Bristol Green House Blog

Tyre walls
Straw bale walls
I-beam roof
Living roof
Clay/Lime render
Thursday 16th July 2009

The seven bale wall is now re-rendered in lime render. We did this over two sunny volunteer weekends. As before, we had an interesting mix of people attracted by alt. building and Sally's delicious lunches. The ripping off of the clay render was too painful for me to watch, but the lime went on quickly. We did the first coat one weekend and the top coat the following. I have done some rough calculations of material quantities which I have added to the render page. I have also added some notes on using hessian to keep the render moist and the re-use of year old render.

removing clay renderRemoving the clay render - I couldn't look.

Monday 1st June 2009
OK,OK, I admit I made a mistake!

I have bitten the bullet and decided to remove the clay render on the exterior of the 7-bale wall and replace it with lime render. It's a pain in the bum, but will be worth it so I can stop worrying about dampness in that wall. My remedial action of painting on very thick lime wash (see my deluded entry directly below this one!)didn't work as it started to flake at the bottom of the wall. Jim Carfrae has now fitted damp meters so I can keep an eye on dampness levels in the straw. These are very encouraging, except for the sensor at the back corner, where the straw wall joins the tyres next to the sandbag wall. This is the (perhaps unsurprisingly) dampest spot, though not at a critical level.

Tuesday 19th August 2008
Rain? Pah!
Clay render IS waterproof...
The initial failure of the painted clay-rendered exterior wall to be waterproof was a big setback. Now having coated it in 3 coats of limewash, then the 3 coat system of the Keim active silicate, Granital paint, the wall is waterproof. So far, all the downpours of this so called summer have failed to moisten the wall. All I can say is phew!

So, it IS possible to render the exterior with clay.

You can see here just how uneven our top coat still is even after being painted with an extra six coats. Lesson: take more time to get a perfect smooth finish.

Tuesday 22nd July 2008
Stone finger points at truth
Digging has revealed a fine stone phallus dating from the final years of the carboniferous era, just before the big whimper. Archaeologists speculate that it is the tombstone for the doomed inhabitants of 21st century Britain and the site of orgiastic celebrations of excess where they consumed jet transported delicacies wrapped in endless layers of cellophane.
The beauty of a living roof
They were a primitive society who dwelt in man-made caves of concrete and fought endless wars for control of minerals whilst destroying the abundance around them. They were doomed until one day a woman started building with straw...
All the work and expense of putting in extra roof structure, lumping all that soil up the ramp, hand-picking all the broken glass from the soil (we built on the site of old green houses), was worth it to have a lovely, gently sloping lawn in mid-air.
The garden is finally recovering and looking beautiful thanks to Liz's planting and the well executed landscaping by Rupert and his team to hide the displaced soil from the build. You can just see the building at the end, still tarped. More on the render soon...

Thursday 1st of May
It's amazing what a bit of a tidy up will do. I took this through the window at the back. Not looking too shabby though.

Newt News!
The newts have been getting frisky, doing their strange mating dance and laying eggs in the new pond. AND I found a fox sleeping on the roof last week.
Monday 31st March
The internal rendering is done and four frogs and one newt have been sighted in the new pond.
AND the garden is sprouting wheat all over (see left)

Nature is reasserting control after winter, making the building site a garden again. The wheat has spontaneously appeared because so much straw was scattered around the garden. I should pick it and make a nice wheat grass smoothie. I'll report back on the rendering once I've done the lime washing.
Friday 29th February 2008
Testing provokes last minute change of render material.
Hand break turn
As I approach the second year of this self-build project I still have to be as nimble as at the start. With volunteers coming on the Saturday to render the interior, on Friday morning I decided to switch from clay to lime as render material, giving me just hours to source the materials.

As reported earlier, the external clay render, painted with Keim active silicate Granital paint, has failed to be waterproof. The salesman from Keim came to do some tests (pictured left) on Thursday and the results weren't good.

Interestingly where there are absolutely no cracks or blemishes in the surface of the paint then it is waterproof. If, however there is a tiny hair-line crack or dimple, the water enters and the liquid in the glass device drops very quickly. Worse still the paint appears to not have been absorbed to any depth in the clay meaning that the paint chips off very easily. Removing the glass device for example would peal off a circle of paint.
A little bit of digging into the clay render revealed that although the surface was hard, underneath the structure was weak and powdery. Rather than storing up problems for the future I decided to switch the render material to lime.
Lime v clay render

Lime is a fascinating material and a great alternative to cement with a much lower embodied energy footprint, but it is much less pleasant to use than clay. It has to be kept off the skin as it sucks out all the moisture. Clay is very good for the skin. Lime is a much more industrial product, akin to concrete, clay is more like mudpies or sand castles. Lime marks the woodwork when it splashes on. Most importantly of all the clay I'm using is from my garden and the lime I bought had come from France.

More tests?

Now I have to work out what is wrong with my clay mix and decide if I need to remove it all from the exterior and start again. This is the apocalyptic scenario I have been refusing to contemplate. Now it looks more likely. The other question is why did the Keim paint not absorb into the clay? Is this due to the structural weakness of the clay?

I have so little time available for the build now and I'm so desperate to finish, that I barely have time to do the tests required.
Above, trimming straw to 1 inch lengths to add as 'hair' to the lime render. Below, the lime rendered wall.
I would have to do a new set of test patches to see if a lower proportion of sand or the use of different clay makes the difference. I hope I can make time for this as I love the idea of clay as a building material and I'm afraid the failure in this case will put others off.
Timely tips for wannabe self-builders:
Don't do as I do, do as I say. If you are going to try untested stuff - do the testing yourself and do it properly!
My lime render recipe

This is based on the recipe I learned volunteering on another job and I think it originates from the Alternative Building Co.

1 buckets Hydraulic lime (NHL2)
3 buckets sand (lots of different sizes of grains
Half a spade of lime putty
Half a bucket of straw cut to 1 inch lengths
As little water as possible to make it sticky. (The lass water the less it will crack later and note that the longer it mixes the wetter it becomes)

As with everything in self-build you will get completely contradictory advice if you ask more than one person. Some people just use lime putty at 1:3 with sand, others don't use the putty at all. What I did was dissolve the putty in a little water at the start so that is stickied up the whole mix. Adding it later may leave it in clumps.

