4. The Dome Sand-former and First (Oven) Layer

Finally it is time to start building your oven. For this stage you’ll need:

  • Builders sand
  • Old newspapers
  • Water
  • Tape measure or long steel ruler
  • Clay-sand mixture

You are going to build a large sand dome – the former which supports the first clay-sand layer of your oven. I really enjoyed this part of the process mainly because it provided a practical justification for the hours I spent building sandcastles on the beach with my stepson Thom when he was a little lad (to be fair it was usually me who wanted to build the sandcastles!).

Sand dome partly covered with wet newspaper.

Sand dome partly covered with wet newspaper.

Tip lots of sand onto the brick floor of your oven.  I’m not sure how many bags I used but I remember being amazed at how much was needed to build up the dome to the required dimensions.  Remeber the outside of this dome will form the inside dimensions of your finished oven.  The base (widest part) of my oven is the same dimensions as the length and width of the brick floor (80x80cm).  I decided to make the height of my oven approximately half that of the diameter (40-45cm). Build up the dome, moulding and sculpting with your hands until it is the desired height and a nice shape.  A top tip from Steve at River Cottage HQ is to keep checking the shape of the dome from above, so periodically stand on your plinth to get that birds-eye view! Once you are happy with the shape, firm-down the sand with your hands.

Sand former covered with newspaper

Sand former covered with newspaper

Next you need to add a layer of wet newspaper.  This makes removal of the sand from inside the cavity much easier later on.  It is a little tricky to get the paper to stick but persevere and you’ll crack it.  Thats the dome complete. Now you are ready for your first oven layer.

The First (Oven) Layer

If you are doing this alone make sure you leave 3 or 4 hours to build your first oven layer.  I made the mistake of starting in the early evening and ended up finishing it at midnight wearing a head-torch!

Take some of the clay-sand mixture from your wheelbarrow in cupped hands and form it into an elongated/rounded brick shape.  Press this first “brick” against the  base of the dome and compress it into place, with one hand holding it against the sand former while the other makes a “karate-chop” type movement (using a straight hand) against the “domeward” side of the brick. This creates a wedge-shaped “brick” (sloping towards the dome) which helps when adding layers above and also removes any air bubbles from the mixture which may subsequently expand and crack the oven. You are aiming for an oven layer that is approximately 7cm thick and the simplest way to keep check of this is to measure the bricks periodically against a marked stick or even a piece of straw.  Add another “brick” next to the previous one and, using the same technique, mold it into the first.  Repeat the process until you have laid “bricks” around the whole circumference of the dome.

First few "bricks" of clay-sand oven layer.

First few "brick" layers.

Begin laying “bricks” on top of this first layer and continue, round and round, up and up, until you have completely covered the sand dome former.  Remember to keep checking the oven layer thickness as you go. Don’t worry if you end up with some variation in thickness – as you build the oven layer up you might find that the base widens out a little from the weight of “bricks” above.  Smooth and shape the oven layer into a neat, coherent shape and don’t forget to check from above.

That’s it!  Your first layer is complete.  You need to leave it to dry for a few hours before you cut the hole for the oven entrance – which I’ll discuss next.

The oven layer is complete!

The oven layer is complete!

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33 thoughts on “4. The Dome Sand-former and First (Oven) Layer

  1. I may be totally mad but I have started my clay oven in this very wet (but warm) period…I have the first layer in place… I’ve covered it, it is well ventilated..the dome is holding i.e.. it has not slumped…however it is still very moist and soft! I am nervous about cutting the entrance and removing the sand mould. How long should I/can I leave this before proceeding?
    I note you have suggested one can do the insulation layer before removing the sand interior and ?before cutting the entrance? Would the extra weight be too much before the first firing?

    Thank you and thank you for the detailed instructions and all the helpful comments

    Regards Stephen…from a very wet Lancaster 02/12/15

  2. I may be totally mad but I have started my clay oven in this very wet period…I have the first layer in place… I’ve covered it with ventilation…the dome is holding i.e.. it has not slumped…however it is still very wet! I am nervous about cutting the entrance and removing the mould sand. How long should I/can I leave this before proceeding?
    I note you have suggested one can do the insulation layer before removing the sand interior and ?before cutting the entrance? Would the extra weight be too much before the first firing.
    Thank you and thank you for the detailed instructions and all the helpful comments

