I trained as a pizzaioli in Naples, it was something I always wanted to do, but as a Grandad, most people didn’t really understand as they were there for their careers, with me it was a passion. Yes, I did think of a career and even converted a lovely old 1970’s French H van into a mobile Pizza Oven. But I settled on building my own in the garden, which isn’t as mad as it sounds, hard work yes, expensive no. The result became a major part of our foody lives, not just cooking pizzas at over 500 degree C, but long slow cooks, using the ovens residual heat Ribs, Meats, baking breads. the results were incredible.

Here’s how we did it.

Wood fired clay pizza oven

I was always fascinated by those big wood fired pizza ovens id occassionly see on holiday in italy or france and always enjoyed the results, slightly charred thin crispy pizzas a million miles away from the rubbish that any supermarket and large chain restaurants could offer.

As I got older and acquired more DIY skills, mainly through buy old houses that needed the work and a desire not to have to pay tradesmen to do simple jobs for me, my projects became larger and larger, never really having the room was a factor, but in 2009 we finally acquired a house that had the necessary space and I had the required DIY skills, so a pizza, or clay oven was on the cards, so to speak.

So, as I always do, I set about the task of learning about the ovens and what the best type were. I thought an easy fix might be to buy one but at around £1000.00 for a simple one, I thought again. I’d seen some elaborate ones that were costing around £30,000.00 ( see Jamie oliver ) and suppliers such as fornobravo and vitcas can supply you kits, but not only are the expensive, so still have build bases and support for them and I still believed I can do better for less so bring it on I thought, I started looking

I was quickly led, thanks to Mr Google and his amazing searches to earth ovens. A primitive form of oven essential used by nomadic tribes in Africa for many hundreds if not thousands of years, to bake bread and other food.

In their simplest form a mud oven, fired and used as long as they were at their current location, then basically left as they did. Because these things were clay, they returned themselves to nature, for as soon as any rain came along they simply melted. A nice idea, to build something from the earth and return it simply and sustainably.

One name keep popping up - Kiko Denzer http://www.amazon.ca/Build-Your-Own-Earth-Oven/dp/096798467X

– and a book , how to build your own earth oven. Now there are loads of blogs, like this, guides, books and information available online, some good, some not so, but the best all use the guidance of Kiko and the book, so I decided to also.

Its an interesting read talking about the history of the ovens and their useages with examples of them from all over the world, some good, some just awful. The really interesting parts are the science of them, for if you get the angles, arches and door openings wrong, they simply dont work.

Considerations as the type of clay, its mix, it locations and the pure weight of the ting have to be considered, so The task began, by far the biggest DIY project I had undertaken as will be revealed.

Location

Obviously, I wasn’t going to build something that wasn’t pretty so to speak and I would be a centre piece in the garden outdoor area, so it would need to be located where it is practical to use. Clearly everyone’s location will be different, but these things throw out a huge amount of heat from door entrance, so keep it well away from anything flammable. They also weigh about a million tonnes, so think about a suitable base to with stand that.

Id seen a few designs that I was tempted into, using railway slippers to for a base, to be honest they looked ugly, so I dismissed them. I then saw a very pretty brick base, built rather like the brick bases for BBQ’s, but it was also not so pretty and my skills at bricklaying are ok, but it was fairly complex and as my time was limited to just weekends, it might take months and I was getting itchy for my fist pizza now. I saw a very very pretty concrete block and render base that looked just perfect but wasn’t man enough to take the weight of the clay, so I had to adapt the design to do so.

I started with the area I had and the intended size of the finished oven, this gave me a starting point forth base which I constructed from Concrete blocks 440 x 215 x 140 as these were readily available pretty much anywhere.

First thing was footings, so make sure you have good solid footings of ground to build on. If you built this onto anything without any footings it will subside at least, or collapse at worse, the whole thing needs to have a very very solid foundation.

My Base was to measure around 120 x 120 cms, but didn’t have to be deadly accurate as long as it fitted in the area I had as the clay oven going on top of it could be adjusted as would be required. It was important that the oven be large enough to take a pizza, or indeed anything else I wanted to pop in there and this directly related to eh size of the door or entrance, so I figured wider than an average baking tray would be right.

Working height is also important, about kitchen worktop height is good, bearing in mind that you should work backwards or downwards, as there has to be other layers of not just concrete blocks, but support, insulation and fire bricks for the floor of the oven.

So we worked out about three courses of blocks would work. This was built with an opening at the base, so effectively making it hollow, for wood storage, again making it look prettier than most. This raised another issue, that of strength as id estimated the oven and supports might weigh in excess of 500 kgs, probably more and I didn’t want it to collapse or even subside, so at the third course we finished nice and level and added concrete lintels across the width, having first worked out we could get them to the same size to avoid having to cut them.

