Blog from the Centre for Alternative Technology
Sustainability into practice
Continue reading “The nature of CAT – an interview with the woodland team”
The shift to zero carbon is one of the most exciting opportunities in human history. It offers huge benefits in better housing, affordable and accessible transport, reduced obesity, improved health, cleaner air and more jobs.
Everyone is talking about rewilding at the moment.
The debate around rewilding is shaking up the conservation sector – and public interest is huge – with a growing movement of people advocating the restoration of our degraded ecosystems.
Continue reading “Brand new practical course at CAT – Introduction to Rewilding”
Imagine a world where we have broken our ties with fossil fuels… Our towns and cities are awash with innovative practical projects that are rebuilding our relationship with food, energy, transport and buildings, openly supported by the wider economic and political systems. Such innovation has unleashed all kinds of co-benefits, from cleaner air to better diets, more jobs and income arising across the local area.
Continue reading “Carbon lock-in – 10 ways to break the cycle”
Continue reading “Worldviews and values – inspiring the shift to zero carbon”
Transforming our transport system from one that is highly polluting and heavily reliant on fossil fuels into one that is clean, green, reliable and affordable is a challenge, but it can be done. Here is a selection of ideas on how we can create a better transport system that’s not only healthier for us all, but is compatible with a zero carbon future.
Continue reading “Creating a zero carbon transport system”
Reforming our high carbon, low quality food system will be a complex challenge, but it is possible. Here are a selection of ideas on how we can create a better food system that’s not only healthier for us all, but is compatible with a zero carbon future.
Continue reading “A food system fit for a zero carbon future”
CAT’s Architecture Professional Diploma students celebrate the end of their studies with a private view of their work and a party at CAT on 20th January.
This unique event invites industry VIPs, students, local people and friends of CAT to view the final projects of these up-and-coming architects after 18 months of intensive study. Transforming study rooms into exhibition spaces their inspirational designs and models will be available to view with the students themselves on-hand to talk guests through their visions. This will be a unique insight into the ideas of the architects of our future. Continue reading “Celebrate with CAT’s architects of the future”
Want to refurbish your home in a sustainable way? With over 25 years’ experience, including as tutor on CAT’s Eco Refurbishment course, Nick Parsons has some great advice – here are his top tips.
1. Make it air-tight.
Stop unintentional ventilation (this involves designating an air-tightness layer – and sticking to it!) and design in sufficient intentional ventilation. For a whole-house retrofit this will almost certainly be whole-house mechanical ventilation with heat recovery (MVHR), but for incremental retrofits, or those with less stringent air-tightness targets, passive ventilation may suffice.
2. Insulate, insulate, insulate!
Don’t automatically believe that Building Regulations standards of insulation are enough. They aren’t bad, but in many cases we should be aiming for far better. If you have the space – and the money – Passive House levels of insulation (U values of 0.15W/m2K or less) and air-tightness (less than one air change per hour for the refurbishment EnerPHit standard) can dramatically reduce your heating requirements and massively improve comfort.
3. Insulate externally! (Unless you can’t…)
External insulation of solid walls, if detailed properly, puts the entire building fabric inside a warm ‘tea-cosy’. But it does make your house look different.
4. Risk-manage your insulation
If you have to insulate your solid walls – or sometimes even add insulation to your cavity walls – internally, excellent detailing is critical. Insulating walls internally makes the room warmer but makes the walls themselves colder and more at risk of interstitial condensation – condensation within the new thickness of the wall, behind the insulation. This can rot joist ends and other embedded timbers, and maybe grow mould. Cold walls may also suffer from deterioration of the masonry due to frost damage.
If you insulate internally, make the whole process a documented risk management exercise – identify the risks, identify control measures and document how you will implement them. In certain circumstances, consider embedding sensors and monitoring equipment in hidden timbers so that you can know if moisture levels become critical. The expense may be off-putting, but it will be a great deal less than the remedial works if you have inadvertently shortened the life of your house by doing what you thought was the ‘right thing’.
