they had been involved in. It was great to learn that Pat Borer had designed WISE, the building we had our seminars and bedrooms in, and more that it was timber framed and built using locally sourced timber – local being only 500m down the road – and skills similar to those we were about to learn.

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Book on either Timber Frame Self-Build or Eco Building from New during Green Building Week and enter the chance to win a £50 voucher or free day course.
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From then on in it got more intense as the practicals began, making for a fast but fun learning experience. Tutors Duncan Roberts, Pat Borer and Geoff Stowe were great at making sure each team worked together effectively and gave everyone a chance to ‘have a go’. The diverse range of skills in the group meant that there was a lot of peer teaching too, great for overall team spirit and getting things done.

I was totally amazed at the outcome of the course. We constructed two timber frame structures – one using a post and beam method and the other using stud walls. It was amazing how much we could achieve in just five days.

During the evening seminars we also looked at self-build design principles, taking in the work of architect Walter Segal by looking at examples of his designs on the CAT site.

The course was exactly what I was looking for. I was so keen and motivated after the course that the following weekend I built a new wood shed for my garden, putting into practice the skills I had learnt on the course. Both teams worked so well together we stayed in touch after the course – we’re waiting for the first of us to embark on their own self-build project so we can all go and lend a hand.

Course participants lifting timber frame

7 green building blogs you should be reading


Green Home Building and Sustainable Architecture
Lengthy, in depth, well written posts reviewing recent books and reports. Kelly Hart is also a consultant on various sustainable building projects and draws on his own experience on the blog. The blog is focused on US projects, books and reports.

Slick, colourful and constantly updated. This is a blog for keeping pace with new and innovative design projects, rather than a place to read about technical aspects of sustainable building.

Green Building Elements
Green Building Elements covers news from the world of green building, art and architecture. Very hi-tech, with a focus on how sustainable building relates to global issues such as peak oil and climate change.

Sustainable Construction Blog
Technical and construction focused. If you’re interested in sustainability (or lack thereof) in large scale construction this is an interesting place to start.

Sustainable Cities
Run by Danish Architecture Centre, the blog covers case studies and stories from all over the world. A good place to look if you want a global perspective on sustainable building. The case studies section is very good, covering projects in much more depth than many other blogs.

Architects’ Journal Footprint blog
The AJ’s contribution to green architecture blogging is impressive. Hattie Hartman writes a mixture of quick updates and well researched reviews. The blog obviously focuses on green architecture and design, but often ventures into wider global issues and broader commentary on construction and energy.

The Guardian: greenbuilding blog
This is where all the Guardian’s content on green building is drawn together. It’s a mix of articles and features written mainly by the Guardian’s environment team, but also including pieces by their science and society commentators. This is also a good place to keep up to speed with policy issues around planning.

WISE 5 Feb 2010

Green Building week at CAT and our students’ adventurous architecture project in the woods

In preparation for Green Building week (19th- 23rd September) Suzanne Burlton reports on some of the splendid sustainable architecture built by our Graduate School students

The impact of buildings is proportionally very large, accounting for 30-40% of energy use and a third of CO2 emissions. Green Building Week promotes sustainable building techniques which will reduce our impact on nature while also aiming to create buildings which provide social benefits. This involves design, materials and construction techniques, and here at CAT we don’t think these can be developed in isolation.

The late, great Arthur Erickson said that “Architecture doesn’t come from theory. You don’t think your way through a building.” Therefore, while a week in the design studio forms an important part of CAT’s ProfDip Architecture Summer School, it is the week spent building in the woods which often most transforms the way the students view their role in the overall process of design and construction.

One group designed a birdhide to be installed in the Coed Gwern woodland on the other side of the Dyfi Valley. The group were inspired by the environment to design a curving timber structure made up of slats which allows maximum visibility of birds while at the same time echoing the surrounding woodland in its materials and organic shape.

The idea originated two months earlier during a design charrette, and out of the five designs which resulted from the intense period of work, the one by student Bryn Hallett was chosen. The materials were ordered and prepared in order for work to begin in late August.

In the words of one student, good design aims to confront and dissect “the cultural, geographical and environmental uniqueness” of the site to create an “architecturally rich” intervention. This project was radically local, in line with the aims of Green Building Week to use architecture to restore and promote communities. The trees were felled in the area of the actual building site and sawn to the required dimensions in the Esgair Timber Company sawmill about half a mile up the forest track. Wood is a renewable building material which locks in carbon during its growth cycle and naturally filters the air.

Out in the woods there is little opportunity to use power tools due to the unavailability of grid connections, so the students had to be innovative in their constructions techniques. This gave them a real appreciation of traditional building techniques and how much modern construction relies on increasingly scarce energy resources, encouraging them to develop new ways of putting together their structure.

CAT’s ProfDip Architecture is a Part II course designed for those who wish to take Part III elsewhere in order to eventually register as practicing architects. We aim to be a centre of exemplary practice, training those who will design the buildings of the future to enable them to incorporate sustainable methods and materials for the benefit of the local community and the wider environmental context.

We welcome the opportunity to take part in Green Building Week in order to promote our shared aims of transforming the architecture and construction industries into ones which incorporate sustainability issues into their work at a fundamental level.