Rule breaking, again.

You are supposed to do two coats, but I have attempted a single coat to see how well it works. I'll report back on cracking and strength when the render is dry in a couple of weeks.
Tuesday 29th January 2008
We sir, render!
Yes indeed, sir (and madam), we do.

Volunteers needed,
16th and 17 Feb, 2008

It's time to get our hands dirty again, this time to render the interior. We are going to attempt it in a single coat, which will require much more attention to detail and professional finishing. I just can't bring myself to do all of this twice, hence the desire for all in one. If Dulux can do it, so can we muckspreaders.

We'll be mixing and applying render over all interior walls and attempting a wonderful smooth finish. Are you up for it? Send me a mail and let me know.
Rendering is a wonderfully tactile and sociable activity and all the events we have done around rendering so far have been very enjoyable. I've met lots of interesting people doing this and everyone gets fit.
Read more about rendering here.

And the blog here
Timely tips for wannabe self-builders:
Don't ever believe that tarps are actually waterproof.
Friday 28th December 2007
When I launched myself into this project 20 months ago I had little idea of what I was getting myself into. I rightly supposed it would be physically and mentally demanding but had no idea how wonderfully social it would be nor, on some desperate occasions, how lonely. This self-build lark is not for the easily defeated.
Now I am tantalisingly close to having a space I can move into, albeit one with loads more work to do on. These last stages are painfully frustrating as I have less and less time to devote while I work to pay for the whole folly. My methodology of recycling everything and searching for the most eco-friendly materials is a pain in the arse. It is so much cheaper to buy regular planet-destroying products and just throw away your waste rather than storing it, processing it and re-using it. Some of my choices have resulted in huge extra expense, for example insulating the roof with straw took so long, despite the low cost of the materials, that it is more expensive than insulating with spun gold.
The latest trial is that the render on the 7 bale wall (see image of it's deceptive beauty above) isn't water proof. AAAAARRRRRGGGGG.

I always knew I was taking a risk by rendering with clay on the outside and in retrospect I should have done a test patch and thoroughly experimented on it. (Hindsight is a wonderful thing.) My first priority next year is to put aside some time to talk to the paint people about why their 'active silicate' paint didn't work and the straw people about any alternatives. We need to find a way to fix it without having to rip it all off and render with much more sensible lime.

As a seasoned eco-nutjob builder this setback is mere water off a crude oil drenched ducks back. I have no choice but to soldier on, so I may as well enjoy it. It'll be over by Christmas.

Happy New Year.
Timely tips for wannabe self -builders:
Budgets are a form of fiction. If you ever hear yourself saying, "It'll cost x amount," apply the following formula. Budget = x times 2, plus x and a little bit more.
Sunday 18th November
Blidy luvly innut? The 7 bale wall is rendered and painted and looks absolutely fantastic. Finally the tarps are down on the southern side of the building, a day I and the neighbours have been waiting for for literally years (we're over 18 months into this now)
This wider shot reveals a truer picture. Both ends of the wall need more work, the roof edge is still to be done, the stairs to the roof remain to be fitted, the path laid, the back wall second coat render applied. And I still haven't quite finished the floor inside. But all in all, it's blidy luvly. I think I need to sit down for a
rest on the deck.
Monday 29th October
is better than no floor at all...
The soil under the floor is very damp so I have added a damp proof membrane to keep the floor itself both dry and airtight. This means I can fill the voids between the joists with straw as an insulator, which means the place is going to be very toasty. Naturally all these features cause major time additions, but, as always, this is the price to pay for being over-eagerly green.

When the building is finished (maybe that should read if...) I'll collate all my notes on all these techniques and make this site into a really handy green building resource. Meanwhile I'll spend all my spare time crawling to the finish line.
Hey, stop popping all those bubbles in bubble wrap and re-use it as pipe insulation instead! They are selling bubble/foil pipe insulation in B&Q for a ridiculous price so I thought I'd attempt a DIY version using old packaging and some silver foil. I made my bubbles double thickness so hopefully its even more effective than the shop stuff.
Wednesday 5th September
Ooooh, just look at that...

Despite the ongoing sill saga (see blog), the thing is taking shape. Theo has invented a nighty for the angle-grinder for when it is used in straw-trimming mode.
He's seen here in Selafield chic demonstrating this clever cross-dressing hand tool which, thus attired, no longer clogs it's vents with straw fragments. The angle-grinder has an Arbortech blade and we've used this method to trim all the bales.
It's dusty, as you can see here, but way less dangerous than using a petrol strimmer with a metal blade, which I've done before. It was a terrifying experience, not least for anyone who wonders by as you swing the thing around.
Friday 31st August 2007
Ever-receding end of the tunnel syndrome
I've written before about how progress can be slow but over the last month there has been massive progress; the windows are in and the deck outside the window is installed. Yet the end is still as far away as ever and I feel like I'm in a tunnel from which I can hardly see my own progress. These considerable milestones are greatly praised by everyone else who sees them, but to me, desperate as I am for something like completion, I can barely appreciate them as there is still so much to do. The rendering can't progress until a series of preparatory tasks are completed. Initially appearing small, these processes now reveal themselves as ever-increasingly complex. Fitting sills to the windows seemed straight forward until I realised I need to add extensions as I have set some of the windows too far back into the bales.
Also, each window needs some additional hardwood framing to compensate for the parallelogram shape of the openings in the straw. This was caused by me loading the roof and not reinforcing the scaff-board window surrounds. All these tasks have to be done before any more render can go on and they have been caused by thinking of everything in advance. My approach has been quite ad-hoc in some respects and now I’m paying the price for my lack of precision. I’m not defeated by this process, simply worn by it, and as the summer draws to a close I’m desperate to finish the rendering so I can retreat inside my straw cocoon and recover.
Monday 9th July
Hands on volunteers stamp their mark
To the sounds of Argentinian tango music, eight volunteers used their feet to stomp clay, sand and cow-pooh into render and their hands to apply it to the straw bale walls. And a wonderful group of people they were, each with a fascinating life, interesting plans and valuable ideas to share. Today, their hands probably still smell of cow shit, but
they hopefully also took away with them some knowledge on how to turn garden soil into a building material and a set of connections with like minded people. Floaty Sarah, for example, is part of the pioneering eco-village called Lammas. Peter works in a council design department and is researching eco methods to build industrial units. Julie is spending a few months
volunteering on organic farms.

