Text: Sean Woods. Article from December 2011 issue of Popular Mechanics Magazine.
One man builds an eco-friendly home on a budget.
Building a conventional home using bricks and mortar is all very well – as long as you don’t mind selling your soul to your bank manager for 20 years and living in an unimaginative rectangular box, that is. For Simon Dale, this utterly conventional approach to domesticity held little appeal. Not cash-flush enough to raise a bond, and wanting his family to live close to Nature, he decided to build his own eco-friendly home. He accomplished this feat in just four months for less than R40 000.
The Dale family’s quirky dwelling, situated in the Welsh countryside, conjures up images of The Shire and that fictional abode of Bilbo Baggins, made famous by JRR Tolkien in his fantasy novels The Hobbit and The Lord of the Rings.
But, as outlandish as it may seem to those unfamiliar with environmentally friendly building methods, make no mistake: the rationale behind its design and construction methodology is based firmly in reality.
Here’s why. The whole point of eco-friendly construction is to use as much of the available natural material in the vicinity as possible. And all Dale has done is incorporate what his corner of rural Wales provides – namely wood, stone, straw, mud and, oh yes, turf. Lime plaster, a breathable and greener alternative to cement, coats the interior and exterior walls. Inert black plastic sheeting was used in the foundation and roof to prevent water ingress. The rest – wooden flooring, windows, wood burner, plumbing, wiring, fittings and the like – he simply scrounged. “Anything you could possibly want is in a rubbish pile somewhere,” he says.
The building is one part of a low-impact or permaculture approach to life, Dale explains. “This sort of life is about living in harmony with both the natural world and ourselves, doing things simply and using appropriate levels of technology. We built this place to house our family while we worked in the surrounding woodland doing ecological woodland management and setting up a forest garden, things that would have been impossible had we needed to pay a regular rent or mortgage.”
That he went for a decidedly unconventional, hobbit-like design is his prerogative.
So, working from this environmentally friendly building premise, it stands to reason that, if you live somewhere like the Free State where there’s plenty of grassland, straw bale construction would make perfect sense. If, on the other hand, there’s plenty of clay in the area, cob construction would be ideal. And if you live in or near a pine plantation, vertical log construction would be a no-brainer.
Heck, if you’re lucky enough to have some land in the Amatola Forest near Hogsback in the Eastern Cape (where legend has it Tolkien got his inspiration for The Hobbit and The Lord of the Rings), you could most probably even go for Dale’s exact design.
Getting started
Once Dale had secured a piece of land from a friendly farmer, he, his father-in-law and a few visiting friends got down to business. The plan was to dig into the hillside to create as low a visual impact as possible. Because it would take too much manual labour to achieve this by themselves, they borrowed a knackered old digger the landowner already had on site. This enabled them to excavate the area to the required depth so they could incorporate a mezzanine floor. Once the hole was completed and the ground levelled, they used the excavated stone and mud to construct dry-stone foundation and retaining walls.
About 30 round oak posts between 12 and 25 cm in diameter were sourced from the surrounding woodland to construct the oval frame. As the trees were deemed too spindly for conventional use (except for firewood, fencing or mulching into wood-chips), they were felled as part of the ongoing programme of woodland thinning to allow selected trees space to grow to maturity. Says Dale: “Basically, all this required was a chainsaw, a few able-bodied helpers and plenty of heavy lifting.”
Reciprocally speaking
Once the vertical posts had been secured in the ground, a ring of horizontal logs was attached to the posts using open mortise and tenon joints to create the much-needed roof plate, and work on the reciprocal roof could begin.
Reciprocal roofs are ideally suited to round wood construction: they require minimum woodworking and are structurally uncomplicated (because they don’t push outwards on the walls, they don’t require tie beams). “Although constructing a reciprocal roof is relatively easy, getting your head around the technique can be a bit tricky,” Dale warns. “I recommend having a go with a few small sticks before trying the real thing.”
