Stumbled across this fabulous blog post rounding up a bunch of different straw bale and cob builds. Kim links to some blogs I’d not heard of before as well, so going to take a look at those! Well worth a visit.
Archive for the ‘materials’ Category
Strawbale and cob
Sunday, January 17th, 2010Insulation isn’t everything
Tuesday, July 22nd, 2008If there’s one thing that drives me potty, it’s seeing a house described as “eco-friendly” just because it has really good insulation. The latest offender is an article in Build It’s August issue, (page 54 if you’re curious), which says “because of its high insulation values, [this house is] eco-friendly to boot.”
Reading on, we find out that the house is made using an insulated concrete formwork, i.e. they stack up hollow polystyrene blocks like giant lego and pour concrete into them. So that’s polystyrene, which is made from petrochemicals, and concrete, which produces some 5 – 8% of the entire world’s CO2 emissions. Neither material is particularly environmentally responsible or sustainable.
Although the owners have underfloor heating, they don’t use it, relying on an Aga and heated towel rails instead. One of the owners is quoted as saying “We keep it as a steady 75 degrees [24C] and the Velux windows in the [upstairs] kitchen area are left open all year to prevent it getting too warm.”
Agas are not known for their environmental credentials, specially as most of them run on fuels such as oil, and if the house is so hot that the windows need to be kept open to regulate the heat, that’s a big waste of energy.
We are later told “The eco-element of the house extends to the wall finishes – every wall has five coats of beeswax, applied directly onto chemical-free plaster with a sponge.” But I’m not sure how the use of beeswax balances out the use of all that concrete and polystyrene.
I guess there’s two ways to look at this: either the house includes a lot more environmentally sound materials and practices than the article tells us about, or it’s not actually eco-friendly at all. It may be really well insulated, but can’t be our only marker of sustainability. Indeed, as it’s presented, I find it hard to understand why this house is being labelled as eco-friendly.
Lovely recycled glass surfaces
Friday, July 18th, 2008When I was at Grand Designs Live, I was taken with the GLASSeco work surfaces installed in the Log House.
I was really impressed by the depth and luminosity of the material, specially when it was lit from underneath. Having finally had a chance to look into it a bit more, I’m even more impressed with its green credentials.
GLASSeco surfaces are made of 95% recycled materials, including local waste glass, which would otherwise have gone to landfill and which they source themselves from the hospitality trade. The glass is sorted by colour, cleaned, smashed into chips, and set in a solvent-free resin which is poured into a bespoke mould. They can include all sorts of other recycled materials in with the glass chips too, including crushed oyster, clam and other seashells, or aluminium filings.
GLASSeco is available in a number of colours – I particularly like the ones with big chunks of green glass in them – and matt or polished finish. It can be made into work tops, tiles, floors, steps, or stones; can be used inside or outside, or even in a wet room or shower; and can even be made into tables.
This video from GLASSeco explains more about the manufacturing process, and also explains about their factory’s green credentials:
Prices for a GLASSeco work surface start at £270 per linear meter, but each one is bespoke and unique.
This definitely goes on the list of things I’d rather like in my house!
Hemp and lime infill
Monday, July 14th, 2008I’m very keen on the idea of building a oak-framed house, preferably one with lots of big windows and the posts and beams exposed. Oak is beautiful, sustainable, and strong, but the question I’ve been struggling with is, what do we use to fill in the gaps between the oak posts and beams?
Cob is, of course, an option, but if we end up with a plot that doesn’t have the right sort of subsoil, or not enough subsoil, to work into cob then we’d have to bring some in, which would leave a big hole somewhere. Cob is also very labour-intensive, and cob walls end up very thick – 450 – 600 mm thick, according to the Devon Earthbuilding FAQ. I really don’t want the walls of my house to drown out the oak frame and I worry that perhaps cob might do that (but I’d welcome any cob experts who want to weigh in on that point). It also takes quite while to dry out, which slows the build down.