Mixing by stamping the materials on top of a tarp and constantly folding the mix into itself proved effective, but each mix took the best part of an hour to make. Does anybody know a faster method?

The final recipe was (your mix might differ with your local clay and sand):
1 part clay
1 part finely chopped straw
1 part cow dung (fresh)
5 parts holm sand (it's our local building sand)
and 7 cups of thick clay slip (just to make the mix more moist and pliable)

Read more about rendering here.
Monday 2nd July

It took weeks longer to achieve than I thought it would, but the green roof is now flourishing. As you can see, once the tarp is removed the building will disappear into the summer foliage disguised as a putting green. The delay was caused by the sheer volume of soil that had to be sifted for glass and stones and barrowed onto the roof.
Now all that's forgotten and the roof, with it's disconcerting springiness, has been fully anointed with several long gin and tonics. It's great when a plan comes together.
Wednesday 13th June
Hitting the one year mark, working on the build at the same time as several paid jobs in London, and build tasks that have taken many times longer than expected, have made this the slowest and most difficult few months of the build. But then, over the last two days, some major progress has been made. My excess bales have been taken to a new home, the Cobthorn trust, who happily swapped bales for cow poo (man, do I need a lot of that stuff. Don't you find that?) This cleared the two huge blue-tarped bale stacks and made way for the landscapers to come in and, rather alarmingly, raze the whole garden. I'm told this is necessary, but I worry about the slow worms who only yesterday lived in a wild paradise of slowly decaying straw bales crawling with tasty insect snacks. This clearance is a highly visual indicator of PROGRESS in the build which has been scarce over the last few months. Then today we found the source of the leak in the bottom of the tyre wall that has been perplexing me for months and months. I have been undertaking all sorts of unsuccessful scientific methods to find the location of the leak in the damp-proof membrane using food dyes. We found it in the end by digging a hole 5ft deep down the back of the building.

Now suddenly lots of other tasks that have been dragging on have come to completion. The extra drain I put in (because of my horror over the leak) is done. The beam that will support the huge window at the font is finally in. And all the soil is on the roof in preparation for the arrival of the turf tomorrow. Progress ain't slow it's meteoric! Finally.
Thursday 10th May
Locksy, Barbara Jones dog, came to sort out a few details in the straw. He brought Barbara along too and a few volunteers. The unusual design of this megalomaniac shed required a two day session of advanced straw bale engineering and it was a great opportunity for the five volunteers to work with Barbara and explore some of the more complex aspects of straw as a load bearing material.
Most straw bale buildings have 4 walls of equal height. This one has three walls all of different heights. Straw has great load bearing strength, but it can't deal with point loads. By removing the fourth wall, the weight of the roof at the front corners effectively becomes two point loads,
so we have installed oak beams mounted on adjustable plates made by Fred Brodnax the local blacksmith (left). These can take the weight of the roof if the bales are trying to compress unevenly.
The volunteers also fixed some additional reinforcements to the ends of the bale walls to prevent the bales squeezing forward instead of down.
A large number of volunteers turned up over the weekend to start work on the living roof.
First we stretched an 11x9m sheet of butyl rubber over the entire roof, cutting a hole for the sunpipe.
Then we put a protective layer of old lino, tarps and leftover damp proof membrane. After that came a thin drainage layer of fine gravel. Then a filter fabric and finally soil, carefully filtered for glass, on top of a little old straw.
The soil will be restrained at the bottom edge by a pretty, yet tricky to make, metal cage filled with plum slate - an idea I got from Piers Partridge, I don't know where he got it from.
Looking out Looking in
Tuesday 1st of May
Many's the time I've been accused of talking shit, but today it's actually true. I'm talking Grade-A organic cowshit mixed with clay from the garden and plasterers sand.

Left: This is the shit!
Right: A donor.
The cows are a Gloucestershire breed from a Gloucestershire organic farm, location of the Ragged Hedge Fair plus plenty prime pats of poo for plasterers.
According to principles laid down by Barbara Jones, I've done test patches with different ratios of sand to clay and poo. The patch that cracks least will be the mix we use all over. The poo adds texture and stickiness and deepens the colour to a lovely shades of earthy, shitty brown. Yum yum.
If we do the whole building in one of these shades it will just about disappear into the landscape. To me the smell of this mix is much nicer than Dulux.

If this works, and there's still a chance that they'll all crack if our clay's not right, all I'll need to purchase is the sand - nature will provide the rest. Fingers crossed.

Place your bets on which patch will work.

If you'd like to get involved in the plastering process let me know by email. It is likely to be the Saturday 30th June and Sunday 1st July.
Tuesday 27th of February

Straw insulation stuffing on Saturday March 3rd

If I were starting again, I'd do the insulation much more simply, buying some nasty blown foam and putting it under the soil on the roof. Ages ago, I decided to use the left over straw and insulate between the rafters on the inside. Although the insulation material costs are almost nil, the fiddle factor is high. At least we can turn it into a group activity and have some fun with it.

So this weekend we start stuffing the rafters and find out how quick it is to do. Several volunteers are coming down and it should be a good day, and it will be good to see some progress.

More details here

Sunday 11th of February

Knowle West Media Centre to be the biggest
straw bale building in Europe.

Honestly, I don't mind these Johnny-come-lately's knocking me off the No.1 biggest straw building in Bristol spot, it's brilliant news to see commercial buildings using straw. Today Knowle West, tomorrow - the world. The Knowle West Media Centre are claiming the idea for straw came from young people on the estate, they also wanted it in the shape of a giant Pokemon, but the architects, White Design, had to draw the line somewhere. KWMC

Tentatively, I'm thinking about the 24th and 25th of Feb to do the straw-dipped-in-clay-slip roof insulation. Let me know if you want to take part.

