Building with Cob

[benjamin.oneill]

Has anyone had any experience in building with cob? I stumbled on a book about it in Waterstones the other day and have just spent a while looking at what google came up with. Looks like fun!

It remings me a bit of that chap who built his house (in the ashdown forest I think) on grand design, the A-frame and straw bale one. Prior to that he'd been sleeping out under an open platform! Most bushy build site I've ever seen!

Some of the stuff is pretty "zen-heavy", but it does seem a fast, sustainable and very cheap answere to some needs.. Also, the ovens look really handy.

Ben

some of the better sites I've found so far:

http://www.kleiwerks.com/

http://www.cobworks.com/

http://weblife.org/cob/ - cob builders handbook online

http://www.alternatives.com/cob-building/22.html

Lots of good ones, just watch out for crazy hippies they bite (if you smell like muesli and mixed pulses)

 

[KIMBOKO]

I live in Suffolk and we have an equivalent to cob walling usually refered to as clay lump. Below the top soil in the heavy clay areas there is the ideal subsoil to make clay lump bricks. These are then dried and turned until fully dry then used as bricks with a clay and lime mortar and a lime, clay and straw render. They tend to be a lot bigger than fired bricks. This method of construction was very popular here in Suffolk in the early 1800`s as there was so little wood left to build timber framed building or to burn bricks. It was a cheap and quick method of constructed which was required as there was a population boom at that time. There are also some cobwalled houses and walls apparently made in a similar way to the Devon and Cornish cob houses with shuttering and lots of thumping. The "Bushcraft" book by Richard Graves also mentions it. There is another use of soil for building that I have heard of, usually, with a small quantity of cement or lime mixed in. It involves making a fairly simple but robust mechanical brick maker which compacts loose soil. The device is called a Cinva Ram and details used to be available from the Centre for Alternative Technology .... CAT.
A fried of mine had a clay lump house which had been rendered with an impervious cement render. One day after a lot of rain and wind the whole end wall fell out into the road. No-one was hurt. But it was a bit of a shock. These sorts of materials need to breath and the cement render was stopping the moisture escaping. The rain had also penetrated the render through small cracks and added to the high levels of moisture already in the wall, the clay softened which led to the wall collapsing.

Don't knock the Hippies, if that`s alright with you, man!.

 

[benjamin.oneill]

Hi, thanks for the info, nice to add the history element. For the record, I think hippies rule, I love anyone who has the balls to try and opt out of accepted social norms, we need more of them! On top of that, the values that guide that kind of lifestyle choice are very virtuous. I have had a bone to pick, it would be rhetorical... I can't see how an inanimate object can exude "positive energy" unless its either hot, or plugged into the mains!

I think everyone on this forum, by virtue of being here is driven by a need to opt out to some extent. People who hapilly do the 9 to 5, 2.4 children, suburbian semi and one stop, convenience consumerism are the ones who drive me around the bend! Hats of to anyone who wants to do their own thing!

Ben

 

[Toddy]

Kimboko that's an excellent information full posting on the clay bricks/lump. :You_Rock_ I'm on heavy Lanarkshire Blue Clay and it used to be mined for making the fancy wally tiles that line tenement closes, but I'd never have thought of using it as it is.

Hi Ben, nice links , thank you, another thing to play around with

Cheers,
Toddy

 

[demographic]

If its the same as I think it is, up here it gets called clay dabbing, from what I have heard it's not dead easy to insure clay dabbing houses and they were only built in areas where theres not much stone for building anyway.

It's nothing like as quick to put up as a timber framed house and no more enviromentally friendly, you end up with walls three feet thick and not much light in the house.
Try fitting decent shelves to it

I have worked on one house with a few walls made from clay dabbing and if it wasn't for the fact that it was listed we would have run through it with the digger.

That house on Grand designs with the timber frame and strawbale infill was a far better idea in my book (ben somebody or other?) as it has decent insulation properties and a faster build time.

One other thing is that although houses with nice flowing rounded corners and natural shapes look nice, they are a right pain to fit kitchens,skirtings,doorframes and just about any other square edged item to.

Yes it can be done but I know as a carpenter that it's FAR more expensive to fit them out, anyone with a stone walled barn conversion will know what I am talking about.

The materials are often a lot lesser cost than the labour so unless you plan on doing things yourself it's going to cost a bomb.
How do you get them through our countries well established (and for good reason before anyone starts waffling on about regulations stiffling invention) building regulations?