Straw bales are another good, eco-friendly option, but they suffer from the same wall thickness issue as cob. Straw bale walls tend to be about 450 – 500 mm thick, which is similar to cob and again, seems to my novice eye to be a bit thick.
In July’s Self Build & Design, I discovered what might be the answer – hemp and lime (HL). Unlike cob and straw, HL isn’t a load-bearing material, but if we’re using a timber frame, then we don’t need the infill to be load bearing. Hemp and lime is a good insulator, requiring no additional insulation and no cavity, and it’s environmentally friendly – sequestering away over 110 kg of CO2 per m3 of wall covered. It also allows for much thinner walls of just 300 mm, and can be clad in anything from render to timber to masonry. Like cob, HL gives you lots of thermal mass, i.e. it warms up in the sunshine and releases that heat when the house cools, a sort of passive solar heating.
In terms of construction, whilst you can go the complicated way and spray the stuff on, you can more easily build HL walls by using shuttering, i.e. put up sheets of plywood and pour the mixture into the gap. According to Self Build & Design, it’s not the cheapest material at about £68/m2, but then you do save money because you don’t need to buy additional insulation.
Like many ‘alternative’ building materials, there are issues getting planning and building control officers to accept it, as many of them are not up to date with unusual building materials. But Hemcrete, produced by Tradical, have been through all the tests and can produce the relevant certificates.
Obviously I still have a lot to learn about building materials, but I’m really rather attracted to HL. If you have opinions on cob, straw and HL, do leave a comment!
Bury trees, or use them for building?
Friday, June 13th, 2008Whilst I was away on holiday in the US last week, I had plenty of time to do some reading, and I took the opportunity to work my way through half a dozen recent issues of the New Scientist, as well as read some American house building magazines. I came across some interesting stuff, one of which was an article by Richard Lovett entitled Carbon Lockdown (3 May, page 32 (behind a paywall)), which posited that a good way to reduce CO2 in our atmosphere would be to grow lots of trees for burial, thus sequestering the carbon underground.
Atmospheric scientist Ning Zeng is convinced that if we buried enough trees – where ‘enough’ equals ‘half the trees that grow each year’ – in such a manner that it doesn’t decay, we could offset all our fossil fuel emissions. Other schemes involve burying ‘biochar’, which sounds a lot like charcoal, or hydrothermally carbonised biomatter.
Another tactic is to reinvigorate the wold’s marshes and bogs, which naturally sequester CO2 in plant matter that’s turned into peat. This is already being done in places, not just for carbon sequestration but also as a way to protect and extend endangered habitats.
But here’s a thought or two. Firstly, it’s not an either/or situation – we can probably embark on all sorts of carbon sequestration projects. No one method is going to save the world on its own. Secondly, instead of burying wood, why not just use more of it in building and furniture making?
Wood retains its CO2 content so long as it’s not rotting, which means that wood used in a house is as good as wood buried in an anoxic environment, so why not use more of it? Our forefathers grew wood as a crop, projecting their needs a couple of hundred years into the future and planting trees accordingly. Many forests are now similarly managed, and if we treat wood as valuable crop, instead of as a sacred cow, we can use a lot more of it than we currently do.
I’ve noticed that some environmentalists feel that chopping down trees is the biggest sin we can commit, but we need to draw a very clear line between sustainable and well managed wood resources where trees are planted to replace those cut down, and pristine forests that are being raped and pillaged by ruthless loggers and desperate farmers. We need more crop trees, and we need to go all-out to protect our endangered forest habitats, but we can’t turn our back on all wood and treat every tree as if it’s sacred.
The way I see it, more wooden furniture, more wood used in house-building, and more innovative uses of wood, such as turning it into insulation, could both reinvigorate our forest-based economy and help us sequester carbon. A side effect would also be to provide us with a higher-quality and longer-lasting furniture, for example, or a warmer feel to our car interior finishes – nicer, more enjoyable day-to-day environments.