More details here

Sunday 28th of January

Another fantastic money saving eco-friendly building technique.

When I realised I had to build a retaining wall next to the straw wall I knew only that I didn't want to resort to concrete blocks. I thought about old railway sleepers, rammed tyres, gabions and wooden cribs, but all of these options required too much excavation or bringing too much in.

Above, filling the earthbags. Right, the wall rises.
Finally, after hours of searching on the net, I discovered the simplest and most environmental solution to this particular wall - earthbags. As well as how to make a simple retaining wall I found inspiring examples of entire buildings with elaborate arches and wonderful organic shapes made from earthbags. My first principle of building throughout this project has always been to bring as little as possible onto the site and to throw as little away. In this case the wall is made of my own garden soil, mixed with a little cement in hessian sacks. If the wall were to be demolished in the future, the soil can be returned to growing things.

Read more about Earthbags here.
Monday 8th of January


Next weekend we are going to insulate the roof with straw. In order to 'fire-proof' it we are going to dip the straw in a clay slip (that's mud to you and me).
If we have time at the end we'll try use No. 442, mud face masks.

Read more on our insulation plans, here.
UPDATE 12th January.
I have decided to cancel the roof insulation this weekend. We have successfully done a test section and it is much easier than expected and appears to be working well. Due to work commitments I feel it's better to leave finishing this task until later.
Sunday 17th of December


Have a great holiday and a productive new year. Viva straw (and rammed earth tyres)!


I have been spending a lot of time working on the Green House, but have done little physical labour. I'm back in R&D mode and ordering up materials for the next phase with priority given to some new structural support.

This is a highly experimental building; the first to combine tyre retaining walls and straw bales, the first load-bearing straw bale building to only have 3 walls and probably the first with different heights of bales in each wall.

It is always my natural instinct to mess with the form, as a film-maker and artist and now as a builder. But this disregard for convention has its costs. For a while a few weeks ago I really thought the whole thing was going to fall down.

I noticed that the vertical oak support at the front (now just starting to take some of the structural support role from the straw) was starting to lean a little forwards. If you think about it, the building with a small wall at the back and a large open space on the front is going to want to fall forward. In addition the slope of the roof means that the roof structure is heavier at the front. My fear of it all falling down the hill was exacerbated by the 70 mile an hour winds that, as I lay in bed, made the tarps shriek like wrapping paper being pulled off a present by an over excited child.

In the end I went and stood in the building for a while and it was very, very solid against that wind.
My sensation that the building was very slowly toppling was again exaggerated by looking at how the bales were in relation to the oak verticals. In the front corner, the top two bales were a couple of inches out of line. Had it always been like this or were the bales slowly moving as they settled?

In the end I think the lean was probably caused by us jacking up the other end of the building to replace the bales. And the bales at the front had never been in line with the oak. I know this because we took the oak beam out and dug out the bales a bit more. It was worth it just to be confident in the strength of the building.

Peter Beresford, the fearless structural engineer, has proposed some steel rods to act as anti-racking, in other words if we have these, the thing DEFINITELY won't fall down. Interestingly all the research says that straw has adequate anti-racking strength, but as I have left a whole blinking wall out, a few steel rods will be most reassuring. I'll write up the details of these reinforcements when we come to install them.

Above. Is the building falling down or did we just not cut the groove in the straw deep enough?
Sunday 26th of November


Why is insulation so expensive when everybody needs it? It should be incredibly cheap. It isn't, especially if you want something that isn't a petrochemical product or horrible to handle. Wool, for example is £8 per square metre. I have 65 of those in my roof. If I used no insulation at all it would still take me years to burn £520's worth of energy. So, what can I use as an alternative that is really cheap and a really good insulator. Um, straw?
Used as a loose fill, straw apparently has a similar U value to Warmcel, which would cost £460 for 8 inches of insulation. I paid £3 a bale, and I doubt it will take 153 bales. So we'll do the roof insulation with straw. I have bought a load of second hand ply to create a layer above and below so that the loose fill is not too loose. The ply cost £100, and there will be some fiddling around necessary to fit it, but I would have to do the same if I used Warmcel - it's all about having an air gap between the insulation and the roof. Great, let's get to it!

Ah, yes, my dear friends, I forgot to mention, there is a catch. In order to render the loose fill straw fire proof it is recommended that it is dipped in a clay slip first. I find this very amusing. If there's one thing I've got a lot of it's clay. So, here's the deal. If you want to learn the art of cheap, locally sourced, environmentally friendly insulation AND you like playing mud pies, then come on down, cause it's gonna get messy. PS, Clay is VERY good for the skin. This will now happen some time in 2007.

Saturday 25th of November


The pace of the build changes all the time. Lately, progress on the build has ground to a halt, but I've put a lot of work into making sure it stays dry and making it into a useful work space. What I really want is a rain free day so I can put the next layer of felt on the roof.
I've fitted a door (above) and some clear plastic where the great window is going to be, (left). You can also see the tent that used to be the workshop, hanging out to dry and the second-hand steps that will eventually lead up onto the roof.
(Right) Here, you can see the imposing height of the front as seen from the neighbour's garden. The wall in the foreground is all that is left of the original green houses. The rest has been recycled into the gabion foundations.
Monday 13th of November

This week I had several visitations. Five members of Structural Solutions (left), the structural engineers who did the calcs on the roof came and speculated how these building techniques would work in the Caribbean.

Four civil engineering students from the University of Bristol who are designing a community centre came by and were very civil and apparently quite inspired.
It's nice to be able to show the place off.
Thursday 9th of November


I spent two days up a tower stuffing the wedge shaped roof plates with straw as insulation. The result of all this hanging upside down in unusual bracing positions is that I have developed more muscles than a Moules Marniere. I am fit, it's official.

So today I started messing around with some highly toxic glue to stick the roof felt down around the sunpipe, just to counteract the positive health benefits.
So many of the products available to builders are petrochemical and/or toxic. I spend hours and hours looking for the least nasty products. In the case of insulation materials anything green is ridiculously, laughably expensive. The nasty rockwool or polystyrene type products are much cheaper. I have arrived at using this nasty adhesive (which doesn't even seem to work, so far) because I don't want water ever going anywhere near those bales. I have submitted to the dominant ideology on this one. In the US you can have your cavity walls filled with a Soy oil based foam. The Canadians have gone even further, check out soap based insulation!