One of the lintels was across the front opening ( woodstore ) for support, we used three in total.

On top of these we laid some fireproof fibre board, quite thick, around 150mm across to give us a base for the next level up.

Then another round of bricks to give us a kind of well, this was to contain the next level. That was it effectively our base was finished, apart for a nice render coat, which I have to admit was done by a contractor for us.

Heat retention in these ovens is essential if you are to use it to cook long and slow, many inferior ovens do not have that heat retention and are ok for pizzas, but there it stops, they go cold in a matter of hours. Good Heat retention means good insulation, and this, in our case takes the form of empty wine bottles, something you find with ease in the Jennings home :-)

So on top of the fibre board base we laid some sand, into the sand we planted bottles, empty bottles. The idea is that these work like double glazing and hold any heat about and stop it getting too far below, as we all know heat rises so less important below but very important upstairs, so to speak.

We then back filled any empty gaps with sand, making it nice and level

At this point you could go the route of a layer of concrete paving slabs to give you a nice level base for the next step that being the floor of the oven. We decided that as the oven already weighed several million tonnes, that a finishing layer of clay on top of the bottle riddled sand would suffice, the clay I will come to in a moment, as wede worked out, as good physics tells us, that the weight of the dome to be build would be transferred mainly around the outside of the oven, down through the walls and there need be any real rigid strength in the centre.

The Floor

The floor simply had to be made of heat retaining bricks, not fire bricks, a mistake I made at first, but bricks containing alumina, which helps heat retention was, after my research, the way to go so I found some at http://kilnlinings.co.uk/firebricks

I needed 16 I had calculated and didnt want to have to cut them, as I could build the oven on top and around the floor, to hide up the edges.

I had omitted to mention that I had laid the bricks in still tacky clay, to give the bonding that would hold them all level and straight as they dried. Level is critical, or at least no bricks uneven as when you eventually, hopefully start push pizzas, trays or Tuscan grills ( see later ) any raised edges will stop the items being placed in or pulled of the oven, which at 700 degrees and hotter, will not be easy or appreciated.

Clay

This is a bit of a black art , very well described in the kiko denzer book, which I highly recommend you buy.

I had investigated lots of different ways from the river cottage way, going to a river or pond and digging it out yourself – just try moving a barrow load of wet clay, let alone getting it out of the ground and see what its like – digging it from the ground, if you live in a clay area which we do, fine, but it will be riddled with odd stones and youll have to remove. You can buy small bags of craft type clay used for pot making, but still not really suitable. After a lot of searching I finally found a company who would deliver 1 tonne bags, sounds a lot but it isn’t. for a sensible price – I think about £80.00, which is more than would cost you as in theory its free, but trust me, it’s the real deal and I figured theres every chance I can sell it on ( thanks to e bay ) to other oven builders ( which I did ) , any that I didnt use.

Called puddling clay its whats used in making canals, lining river beds and garden ponds as it allowing puddles to form. Is it is of course perfect for clay ovens, getting it was the easy part, then came, what is also known as poddling the clay.

You cant use this clay on its own, that would work, it has to be mixed with sand to the right consistency, this comes about, as we did it, but there are other ways, a children small paddling pool would be idea, but don’t put the kids in afterwards, it will get ruined.

We placed a plastic sheet on the ground and held it in place with bricks ( see picture ) you then place a bucketful, a handful at a time the size of an orange on to sheet, along with a similar amount of sand, then a spot of water, then with or without wellies, you ‘poddle‘ the clay with you feet. The idea is that you push the clay into the sand mixing it to the desired consistency adding water if it become too dry. You looking for a firm but not runny mix that if you formed into a sausage size and held at the top, would drop slowly or take a piece and drop it in the floor, it wont splatter, itll drop into a round firm form and flatten slighty as it hits the ground.

You may think that you can mix it in a cement mixer, but it dosent work as this pulls the mix apart, as opposed to pushing it together which poddling does.

You looking to be able to form ‘cobs’ so called as the age old building technique in medieval times of building cob houses before bricks were widely available and clay was plentiful. A lot of these houses still stand today many hundreds of years after being built.

Now a cob , is a piece of clay made into a large sausage shape that you use to build the dome of the oven, but first you must decide what to build it around as a dome will need some support as you form it. We used sand, some people have made elaborate wooden structures, some inflatable balls, as you have to consider whatever you form it around, you have to get out once the dome is formed.

So you care with some damp sand built a sandcastle to the desired shape and inside size of your clay oven wall. I made ours the size to cover the floor diameter, so as not to have any gaps once the dome was formed and the sand removed. This is then lined with, damp newspaper to stop the clay sticking to the sand and ruining the shape as you build it. Once you’ve formed your dome you are ready to start building the first of many layers ( up to three or four ) of the clay cobs.