    Regards Stephen…from a very wet Lancaster 02/12/15

  3. Hi Simone,
    Is it possible to use just clay for the oven?
    Or to use stone work to make the dome and fill it in with clay?
    Currently in Japan making it for my host, it’s good smooth clay and it’s white thick stone I’ll be using.
    Any recommendations?
    Thanks heaps

  4. My son and I put constructed first layer of clay/sand mix yesterday. We puddled the mixture and it didn’t seem too wet or too dry, however, I have woken up this morning and realised that I probably used a ratio of 1 clay to 4 sand rather than 1:2. DUH! (It is holding together fine, no slippage, but is still fairly damp) Is this going to be a major problem? Cheers Pippa

      • Thank you for your reply. I think I will leave it to be well and truly dry before we take the sand out…fingers crossed. Thank you for your great site.

  5. Hi Simon did the lime drop test and although it seemed wet the mixture held it didn’t splat or crumble apart although trying to keep it from getting any more wet in this weather is proving to be a task tarpaulin on tarpaulin off nightmare finished the first layer yesterday and it’s looking good just waiting to cut the opening today it’s not drying out as quick as I’d like because of the weather thanks for the advice I’m sure I’ve got more to ask as I’m progressing cheer

  6. Hi just done my first layer after straining my liquefied clay and hanging out to dry in sheets producing a nice stone free clean clay however after puddling my 3 batches I realised I’d used sharp sand instead of building sand is this going to be a problem?

    Cheers

    • Hi Darriel

      it won’t be a problem at all! It’s all about the consistency of the mix. Make sure it is not too wet or too dry, or that there is too much, or too little clay content. It needs to be in the “Golidilocks Zone”, i.e. just right!

      Have fun building.

      Simon

  7. i have nearly finished building my oven,as i live in Ireland origionaly from scotland,me mammy always told me to put on a number of thin layers to keep warm. for my insulation layer i made a clay slip mixed with wood shavings,but kept it quite yhogurt like and put on three or four thin layers,letting each one dry not quite solid but tacky. i let this dry solid, then i applied a thicker mix of the same ( the over coat ) being in country that has changeable weather and hoping to build an oven that could cope with the conditions i thought this might improve my chances it seems to be working. i have a very solid structure. it took time & patience but was worth it.

  8. Hi,
    your pizza oven looks great ! I’m also making one using the river cottage bread book but I’m having a lot of problems with this layer. I’m about to make it for the third time .The first time i know what the problem was but the second time i’m not really sure whats happened and was wondering if you could help.
    I did everything per book instructions but left if for 3 days to dry as it’s in the shade and dug out the sand yesterday and when to check that there was no cracks before lighting the fire and there was about a 2″ wide crack running up the back !!!
    Why would this of happened ?
    Thanks,
    Lili

    • Hi Lili

      what mixture (i.e. proportions) are you using to build the layer? Also where are you based? It is either a mixture problem or a weather problem I think. The longer you can leave it to dry naturally the better (lighting a fire in the oven while it still retains a significant amount of moisture will cause cracking). You could try making sure the fire is very low, gentle heat, which will dry the layer over a longer period of time. Other blog posters have suggested covering the oven layer with a damp blanket (or sack). This also slows the drying process and prevents cracking. Cold, hot or damp weather will also effect drying times. Another thing you might want to try is moving on with the process, adding the insulation layer before you remove the sand former.

      Let me know how it goes and please drop by with other questions should you have any.

      Simon

      • Hi Simon thanks for the reply 🙂 I’m in Australia so it’s summer here and averages about 23degrees c. I’m using 2 buckets builders sand to 1 bucket potters clay. I’m thinking its a weather problem too. I’ll let you know how this third try goes 🙂

      • 23 degrees C!! I’m very jealous as I’m sat at home in a very wet and very cold, wintery UK. Well it should dry well in your climate but maybe it’s drying too fast? Try wet cover technique to slow the drying time. The quantities of your mix is spot on.

        Let me know how you go.

        Simon

  9. Hi,

    Great Blog, Just a quick tip for the newspaper. well 2 actual.

    1. Wet individual sheets, don’t be dumb like me and wet the whole paper. It becomes a total mess and impossible to separate in to sheets with out ripping.

    2. it is difficult to get the sheets of paper to stick, start with a double page hung over the top of the dome bit like a hat. Then other sheets stick to this r quite well, then just work your way around the dome to the bottom.

    Clay layer goes on mine tomorrow!

    bye

    Jamie

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