The Organic Garden. Allan Shepherd

open structure that would provide shelter with a minimum of materials.

      Let’s take a quick tour. Entering the garden courtyard you are immediately struck by the drop from the house to the garden. Before the structure was built the only way to get to the garden was down a set of old concrete steps. These did not sit well with the rest of the garden.

      The solution was to incorporate a new set of steps into the overall design, to take people from the house, through the stage area and down to the garden. The whole structure is made out of green oak, which means it has been used freshly cut. Green oak lasts for decades without artificial preservatives and is extremely strong. Other woods, such as hazel, become brittle within a few years and cannot be used for this sort of structure. Most manufactured and homemade sheds are made out of seasoned wood, timber that has been left to dry for at least a couple of years. Green oak has a high moisture content and dries in situ. This means it shrinks on the job so you have to allow for this process. The green oak used here was cut to order from Powys Castle and sawn locally but there are numerous suppliers around the country. The structure is held together with green oak pegs too.

      The stairs are shaped inwards at the top to create a sense of being drawn towards the rest of the structure. Standing at the bottom, it almost feels like you are climbing into a painting by Escher.

      The stage is a triumph of space saving and space enhancement. It is supported on four posts of green oak placed on four concrete pads. Because the load is borne by these four stilts there was no need to lay trenches for concrete foundations. This saved on labour, energy and materials. The stilts also freed up the space underneath the structure (for shade-loving plants, and a cool place to sit on very hot days). The structure itself is a vertical space for plants, with climbers trailing up to the roof. In a sunny, south-facing garden this is a perfect place to grow sun-loving fruits and maximise your home harvest.

      Climbing to the top of the stairs you can turn left or right. Take the right turn and you come to the stage, but let’s take a little detour first. Stroll along the boardwalk under the clematis bower a moment and you’ll come to a small handmade wooden door. Open it and you enter the children’s playroom – a magical little space with a unique view of the garden through a square window. It’s made using a green oak frame and topped and sided with oak shingles cut by English company Carpenter Oak. To ensure

       Ethical choice: the benefits of green oak

      Green oak is used in ecological building not only because of its strength but also because it is a home-grown resource. Oak woodlands are a natural feature of the British countryside and provide valuable habitats for wildlife. A single oak tree can host hundreds of different species of wildlife and the loss or decline of many species in Britain can be directly linked to the loss of oak woodland. Oak woodland can be managed sustainably so that any trees felled are replaced by new trees. Oak has been an undervalued resource in the modern age because of the availability of man-made resources for building. By using green oak you can help to provide an economic reason for keeping old woodlands alive, protecting them from the bulldozer. Of course, there is a balance to be struck with the use of woodland resources – demand for oak should not be so great that it encourages unsustainable practices. Green oak is not the only timber that can be used to make sheds and other garden structures. Larch is often used for garden construction, and this is grown widely in the UK. Other woods suitable for heavy construction include beech, pine and Douglas fir. These are conventionally grown in plantations, which are less valuable habitats for wildlife. Whichever wood you choose to use for your shed look for the FSC symbol and, whenever you can, buy from local woodlands or plantations.

      complete protection from the rain, a single layer of breathable waterproof membrane has been placed beneath the shingles.

      Leave the room and go back along the boardwalk and you come to the stage. This is topped by an amazing parabolic curved roof, an inspiring twist of a roof that really makes you feel as if you’re in a unique space. The stage is all green oak, apart from the balustrades, which are made out of locally cut hazel with the bark stripped off to make them last longer. The balustrades are fitted in a pegged frame. The pegs can be removed, the frame dropped and the hazels replaced every ten years before they begin to rot. The green oak will not rot. It does not need weather-proofing with a chemical treatment, lacquer or paint, which is not the case with the kind of softwoods normally used in manufactured sheds (another environmental saving).

      The frame for the stage was made flat on the ground and raised with block and tackle, just like the famous barn-raising scene in the Harrison Ford movie Witness, except without the costumes. Jenny and Mehdi’s friends came to help, pulling the frame up by hand and inching it into place. A frame-raising is a real cause for celebration, a staging post in the building process. It’s a joy you just don’t get with concrete blocks.

      Planting the roof

      Leave the stage through the far entrance, head towards the house, turn round 360 degrees and look back. This should be your first glimpse of the amazing roof garden that tops the whole structure. Rolling along the twisted roof like the sea, plants rise and fall on waves of soil bedded on top of a hidden waterproof membrane. On one side a cascading rosemary sits proud to the bow, drooping purple flowers over the grey oak boarding. This is a rural garden but a roof like this could grace any urban shed or house. Not only does a roof garden provide vital garden interest in otherwise drab city streets, it soaks up some of the rainfall and absorbs airborne particles, helping to prevent flooding and reduce pollution.

      And there we have it. A multi-functional covered space that combines all the elements you would expect to find in a handcrafted organic shed. It’s made from a renewable resource cut locally, constructed with a minimum of ‘unnatural’ materials (a few stainless steel screws and ringlets, concrete pads and waterproof membranes). The structure fits the space perfectly, drawing the two levels of the house and the courtyard together while creating new garden space on the roof and around the frame. And finally, the clients’ brief has been met: great views to the sea, a home office with electricity and broadband, an adaptable social space and a secret little room for the grandchildren.

       Ethical choice: straw bales and other natural building materials

      Straw bales are an agricultural by-product, the left-over stalks from the grain harvest. Bound together into square bales they form a tight building block. These are assembled in a brick pattern and staked together with connecting hazel rods to make a wall. They are then rendered with a lime plaster to keep the straw protected from the weather and attack by rodents. Interest in straw bale building has grown as the search for more sustainable building materials has widened. Other natural materials of interest to the eco-builder are cob, rammed earth and stone. In low-rise buildings all are a viable alternative to concrete, which uses vast amounts of energy to produce and is generally less pleasant to work with. CAT’s website has a wide range of publications on all these styles of building (see www.cat.org.uk) and its courses department runs several natural building courses throughout the year. These include Timber Frame Self Build, Straw Bale Building, Cob Building, Building with Earth, and Natural Rendering – Clay Plaster. If you want to make your shed out of recycled pallets, check out www.summerville-novascotia.com/PalletWoodShed for a pictorial record and explanations of the building process. And it costs less than $100 (around £54). Also check out Kevin Beale’s factsheet from CAT, ‘How to Build With Straw Bales’, and www.strawbalebuildingassociation.org.uk.

      Other ecological considerations

      Jenny and Mehdi’s structure is very much designed for summer use. If you want an all-year-round space, you need to think of your shed more like a miniature version of your house. Eco-homes use a range of techniques to make the most of natural heating and power sources and you can mimic these for your micro-house. Passive solar heating, the process of bringing more heat from the sun into a building, is a must for reducing winter fuel bills. At a basic level you can achieve it by giving your shed space large, south-facing windows, accompanied by smaller windows to