There is such an opportunity for greening the building trade. I only hope the blinkered morons that run UK industry will look around and see the possibilities. B&Q sell wind turbines, yes, but they also only sell wood stains that are toxic. Given the choice I'd always go for the least toxic, but often we are not given the choice.

Friday 20th of October


Blimey, the roof is on. We've done the first layer of felt (there will be two layers of felt and then a pond liner) and we've even done the edge that will hold in the soil and turf. I am hugely relieved. I can relax for a few days without living in fear that the bales will get wet again. Phew.

The photo shows the roof and how the building is surrounded by trees. Beyond is the Ashley Vale and beyond that Bristol. Beyond that... who knows?

Thursday 19th of October

The edges of the roof are made up of Kerto beams. This is the proprietary name for laminated wooden beams, like plywood about 90mm thick. It's very strong and can be made out of younger trees than conventional beams. When the lorry arrived with two of them at 10.1 metres and eight at 7.5 metres I really didn't know how we were going to get them down the long slope of the garden. All I could think to do was recruit loads of Dexter's school friends, strapping 16 year-olds, to lift them half-way down the garden, six to a beam. Now we have mastered the art of Kerto-manipulation; three people for a 7.5 metre beam. Two at the front, holding a short plank underneath it and me at the back with the end in a wheel barrow.
Then we put them in place using a winch and an A-frame made out of three scaff poles. In fact the bracing poles for a scaff tower are deal because they have shorter cross beams attached. This makes the beam float above the joist hangers.
All that's needed then to make them fit is some gentle persuading with a sledge hammer. Handy tool the sledge hammer.
The simple roof design really proved itself when we were able to lift it by a few inches to allow us to get the compressed bales out and put fat new ones in. The entire wooden structure at the top of the picture simply lifted up.
Monday 16th of October


Over Saturday and Sunday, Anna, Mike, Stewart and I replaced all the rotting bales. In fact we replaced around 40 bales and restored the building to its full glory. I even took the opportunity to add two new windows. We must be seasoned straw balers by now as just four people did what ten of us did the first time round.

Next we get the felt on the roof before it happens all over again.

On the left of the top photo you can see the three accros that we used to lift the roof. We had to replace all the bales in the back wall and half of the four bale wall. I managed to put by back out at the start of Sunday, but it wasn't so bad that I couldn't hobble around and make up some new window frames from scaff planks. We were going for it a bit on the Saturday and that's when these pulled muscle things happen. Anyway, I'm ready to put some more Kerto beams in this morning.

We had such mild weather (and dry) over the weekend, just as it was announced that this year was the longest summer in 500 years. Its ironic that global warming aids straw bale building. I watch the BBC 5 day forecast as though it might actually mean something. I just want the roof finished, but we have to get the last beams in first.

The photo on the left, here, shows just how mouldy a soaked bale can become.

Once again this weekend, straw proved how easy it is to work with, yet this photo shows how vulnerable it is as a building material. Deep, huh?

Sunday 8th of October

Having looked at the rain damage to the straw bale walls I think we'll need to replace about 25 bales. This weekend several volunteers came round to help go through the stack of spare bales and sort out some dry ones. Oddly, when I calculated how many bales I should buy from the farmer, I hugely over estimated. Now we will have just the right number for replacing the damp ones and filling in the roof plate. I'm hoping to get the walls repaired and roof finished over the next two weeks.
Wednesday 4th of October

I have arrived back to a straw bale nightmare. The people I entrusted to make the building safe from rain, completely, utterly and inexplicably failed to do just that. They decided to leave a 2mm gap in the roof boards directly above the bales. The result is that two walls of three have received a thorough soaking. I have tried blasting the bales with hot air, but to no effect. Approximately 25 bales will need to be replaced.
Monday 25th of September

The roof is on, it's not finished but the beams are in and the OSB board is on the top of it. The straw walls are protected from the weather while I take some time to do some paid work. We have had a mad race against time to get everything done before my job started and we almost made it. I brought in Ben from the Low Carbon Network to help finish the placing of the roof beams after I'd gone. Then my two main helpers put on the roof boards.

Sunday 24th of September

On top of the straw on the two long walls is a wedge shaped roof plate. These were made in sections which we screwed together. I made them slightly too big and they were very heavy to lift that far up. With a lot of movement of scaff towers we managed it. The wedges were then persuaded into line above the vertical oak beams. Despite somewhat dodgy carpentry skills and the use of recycled timber (read: warped timber) the roof plate is pretty much right over the floor plate.

Persuading the straw bales into line is then the most enjoyable job of the whole build. The bales move so easily and they look so good when the wall is all straight. Aaaah. With the plates on and a few i beams across between them the building is suddenly incredibly sound. Before that the 7 bale straw wall was slightly wobbly and we battened it up a lot for the placing of the plate.

The hardest job so far has been fitting the Kertos to the roof. These are the beams that are rather like 90mm thick ply wood. A Kerto runs the length of the roof on each side, that's about 10 metres, and they are very, very heavy. When I started the job I didn't consider the roofing part in any great detail. Now I know it's very difficult and time consuming. With the tyres and the straw I hired someone who knew how to do it to guide us through. With the roof we just did it our selves.
Friday 8th of September

The roof plate is fitted to the back wall, seen here with the first i-beam in place. Section by section we will move forward adding i-beams as we go.

Thursday 7th of September

I managed to clear out the Bristol Wood Recycling Project of all usable 2x4 so have resorted to buying new timber. This is just as warped, but I don't have to worry about woodworm. The picture to the left shows just how sophisticated my woodworking has become over the weeks of making up the roof plates (Still not all finished). This one was made up the £32 mitre saw from B&Q rather than the expensive one I hired for a while. I chose to put the roof at 5 degrees as mitre saws have a click point at 5 degrees making it easier to set.

The weather today was glorious so we had all the covers off for the first time since we put the walls up. The panorama above shows the full extent of the shed/stadium.