In general the use of ‘breathable’ (water-vapour-permeable) insulants such as wood-fibre or cork may reduce risks, but very careful detailing is still required.
Greater risks exist with non-breathable insulants, but if they are installed with extreme care, the risks may be capable of being ‘managed’ and minimised. If you are installing them yourself, take advice from someone with a lot of experience. If someone else is installing them for you, are they experienced with such boards? Do they fully understand interstitial condensation and vapour control layers (VCLs)? Have they read the manufacturer’s installation instructions?
5. …and consider its environmental impact
Materials such as plastic insulation – made from crude oil – are high in embodied energy (the energy, including transport, used to get the product from raw material to the merchant’s shelf), but look at the units used. If the measure is weight, a heavy bit of ‘green’ insulation may be higher in embodied energy than a much lighter piece of ‘non-green’ insulation.
You may in any case wish to avoid wherever possible materials made from petrochemicals.
But ‘environment’ may mean more than ‘the world in general’. What about your immediate living environment? You may feel better in a room lined with vapour-permeable, moisture-buffering wood-fibre than in a room lined with petrochemical-based insulation.
6. Minimise thermal bridging
You may believe – perhaps because your builder or consultant told you – that having low (good) U values guarantees good performance but thermal performance may be let down by weak-points in the insulation layer. Typically this would be where partition or party walls interrupt the insulation layer, where walls turn into windows or doors, or where internal insulation has to be thinner to accommodate fixtures or fittings. In practice, your U value may not be as low as you believed it to be.
The picture on the left shows: on the left, a wall prepared for insulation to ‘return’ on to internal wall to cloak the thermal bridge; in the middle, Pavadentro wood-fibre board prior to plastering; and on the right an existing brick wall with a lime ‘parge coat’ (air-tightness layer) to reduce air-leakage through voids in the brick wall.
7. Minimise thermal by-pass
Thermal by-pass, or ‘wind-wash’, occurs when cold air is allowed to get to the ‘warm side’ of the insulation. This can best be explained in two scenarios:
The first is a loft-conversion. The eaves areas are cold voids. The stud walls to the room (which are built off the floorboards) have been insulated to a good standard but there is only 100mm of insulation between the 150mm floor joists.
The ventilation air which enters at the eaves vents (a good ‘howling gale’ to keep all the timbers healthy) can blow directly under the floor of the heated bedroom, providing instant cooling!
Small pieces of plywood or similar board, sealed at all perimeters, placed between the joists at the edge of the floor on both sides of the bedroom will cure the problem. ‘Plugs’ of quilt insulation placed in the gaps will not do such a good job (as quilt insulation is generally air-permeable), but will be better than nothing. Once these gaps have been sealed, the insulation should in any case be increased to approximately 300mm.
The second scenario involves insulation to the sloping ceilings above an attic bedroom, carried out, as the law requires, by roofing contractors when re-roofing the house.
The house was sold and the new owner decided to remove all the attic ceilings. All but about six of the sheets of insulation fell out from between the rafters. What this tells us is that, while the insulation was in place, the cold air in the ventilation gap between the insulation and the slates was able to migrate to the warm side of the insulation, rendering the insulation almost useless.
8. Plan to do it all!
Many insulation plans are carried out incrementally, perhaps as other work is required, or when a room needs comprehensive re-decoration or (externally) when the cost of re-pointing an elevation can be avoided and put towards the cost of externally insulating that elevation.
When planning your works, ideally plan to do the whole house, even if you know it is going to take you 10 years to achieve it. I’m 29 years in and starting to re-do the internal insulation using better materials and methods than were available in 1987! Plan how your individual works are going to ‘knit together’ so as to limit thermal bridges, where condensation and mould may otherwise occur.
Above all, you don’t want your works – undertaken with the best of intentions – ultimately to shorten the life of your house.