How do you combat the problems of damp?
I know they are breathable but I have also worked in quite a few barn conversions that are breathable and damp can be a difficult problem to combat in some old buildings without a proper DPC membrane and cavity walls.


Sorry, I am not trying to put a downer on them but I really believe that there are better options out there, timber framing being one of them.

Regards, Oscar the Grouch

 

[benjamin.oneill]

Your points are well noted,

My thinking wasn't so much for the UK anyway, we have so many resouces here its way easier to build better, cheaper, lower impact housing.

On a much more practical note, and good for recyling to, If I did want to build a little house on the cheap I reckon this kind of idea is better:

http://www.escapeartist.com/OREQ4/Nomadic_Housing2000.html

http://www.fabprefab.com/

I live on thick stodgy Wealden clay here, and something like this could work for livestock - my first thoughts when I saw the stuff was what a handy way to build a little pig shed.

For me, I really like the look of the ovens (without the crazy sculptures - personal taste )

Also, I think its applications in other parts of the world important.

 

[KIMBOKO]

I think that it is the small stones, flints and sand in the Suffolk subsoil make it usuable as it is, less shrinkage/greater stability. However any clay soils can be adapted to make a building material with suitable additions. There is a saying about these type of buildings to the effect that you must keep its head and feet dry. So you should use a stone foundation (nowadays I assume a dpm as well) to stop the water rising and have a roof that projects well over the wall. The pretty Devenshire/Cornish cottages of Cobb often have a roof projecting 3 feet over the wall. At that time in Suffolk it was the lack of material and the cost of transport that made the Clay lump attractive. Timber framing these days is very easy with supplies of cut wood coming in from Scotland and the Baltic but at that time each piece of wood may well have had to have been hand cut with a pit saw. Then transported by cart. If the wood supplies weren't local then the Clay lump became very attractive.
Modern timber framing and straw insulation seem like an excellent way of building. There are some "show" buildings at CAT using this techniques with 3 feet thick insulated wall which almost makes body heat and cooking heat the sole heating requirements. A visit to CAT is well worth while for a different way of looking at things.

 

[swyn]

To make mud bricks is not too difficult providing the raw materials are close to hand. Clay,being one of the most important ingredients. If you need to add other materials things such as straw,horse hair, even sand these easily added but not taken away! A bit like the ingredients of a cake, miss out one part and it becomes a sticky mess. Certain areas had the perfect mix right there in the ground in that case they were used as they came. Occasionally lime was added to improve the setting and stability issues. Pise or rammed earth is very much the norm in parts of Bucks and also wherever this type of material could be dug easily.
The mud bricks that we made were from a mould that seems common to quite a few places in the world. This measures the same as a bought building block ie 18"x9"x41/2" although it seems easier to make them 5". The mud mix is churned in whatever way possible (of course we used a cement mixer) but animals can be used to do the same and their poo adds to the mix. This is put into the moulds and placed on straw or newspaper on the flattest area possible and left to dry. The bricks are ready to use after three or four days drying.
They are laid FLAT unlike their cousins (laid on edge) the mortar used to lay them is that which they are made of so very easy there. This forms a wall 9'' thick. The other very important thing about this form of building is that any water destroys the integrity of the bricks consequently a feature of all these structures is that they all have a minimum of 3' overhang at the eaves. They are dry,warm and easily maintained. Similar material being used on the floor over a limestone or chalk base. The raw material came on a lorry from about 10 miles away and was straight from the ground. This was a business solely operating with this type of building method in mind.
Interesting that Demographic thinks that this can be easily run through with a digger..... I was VERY surprised when I tried. They may LOOK flimsy but this is deceiving (sorry Oscar!!!)
The thing with bale building is that you have to have a baler! you have to do this in quick time or rodents get in and I'm not sure that I want 3' thick walls.
Timber framing has to be the best BUT look at ALL the work needed beforehand.
I still think for simple low impact building on a budget mud brick is not easily bettered.
The most recent building that I investigated was built solely using these principals. This was a renovation. The only materials were mud bricks (same mould as above),lime mortar and render etc. The only modern item was the stainless steel wire stitching the water reeds together to form the mats that were attatched to the celings instead of plasterboard. Oh and the tiles on the roof instead of thatch.... but this can also be argued as original This was also an exercise in ALTERNATIVES to the planning regs and in certain areas this was clearly putting said department into a real tizz!
Swyn

 

[demographic]

On a much more practical note, and good for recyling to, If I did want to build a little house on the cheap I reckon this kind of idea is better:

http://www.escapeartist.com/OREQ4/Nomadic_Housing2000.html

You have just stumbled upon my favorite form of buildings, cheap (ish), secure, and can be dropped off the back of a truck with a Hiab.Or if you are that way inclined, moved anywhere in the world onboard a ship.