Thursday 31st of August

Lesley Chenery of Amazon Nails was the perfect facilitator of the straw bale weekend and we got all the straw walls up in four days. We started baling a day late, but that's not a bad discrepancy over three months.

Ten green balers, sitting on a wall...
Below, four courses of straw. I don't have photos of the whole thing yet because it is covered to protect it from rain. I'll get more pics before we fix on the roof plate.
All the volunteers are confirmed in their love of straw as a building material. Just the smell of it alone is enough to make you realise it is great to work with. Then there is the speed with which the walls take shape.

The I-beams have arrived. Now we need to, step by step, work through the process of putting the roof on. It will not be as simple as I'd hoped. The walls are very wobbly until they are loaded which means that we have to pre-tension the walls before it's safe to put the roof on. More on this as it happens.

I call this Japanese Sunrise, it's made in mixed media of recycled timber wall plate and left over thermal insulation.
Sunday 20th of August

An excellent weekend of sorting out lots of little and not so little jobs with Emma, Kate and Dugs. The race is still on for next weekend, but we made good progress over the last two days. And it didn't rain.

We hammered in the rebar that runs trough the tyre walls and the wall plate. We insulated the first plate and closed it up and cemented in the second plate. All these little jobs take so much time. I had a pleasant weekend chatting with volunteers as we worked. Thanks people.

Thursday 17th of August

The first wall plate is cemented in place. The second is made, but not yet fitted. We have another week until we start straw baling so lots to do.

Left, the wall plate wot Stewart made.

Monday 14th August 2004

Poor volunteer turn out again. Only Stewart came to help, but by the end of Sunday we had made some progress. This stage is fiendishly complicated, mainly because there is no methodology. Everything has to be thought through before any action can be taken. And everything has to be done in the right order. The problems are to do with how to protect the plastic DPM and how to fill behind the tyres without pushing the foam and DPM out at points where the level of the wall changes. In the end we poured concrete in behind the tyres on the three corners to make it rigid. This is a real shame, but the only way out of the problem. Now we can fit the first wall plate. This has to be mortared into place before we can make the other plates so that we can match up bale heights. Slow, slow progress. Poor Stewart had to watch me take out my frustrations on the hateful pink foam. "I never knew straw bale building was so stressful," he said, quite innocently.

Gazebos become strangely mutated. Repairs upon repairs keep them standing.
Friday 11th of August

We have fitted the thermal insulation to the tops of the tyre walls. Th
is is the best way I can think of doing it, though heat can still escape through the tops of the tyres where there is no thermal insulation. I am finding finishing off these tyre wall very frustrating. The design the Low Carbon Network came with is meant to be buried. In my case because I'm interfacing with straw I can't bury the top of the tyre wall. A wall that is made of thin plastic DPM wrapped around insulating foam seems very weak to me. I will have to find some ay of cladding it to protect it from the damage in the future. This stuff needs to be thought through more if tyres are ever to become a frequently used material in buildings.

Monday 7th of August

I came up with a clever solution to raising the bales above grade, but after another chat with Barbara we returned to Plan A. The french drain I have installed next to the straw wall will ensure that there will be no flooding, so a wooden wall plate of approximately 200mm would be adequate to protect the straw from damp. I will install a wooden "skirting board" to protect the wall plate from damp.

Making the tyre walls different heights complicates the making of the wall plates. Each wall plate has to be a different height so that the bales will meet at the correct level at the corners. See approximations, left.
Sunday 6th of August

At some point on Friday I realised that I had completely misunderstood a key element of the design. I had been told that the bales need to be 18 inches above ground level, but I took this to mean that they could be at ground level as long as they were sheltered from splash back, so I had proposed 18 inches of wood, rather than render. Somehow I finally twigged and I called Barbara to get the low down. She said the bales had to be minimum 9 inches above grade. It was fortunate I realised when I did because we were going to be making the wall plates on Sunday and I had several volunteers coming over to do this.

In conventional building everything is signed off at the beginning. In my case I have done the design myself and then started in order to get the work done over the summer. If I had designed every detail in advance, I would have had to start next summer!

So, after a very stressy night of wondering how I was going to make a timber wall plate 18 inches high, I have come up with a solution which has been approved by Barbara but still needs the nod from a structural engineer. Once I get that I'll put up the details.

Sunday 6th of August (part 2)

We have bales!

Despite the set back of having to cancel the volunteer session today the consolation prize was to meet Chris Wyatt and see him harvest my bales.

Friday night and Saturday were a terrible days of panic over how to resolve the making of the wall plates, but by the evening I had a plan and had spent a pleasant hour or so in the sun watching the harvest.

Left, Chris adjusting the bale size. Below, he measures the outcome. Each bale can differ in length by about 3 or 4 inches. This is a good thing because my tyre walls are not precise multiples of anything in particular. It will make the bale wall building more interesting. He had the bales length set at twice width, ie 350 x 450 x 900. This makes a lot of sense in building terms, but I had done my drawings based on metre long bales so I got him to make them longer. We shall see if this was a good idea in a few weeks time.
Saturday 5th of August

Yikes! I have found a flaw in the plans and so have to cancel this Sunday's session. I need to re-design and get some new materials.

Between 19th of July and 5th of August we worked like buggery, but to little visible effect. We excavated the rest of the site, levelled in preparation for the gabions and dug the remainder of the drain Francaise. I taught myself to use a digger and we destroyed yet another tracked dumper. That is four machines we have tipped or broken. The site is a steep hill and these bits of kit are just not up to the job. One day two Polish lads came in and barrowed clay up the garden. They couldn't understand why we had so many tea breaks even though it was about 30 degrees. They were just incredibly hard working, but when I asked them back at the end of the day they weren't interested. Shame, they were way better than the tracked dumpers. My hippy Bristolian helpers, who have a fag break every four minutes, regarded them as peculiar aliens. None of the Polish work ethic rubbed off.

Because of my green compulsion we cannot take away any of the spoil from the site, so for every scoop I was digging out, the
lads had to find somewhere to put it. Somewhere permanent. We ended up stuffing another 30 tyres to make a retaining wall to contain some of the spoil. For day after day we kept digging, shifting, levelling in the hottest July since 1911.