To start off with, you temporarily prop up the first rafter a little off the centre point of the essentially conical roof. When you’re happy, lay the second rafter on top. Then lay the third and so on. The distance between intersections or crossing points can be checked, by keeping the points where the rafters touch all in a level plane as you work around. “The rafters should be fixed temporarily as you go,” advises Dale. “Nailing something about a metre long between the rafter and the previous one a little way down from the top seems best to me.”
Then, when you get to the last rafter, you should find just enough of a gap to squeeze it in. If it’s not quite right, a quick jiggle of the last few rafters should adjust the size of the gap. Once all the rafters are in place, you take the prop out from under the first. “This is the exciting bit. Hopefully you’ll hear a creak and the inner ring drops by a few centimetres,” Dale says.
“However, I would strongly recommend doing this with a good rope tied around the outside of the inner ring until the final fixing is complete. And, though it barely needs it, fixing the rafters together is recommended. I used 2,5 cm diameter wooden pegs although rebar, nail tape or 15 cm nails are good alternatives.”
Finishing off the roof involved applying a series of layers to achieve insulation, waterproofing and low visual impact with little cash. First, cotton dustsheets were laid over the multitude of split logs that had been attached in a symmetrical pattern to the rafters. Next, whole straw bales were packed on top, followed by three layers of plastic membrane. Earth from the original excavation was packed on top of the plastic and, finally, tufts of grass were planted into the soil to make everything, well, nice and green. Finally, a skylight was placed over the reciprocal roof s central opening to let in plenty of natural light.
Bring on the straw
Straw bale construction is nothing new; after all it’s been around since the 1800s. However, don’t let that detract from its ability to create superbly energy-efficient buildings. It’s also incredibly easy, cheap and fun to build with the stuff. “Straw is a great insulator,” says Dale “It gives heat savings of up to 75 per cent compared with a conventional modern house. Straw bale walls have excellent load-bearing capacity and are quite suitable for double-storey houses fitted with all the mod-cons.”
Constructing the basic walls simply involved stacking the bales as if they were giant bricks, then securing them to each other by hammering hazel stakes through their centres. The only thing Dale had to be careful of was to ensure the bales were laid in such a way that their straw ran horizontally, as this is the only way to prevent them from sinking into each other.
As straw walls need to be able to breathe to prevent the accumulation of moisture and rotting, placing them on a plastic damp-proof course (like one would when building with brick) is out of the question. So instead Dale placed them on top of his 45 cm high dry-stone foundation walls – that way, any moisture that finds its way into the walls can drain harmlessly out of the bottom into the ground.
Before finishing the walls off with a protective yet breathable render made out of a mix of sand and lime, he trimmed the bales to ensure they were all nice and smooth. “I used a chainsaw for this job. A hedge trimmer would probably work better and garden shears will do the job too, albeit a bit slower. I have also spoken to people who swear by an angle grinder fitted with a metal cutting disc.”
Having chosen such an unconventional structure as a home, the last thing Dale wanted was to fabricate a run-of-the-mill floor. “Instead I decided to go for a completely experimental technique which seems to have worked well.” He started by covering the ground with builder’s damp proof plastic. On top of the plastic he placed scrap wooden pallets before covering the entire floor with a single layer of straw bales. The floorboards (reclaimed crate lids, each measuring 2 x 1,5 m) were laid directly on top of the straw and joined together using wood scraps. “This was very easy and cheap to do. It made a floor that’s not completely flat or level, although it’s perfectly practical. It’s also quite springy, which I quite like.”
Other features Dale added included solar panels (for lighting, music and computer), compost toilet and a fridge that’s cooled by air coming underground through the foundations. The flue of the wood-burning stove goes through a big lump of stone and plaster to retain and slowly release heat. Water is gravity-fed into the house from a nearby spring. And water collected from the roof runs into his pond, enabling him to water his garden.
What makes Dale’s feat so impressive is the fact that he had just a modicum of building experience before he started. “My only experience was having a go at one similar house two years before and a bit of mucking about in between,” he explains. “My main relevant skills were being able-bodied, having self-belief and perseverance. Plus, of course, having a mate or two to give a lift now and again. This kind of building is accessible to anyone.”
- To find out more, visit Simon Dale’s Web site www.simondale.net/house
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