They can be insulated, plasterboarded, used as toilet blocks, offices, canteens site stores, workshops you name it.

The problems that can occur with them are things like condensation on the inside of the steel causing rust and damp problems but if they are ventilated properly that can be avoided and if they are not properly insulated they can lose a lot of heat when it's cold and get really hot in summer.

Although I have never tried it, it might be better to put one beside trees to keep the sun off it a bit.
I used to work for a company that rented them out to building sites and although it was about the most boring job I have ever had I was however impressed by the ISO containers, one bloke I knew even lived in some of them arranged in kind of a C shape over in Holland.


On your link theres an image of Richard Buckminster Fullers Dymaxion house, there was a man with some potentially world changing ideas.
Some pretty bonkers ones also, his geodesic domes were ahead of their time and if you get a chance it's worth reading his biography.

I have copied a book (I would have bought one but I couldn't get hold of one) about his Patents, he designed an amazing amount of things ane really wanted the world population to work together, Pretty cool bloke in my opinion.

 

[george]

You have just stumbled upon my favorite form of buildings, cheap (ish), secure, and can be dropped off the back of a truck with a Hiab.Or if you are that way inclined, moved anywhere in the world onboard a ship.

They can be insulated, plasterboarded, used as toilet blocks, offices, canteens site stores, workshops you name it.

The problems that can occur with them are things like condensation on the inside of the steel causing rust and damp problems but if they are ventilated properly that can be avoided and if they are not properly insulated they can lose a lot of heat when it's cold and get really hot in summer.

QUOTE]

I'm in the process of building a new house and I really wanted a cellar to store veggies etc. in. However with the bedrock being just under a metre down it was going to prove far too expensive.

We were going to put in a berm on the windward side of the house to shield it from the prevailing wind so I decided that if w excavated a metre deep hole and dropped in a shipping container and then built up the earth on top to cover it up I could kill two birds with one stone - a cellar and a wind shield.

So now I've got a twenty foot container to weld up the doors on and paint with bitumen paint and then cut a new entry high up on the side. the temperature in my cellar will be pretty even year round and it will do double duty shielding the weather gable of the house from the winds we get up here.


George

 

[demographic]

I'm in the process of building a new house and I really wanted a cellar to store veggies etc. in. However with the bedrock being just under a metre down it was going to prove far too expensive.

We were going to put in a berm on the windward side of the house to shield it from the prevailing wind so I decided that if w excavated a metre deep hole and dropped in a shipping container and then built up the earth on top to cover it up I could kill two birds with one stone - a cellar and a wind shield.

So now I've got a twenty foot container to weld up the doors on and paint with bitumen paint and then cut a new entry high up on the side. the temperature in my cellar will be pretty even year round and it will do double duty shielding the weather gable of the house from the winds we get up here.


George

On the shipping containers at the place I worked we used some form of ruberised paint, just applied with a roller (quite a small roller so it could get between the ribbing).I don't have the foggiest notion where the paint was from though

Are you sure you want to have a door thats higher than the floor?
Makes it a right pain to sweep out.

If I were you I would be tempted to put a retaining wall and have some form of cavity between the wall and the container so the container lasts better and if you ever need to replace it (or even to re-paint) you just pull up next to it with a Hiab.
Maybe even put the container on blocks with a bit of DPC underneath.

I confess that I have never been anywhere that has used them underground so it's possible that I am being over cautious here.

At the very least, ensure that the hole has adequate drainage and that the gap between the container and the hole sides are filled with pea gravel so the water can get to the drain, even some mole drainage makes a hell of a difference.
We have used mole drains on the sides of shuttered concrete retaining walls so it's drained, otherwise the water reaches the concrete and builds up behind it.

I admit that as a carpenter, drainage isn't my strong point though so if anyone knows better then I don't mind being put right.

Regards Scott.

 

[george]

Yes we're filling the sides of the cavity with gravel and the base will be drained too. The Container will stand on concrete pads within the hole and will be wrapped in house wrap as well as the bituminised paint - should last me out I hope!

Problem with putting the door at floor level means that it will be below ground level and will be more likely to flood, so although it's a pain it will mean that the door will be slightly above ground level but you will walk down a short set of steps to get to the floor inside.

Sorry to take it off topic - but I promise I'll put a little bit of cob in the retaining wall

George