Then I advertised a fun volunteer weekend of gabion filling and French drain making and nobody turned up. Gabions, once so new and exciting, have lost their glamour. Everyone has their eye on the straw bale weekend. There is a lot to do before we can put the bales up. If Kevin McCloud were here he'd be in a corner somewhere muttering how Rik is not going to hit his deadline. I'd be in another corner muttering the same.

Wednesday 19th of July.

We are just 9 tyres away from completion of the retaining walls. The process of building them has been a lot of fun as well as hard labour. Now two walls stand made with little more than dirt, tyres and sweat.
Rehearsing for our music hall act.
Caroline models our new range of budget furniture.
Ollie, ever ready with sledge hammer and beer...
Tuesday 18th of July

I can’t believe how much George and the volunteers have achieved in the last week. By the end of Monday the two tyre walls are only 9 tyres short of completion. George tells me I now have the third largest rammed tyre building in Britain after the Brighton and Fife earthships. The volunteers have been incredible. I thought they’d just come for a day at a time, but Chloe and Ollie have both done six days each. Chloe wants to become a green builder and Ollie is just a glutton for punishment. Anna and Mike have put in some time too and Stewart has come up from Reading four times now. At first I felt unsure about the volunteering idea - surely I was just expecting people to work for nothing - but the exchange is that they get a chance to learn the principles and the practice of building in as sustainable way as is possible. Everyone is soaking up the methods and sharing their dreams of what and how they would like to build when the time is right. We have managed to put in some serious socialising as well and everyone is taken with the oasis that is Ashley Down and St Werbergs.

In truth I had been dreading the tyre wall building. I couldn’t imagine it was possible to physically do. I spent a lot of time trying to design a mechanical tyre rammer. Unfortunately I had a major building project on so designing and building a hydraulic machine became impossible. Now that we have almost finished it using the physical pounding method I realise it is do-able, as long as you have people with the energy to make it happen.

The tyre wall looks beautiful. Each tyre is so stuffed that it looks pregnant. It is the most voluptuous wall I have ever seen.

So thanks to everyone who has volunteered or helped out so far. To Sally for the universally praised food, George for his passion. Mike for being so into it, Stewart for interesting conversations and great practical skills, Chloe for working so hard, Oliver for working so hard and keeping everyone entertained, Theo and Dylan for their unerring punctuality, Nick Creighton, Alistair, Tashi, Emma, Caroline, Clare, Sue, Mike Court, Anna, Stella, Dexter, Tommy and Angus, Jonathan, Ben, Mischa and Duncan from Brighton, Dugs and Dee from Telford. And everyone else who’s helped so far. Thanks.

Saturday 15th of July

We have a big turn out today with 13 of us on site. Despite cider damage and the endless pain of trying to connect together two pieces of damp proof membrane and then keep it out of the way of the sledge-hammers we get the third course down.

Friday 14th of July

George and the volunteers have been working like mad in the incredible heat to get two complete courses of tyres rammed and a third course in place. More volunteers are due in the morning. Oliver is introducing George to real west-country cider tonight so tomorrow may be a disaster.

Wednesday 12th of July

George returns as do volunteers Chloe, Oliver and Mike and we press on. Tyre pounding itself only makes up a third of the work. Keeping the various layers of insulation in place and back filling in the right way are very time consuming and complicated and take up the majority of the time. I will write a fuller account of the process, the methods we used, and how I would alter that method, when I can.

Sunday 9th of July

We got the first tyre down at around 3pm yesterday. George Clinton from the Low Carbon Network arrived with Jonathan and we have spent most of the time up until 3pm yesterday sorting out the French Drain and fitting the DPM. We listen to the sounds of reggae from the St Werbergs farm fair wafting over the allotments, along with the smell of bar-b-q chicken. We manage to catch the end of the party. Although the work is incredibly taxing, both physically and mentally I feel a real euphoria afterwards.

Mon Dieu, c'est une French drain!
Friday 7th of July

Heavy down pours followed by hot sunny spells have caused the six foot high side of the excavation to collapse two days in a row entirely covering half a row of gabions. We lose a day recovering from this, digging out the gabions and trying to pin the earth back. I now understand the kind of force we are trying to retain. The earth is like a sponge here and the water will drag the earth with it in its desire to descend. This building is right in it’s path, consequently I have returned to the idea of putting in a French Drain around the outside of the gabions. I had decided that the gabions were an adequate enough drain, but I realise that they are, or should be, level, so given the volume of water that falls here and its incredible power we are fitting a drain all around the outside. We are also fitting a layer of pea gravel between the clay and the damp proof membrane (DPM) so that water can easily descend to the drain.

Photo: Stewart Hargrave
Monday 3rd of July.

Building is under way thanks to the lovely volunteers who gave up bits of their weekend to make up gabions, level the ground and start filling the metal cages with bricks.
I'm sure I dropped it somewhere here, it's round and black, made of rubber...

Welcome to the bouncy castle for recyclers.

First thing Saturday morning we visited this rubberised mini-mountain in Avonmouth. We have to have all the tyres the same size and in two hours four of us managed to pull out about 90 195/65/15's.

Friday 30th of June

We had 5 breakdowns of the dumpers, a massive downpour and the excavation is still not finished after six days (double the estimate) but I have cleared enough so that we can do the gabions and tyres.
Thursday 29th of June

There are so many things to think of, and I have to priorities them in terms of thinking about whatever's happening next, first. I just had a brain wave. Why am I planning to put in a French drain next to the gabions when the gabions them selves are effectively the same as a French drain. I sparked a frantic email debate with several contributors some who said I was right and others who said I should have a separate drain. I got in quite a panic, as I only have a few days to make sure I buy the right bits for the weekend. In the end I called Barbara Jones from Amazon Nails and she just said, "Do whatever is simplest." Great advice. So the gabions are now both the foundations and the drains for the foundations.

Friday 23rd of June

We estimated the excavations would take three days, but we've hardly scratched the surface in that time. Only now that I can see how slow progress is that I can begin to grasp how recklessly ambitious a plan this is. Tom keeps urging me to lift the floor level and every time he says it I weaken, then have to harden my resolve once more. Raising the floor by just 100mm would reduce the amount taken out by 6 cubic metres!! I am slowly getting hardened to this process. Stick with the plan. It will be worth it in the end.