About the author
Nick Parsons has worked in energy-efficient and sustainable building and renewable energy for over 25 years. He provides consultancy and project management services to individuals, small businesses and community organisations and is a regular tutor at CAT and elsewhere. See www.sustainablebuilding.org.uk for details.
CAT courses
The next eco-refurbishment course with Nick takes place from 4th to 7th November. For more information and to book, please visit http://courses.cat.org.uk/ or call us on 01654 704966.
A figure emerges from the undergrowth, with mud-covered face and a wild look in the eyes. Is it a fox? A badger? A wildcat? No… it’s a participant on CAT’s nature connection course! Kara Moses reports…
Traditionally, people have had an intimate, even sacred, relationship with nature, recognising and honouring our dependency on the natural world for our very survival – indeed understanding that we are the natural world, not separate from it. As Thich Nhat Hanh says, “The Earth is not the environment. The Earth is us. Everything depends on whether we have this insight or not.”
In more recent times in our history, we have come to see ourselves as somehow separate from nature. We have created socio-economic systems that don’t honour our place within the web of life; nature is treated as a resource to be used for human profit and pleasure, as a waste dump to discard the spoils of consumerism, or as an adventure playground.
This separation works to devastating effect, causing not only ecological – even civilisation – collapse, but exploitation of people, growing inequality and greater suffering in our world. There is a clear need for a deep shift in perspective individually and collectively, towards a life-affirming worldview and social structures that honour our Earthly home.
Why connect with nature?
The emerging field of ecopsychology is discovering that it is not only our relationships with our family and society that fundamentally affect our well-being and inform patterns of behaviour, but also our relationship with nature. To begin to heal the broken relationship with the natural world and each other we must reclaim meaningful connection that brings us into a deep, embodied sense of participating in a cosmos full of wisdom, value and meaning.
Rekindling this sacred connection to the earth and all its inhabitants has the potential to heal the sickness of our times, transforming social relationships. A growing body of research shows that increased time in nature brings greater happiness, better mental and physical health and emotional resilience. Connecting to nature supports us to connect more deeply with our selves and others.
Deep solidarity
Research also shows that feeling more connected to nature also leads to an acting as well. Through recognising that we are in fact part of it, people who feel more connected to nature are more likely to display ‘pro-environmental behaviour’. They begin to see that we are not defending nature – we are nature defending itself.
Here at CAT we’ve recently added nature connection to our short course programme. The first one ran in late summer, and went down a treat. Through play, mindfulness and practical nature connection exercises, we developed our powers of observation and saw all sorts of natural delights we would normally miss, with a renewed sense of awe and understanding.
Together we developed skills to interpret the natural world, such as tracking, understanding bird language and the body language of trees. We played games to help increase our sphere of awareness and reduce our sphere of disturbance to see and understand more of our wild cousins, and explored the theories of deep ecology and radical ecology. And we spent lots of time outdoors in the beautiful surroundings of CAT – we were a pretty feral bunch by the end!
More feral less fearful
I’m glad to say that the participants have been putting their experience and learning into practise in their daily lives, enjoying more time out in nature cultivating meaningful connections. One participant said a week after the course: “I’m listening to the birds with a new sense of understanding and joy.”
Some have made even bigger life changes: “I spoke about wanting to make a healthier more sustainable life and career change. It’s always a nerve wracking thing to leap from what you know into what you don’t, but the course inspired me to take this step and run nature connection walks myself. It’s great to connect with people over a subject that is intrinsically meaningful. More feral less fearful!”
After the success of this course, we’re offering more weekends in November 2016 and in April and July 2017 at affordable rates from £35/day. The last one sold out so book here soon if you too want to rewild your self and become more feral!
Kara Moses leads nature connection courses at CAT and independently. She also takes care of CAT’s natural water treatment systems and is a freelance journalist, Forest School leader and grassroots trainer.