Burying wood seems like a waste when we can do so much more with it.
Another view of Black Sheep House
Thursday, June 12th, 2008I had an email from Peter MacLellan the other day, telling me about a “360 degree immersive image” of the interior of Black Sheep House that he put together for the builders, Miles of Harris Construction. He says it “shows all the exposed timberwork before it was plastered. Amazing joinery – it’s a pity it was largely covered up.”
And so it does! Well worth a look, particularly at the roof, which is a little bit more complex than your average. Beautiful work.
GDL08: The House That Kevin Built – In all its glory
Saturday, June 7th, 2008In the closing hours of Grand Designs Live, I finally got a chance to get up close and personal to The House That Kevin Built. It was a lot of fun to get in there and have a look round, especially as I was one of the last allowed in, so I got the place to myself for a while, hence the huge number of photos.
Here you can see right up and under the cladding.
And the rain screen from the lower, unrendered parts of the ModCell storey.
GDL08: The House That Kevin Built – Up to the apex
Sunday, June 1st, 2008Throughout Grand Designs Live, Kevin McCloud and a team of builders, celebrities, and TV crew built a house in the Grand Village, with ModCell’s straw bales panels and vertical thatch on the ground floor, and the Facit building system used for the first floor and roof. Although I missed the very first stages of building, I kept as much of an eye on the house as possible.
The original brief was pretty simple:
To design and build a sustainable house, using traditional materials and techniques alongside cutting-edge 21st century technology which underpins [Kevin's] green principles.
When I arrived, on the morning of Day 4, the bottom storey, built by ModCell, was already complete and work had started on Facit’s half. The straw bales panels were all in place, but had not all been lime rendered. The glazing and window/door frames were also absent, but you could already get a sense of how the house was doing to look.
One panel was clad in vertical thatch. I heard that this was the first time that vertical thatch had ever been used in the UK, and whilst it looks kinda cool I have my doubts about it. Firstly, the individual stalks of thatch come out really easy, and are very tempting to pull at for the fidgety-fingered. This leads me to believe that the thatch would thin out very quickly, and the more thatch is pulled out, the less tightly packed the remaining straw or reed is, and the easier that comes out… Secondly, it would be a haven for small insects and spiders, which is fine on the outside, but less keen on that internally.
The other side of the house, showing rendered ModCell panels and one left open for later glazing.
The second storey, supplied by Facit goes up really quickly.
The Accoya wood doors and windows, from Westgate Joinery, go in. Accoya is basically softwood that has been treated with acetic anhydride at temperature and under pressure to give it the properties of hardwood. This means that it can be sustainably sourced, and the treatment makes it incredibly durable. I had a chat with a chap who was a real Accoya fan, and he told me that the manufacturer’s guarantee is 30 years, with the importer adding another 10 onto that – that’s showing a fair amount of confidence! This build was the first time he’d seen Accoya in the flesh, as it were, and he was getting really quite excited about it.
I have to say, the idea of a sustainable hardwood substitute really is quite exciting because it would reduce the need to cut down slow-growing hardwoods or use environmentally unkind treatments for softwoods, all of which is much better for the planet. Even the by-product of the hardening process is recyclable – it’s acetic acid, or as we usually call it, vinegar. Not that you’d want to put this vinegar on your chips…
The build progresses, and the roof goes on.
The holes at the top are for piping in insulation.
Work goes on inside, hidden away from nosey bloggers, sadly.
The Facit panels for the apex of the roof are so light that they could actually be carried by one person.
Kevin McCloud setting up for recording.
Kevin indulges in a bit of pole dancing.
Kevin does his piece to camera. I wasn’t close enough to be able to hear what he was saying, but I asked Finlay White from Modcell about the panel that he’s standing in front of, as I really couldn’t figure out what it was supposed to be. Apparently, it’s a silica aerogel window which soaks up solar heat during the day and releases it during the night. According to the Channel 4 site, this particular panel was of Cabot Nanogel.
More photos in the next post!