These are placed along the outside edge of the sand form, then the next one, eventually working your way right around the diameter, when you get back to where you started you jump up a level, all the way up until you reach the top and the first layer is formed.

Its very important that you dont push into the sand as you build as this will compromise the dome interior shape and may give problems later on, push down on the cob level below as you go up.

First layer complete, stand back, open a beer and enjoy the fruits of you labour, this is real mans work, earthy, outdoors and there no better felling with the sun on you back sipping a bottle of cold suds.. sorry wrong film 

Now leave it, cover it , ideally overnight, keep it dry, any rain will be a disaster it will just disappear, it is clay after all.

Next day, the most nail biting part, well almost, removing the sand – drum roll!

Before you do the real job you can practice with a small or muffin oven as they are called, small enough to bake a muffin in ( see picture ) this will give you a good feel as to what to expect and you can fire it up and see what happens.

With the clay firm but not dry, cut you door way, now this has to be to be 63% of the interior height of the oven using an old knife cut you way through to the sand, removing the door section, saving it for more poddling. Reach in and slowly pull out the sand, if you are lucky and you’ve built it as mentioned here and in kikos book, the dome should be self-supporting and hopefully not collapse. If it does collapse its more than likely that one of two things have happened 1. You’ve pushed the cobs into the sand and weakend the shape, or 2. Youve used to wet a mix. In which case its time to start again.

Ours, thankfully did stay up, so now we light a very small fire inside it to dry it out a little, which will give it strength, to then build up the next layer until you have the desired shape and size.

Some people have built up two layers of cobs and left it, but this may be too heavy and cause collapse and if it dries too much may prove difficult to cut door opening.

Before you build up the out layers, youll need to think about what type of opening you want to have, bearing in mind this is the business end and youll be pushing metal trays and pizza peels in , so it have to be tough, brick are best.

We choose a brick arch which was very easy. First of all I made a form our of wood to support the arch, placing the form in place and the brick around the outside, building a wall, using poddled clay mix as the mortar in between until the top where I planted some key stones that lock it all in place.

I then slid the beast into opening of the oven, and filled in the gaps between the oven entrance and the dome with clay, making a sort of tunnel, this I then built up, around and over as I built successive layers of the cob around the dome.

At this time I had decided that a chimney between the brick arch and dome would be useful and as was recommended in several guides, but this proved to be problematical and potentially very expensive as I intended to cover it with a wooden gazebo with a wooden tiled roof, the insulated chimney system would run into many hundreds of pound and as it happens, wasn’t required and worked perfectly without one.

So there I was the oven had an entrance that looked great, two layers of cob, with one or two more planned, and I m gagging to have a ‘burn up’ as we refer to them and get a pizza cooked to perfection, my very first pizza. As you can see from the picture the very first one, albeit trial and error was a success and tasted great. I sat back and felt great.

Next morning – disaster as a result of my over engineering and anal attention to insulation detail, it had retained its heat so well, large cracks appeared, some up to one inch wide, all over the dome, it looked like the surface of a dying planet from one of the star trek or space disaster ak movies, fortunately it was the second layer and not the interior or first, which was intact, I guess id not waiting long enough ( about two days ) for the whole thing to dry out fully before having a full burn up, which probably, I know now, generated about 750 degrees of heat.

Id already read that any cracks that appear can be simply filled in and you then carry on, so with that in mind, I did just that, after letting it all cool down and carried on with the next layer, completing the final dome shape which I built around the arch brick entrance to give a very pleasing and good looking oven.

A few finishing touches, like mosaic tile around the base to finish off and I had a very nice looking piece of kit indeed.

The thoughts came to keeping it looking that way and the fact that it was made of clay, one long rain shower and it would be history, so with summer ticking on the race was on.

The temporary cover I built was a waste of time, to cumbersome and just ugly, so I set about incorporating the oven into an outdoor kitchen, complete with work surfaces, work and storage areas, a cover and lighting, that another project ( see outdoor kitchen) Needless to say I still wanted to have a nice finished that would protect it from our harsh, cold wet English summers  again I did a whole load of research and although someone had suggested a waterproof render, but as this was made of clay and had to breath, a render would cause moisture build up inside and would invariably cause an interior collapse. The solution I found was a lime based render used for restoration of historical buildings, which can be difficult to work with as it heats up and can be caustic, but id found a stable one that was ideal, so mixing and applying it was easy, a couple of layers of around ¼ to ½ each and a nice smooth trowel, gives a finish that can be if you want, painted, Lovely!

The story of the oven dosent finish there and its giving lots of great pizzas and other dishes you would not have thought of, so check out the other sections and links and enjoy.