Thursday 22nd of June

The garden is so full of wildlife. Everyday as we work I have found a different slow worm, some of them babies from last season and some of them mature adults about 9 inches long. I have found quite a few newts as we have been clearing rocks and there a lots of frogs and toads.

Now that we are dumping material from the excavation huge areas of the garden are covered in mounds of soil and clay.

A major anxiety has been to leave enough areas untouched so that the beasties have places to retreat to.
Friday 16th of June

I have been very busy on this every day and fitting in paid work into the evenings as well. I have found a great structural engineer called Peter Beresford who has confirmed that the design is safe and made some welcome simplifications. I have found a digger man, Tom Phillips, a local garden designer. We have started to build a wood store and create a rubble pile of all the bricks that will fill the gabions. Now I have to make sure I have all the right stuff ordered in time so that we can start work with the volunteers. Gabions came in at £11 each.

Friday 9th of June

Henri, the digger man, didn’t come last week like he said, or yesterday, or today. He sets up a meeting, then doesn't even call to explain why he's not come. Need to find a plan B for getting the site dug.

Thursday 8th of June

Yesterday we finally finished the concrete retaining wall. Progress was so slow, mainly because we didn’t do the foundations well in the first place. I have learned by experience that the old aphorism about firm foundations is true. In truth I am more scared than I have ever been at the start of a project. I have done many very scary jobs in my time as a director with huge responsibilities; somehow this is scarier. It is mainly because I don’t know anything about building. I phoned Piers for some reassurance and he laughed a lot and enjoyed my suffering. He’s been there himself and was living proof that it is possible to come out the other side with a beautiful green building.

Today we started clearing the site and I can see some real, albeit, surface changes taking place on site.

Sunday 4th of June

Today I ‘volunteered’ on Piers strawdio site, as part of his rendering weekend. It was great fun to do and I remembered what is go great about volunteering on straw bale builds – the people are so varied and interesting. I was encouraged by the level of commitment everyone was showing.

Sunday 21st of May

Turns out it wasn’t a Lime but a Pocket Handkerchief tree. At first I thought it might be rare, but I found a site that sells them for £30 on the net, so they can’t be that rare. I feel less bad about cutting down a Chinese ornamental tree than a Lime, but I’ll keep my promise to the tree to replant the same kind.

I have wounded both legs. One has a torn muscle and the other has great bruises. Site safety, site safety - my new mantra. Also walk – don’t run.

Saturday 20th of May

My eco-vegetarian-hippy conscience could barely take the strain today of having to cut down a beautiful and perfectly healthy Lime tree. It had put on a beautiful display of blossom, all to no avail. The chain saw won. Then I fell down one of the test holes.

Friday 19th of May

Terrible rain as we lay concrete foundations for the small retaining wall between us and the neighbours garden. This is a warm up project, a way of discovering some of the issues of working on the site, setting up relationships with suppliers, making sure we have all the tools. Its also a way of getting me used to project management, site safety and so on. Today was a real test and a trial. Not only did it rain all day, but I pulled a muscle in my leg by being over enthusiastic and in too much of a hurry. I could barely walk, but we ploughed on mixing and pouring until the job was done. Over night the tarps covering the footings filled with water and distorted the shape of the drying cement.

Yes, that’s right cement and concrete blocks. I thought I’d so a small side project with cement and blocks so that I could see how working with these conventional materials compares with all the other wacko materials. So far so miserable, but would it have been any less miserable if I’d bought old railway sleepers and tried to move them around in the rain? I’m not dogmatic about all this low energy stuff, rather I want to use it as a defining design criterion.

Looking down the garden to where the new building will be.
Thursday 18th of May

Mischa and George from the Low Carbon Network came to look at the site. Up to now I haven’t been 100% convinced about using tyres to build the internal retaining walls. These guys are very reassuring. The obvious way to make a retaining wall is to use concrete blocks, but these use a great deal of energy to make and transport, plus if the house were ever demolished they represent a waste problem. Tyres are an attractive alternative because they are a waste material and diverting them into a wall for a few hundred years is a very energy efficient reuse. But, as with all the calculations around energy in building construction, the equation is not that simple.

To build the house I have to excavate about 50m3 of earth approximately 50% of which is clay. The topsoil is inappropriate for ramming into the tyres and clay should not be used on its own (it’s too sticky and it contracts too much as it dries) so it needs mixing with something else. Probably we will use concrete waste, ie concrete from a demolition somewhere. While this still represents a waste problem if the house is ever demolished, it is recycled waste rather than waste that has been created by the building of the house. Like the tyres it is diverted waste. I hope to source this as close as I can to reduce energy involved in transportation.

Rammed earth tyres get their strength from the ramming. This consolidates the material. In conventional building this is done by adding concrete – which literally makes the material solid. Rammed earth tyres use human energy rather than hydrocarbon energy.

Up to 40 minutes per tyre!!!! And were talking up to 180 tyres!

Human energy in western society has been replaced with hydrocarbon energy since the industrial revolution, so I wonder if this building method is entirely appropriate for the 21st century in the west. I intend to find out. I’ll tell you after 60 hours ramming.

George and Mischa say it’s entirely do-able if we can get enough people to help. We are planning to learn as you ram courses and have set the date as 8th July.

Friday 12th of May

We had a barbeque and bonfire to launch the project with a ceremonial demolition. I though a few people would symbolically knock out a couple of bricks, but everyone was overtaken with a fervour and they demolished the entire remaining greenhouse. Alcohol and sledge hammers do mix after all.

Thursday 4th of May

The work begins. My two hunky young volunteers did a short day of digging by way of introduction to the world of labouring. They dug test pits in each corner of what will be the ‘Green House’. We found 500mm of topsoil and then pure clay. I have extracted some for testing to see if it can be used as render on the finished building.

My dominant design criteria are: 1, to use as many materials from the site, 2, to use the most energy efficient resources and, 3, to take as little away from the site as possible.