GDL08: ModCell and The House That Kevin Built
Thursday, May 29th, 2008Right at the end of Grand Designs Live, as the exhibition was shutting up shop, I finally got the chance to have a look around the House That Kevin Built (big post to come about that soon!). Whilst I was snapping photos, I got to talk to Finley White from ModCell, whose company put up the bottom half of the house.
The ModCell bits are the ground floor panels you can see either rendered or, on the left-hand wall, glazed to show the straw off. Glazing the panels is not normal practice, but it was nice to be able to see the straw inside in this instance. Essentially, these are wooden frames (sustainably sourced, of course) that have been filled with straw bales and then rendered with a lime render, making them super-insulating and vermin-proof. All this is done in a ‘flying factory’ near to the build site using local materials to reduce the amount of transportation required.
The panels can then be assembled very quickly and easily on-site and as they are already rendered, the structure can be made water-tight very easily. Finlay also explained to me that builders generally dislike having straw bales kicking about as they have to be kept bone dry throughout the build, have a tendency to shed straw which then gets everywhere, and are a bit of a pain in the neck. ModCell, on the other hand, deals with all the straw away from the build, keeping the site tidy. As all the rendering is done in the ‘factory’, you’re also less at the mercy of the weather – joy to any British self-builder’s ears.
I was really impressed with the idea, and it’s a real shame that I didn’t get to talk to ModCell earlier in the week as I would have loved to have done some video with them. They have lots more information on their website, including a load of photos from the Grand Designs build.
GDL08: Container living
Monday, May 19th, 2008If you’re looking for a quick build that’s a little different, why not live in a shipping container? Already waterproof, and able to be sited almost anywhere that’s flat – only the corners rest on the ground so you don’t need to lay lots of concrete – you can whip up a container house in no time. I had a look round an empty 20ft container on the Lendon Containers stand, and they are surprisingly large with a lot more headroom than I expected. A bit long and thin, perhaps, but join a few together and there’d be more than enough space. And they can easily be stacked – containers on ships are often piled up to 14 high – so there’s no problem if you want a two storey house.
Price-wise, they’re not all that expensive. The nice chap from Lendon said they went for £4k for a 20ft (if my memory serves) although you can probably get them on eBay cheaper if you want to fit and install them yourself. I’m not sure how much a whole build would cost, if you were to make an entire house out of them, but I suspect it’s much more affordable than bricks and mortar.
Indeed, GDL had three containers decked out as a bedroom, lounge and full bedsit, and stacked three high just to show you how easy it is. Sort of like giant, habitable lego. The beat-up exteriors look great in an urban setting, but if you’re out in the countryside do you really want a heap of rust in your garden? Well, that’s easily fixed – containers lend themselves well to being clad in whatever material you want, and you can even put a living roof on them to soften the angular look even further.
The bedroom container was bigger than our bedroom is here, and although it was a bit longer and narrower, they got more furniture in than we can, so a container wins in the “vs our flat” challenge. Standard width and height is 8ft by 8ft 6 ins, and length can be 10 ft, 20 ft or 40 ft. One day I’ll have to work out what our flat’s square footage is, so I can do a proper comparison.
The lounge container is probably smaller than our lounge, but then, ours has a kitchen in it too. Put two containers together and whip out the middle wall and you’d be laughing, though. Containers can be well insulated – although there’s a trade off as the thicker the insulation the more space you lose inside – and can have windows, doors, shelving and air-conditioning fitted, so they’re easy enough to turn into a useful space.
And if you want a speedy guest bedsit, or you want to live on-site whilst you’re building your house, there’s just enough room in a 20ft container to do that.
I was thinking the other night… ok, fantasising, if I’m honest… that what I’d do would be to have a container on-site to securely store all the materials that come early, to keep them dry and safe from acquisitive hands, and then once the build was done, move it to the back garden, clad it in cedar or something else that looks nice, bung a living roof on top, and bingo – instant garden shed!
