7. The Final Layer

The final layer.  The oven is complete!  The final layer. The oven is complete! 

So at last we reach the final layer.  Once the insulation layer is dry you can crack-on and finish your oven.

The last layer uses the exact same technique as the first layer so you should be an expert by now. Using the same proportions, mix a batch of sand and clay together applying the good old puddling technique described earlier.  Again, the amount you need depends on the size of your oven but remember that this last layer will require more than the first layer due to the greater surface area you need to cover.  You will also need some spare mix to extend the chimney (if like me you didn’t make it tall enough first time round!) and to keep for filling cracks.  Make “bricks” as before and gradually build-up the final layer. After you have inserted the last brick, pull-up a chair, open a cold beer and sit back and admire your work.  Well done, your oven is complete!  

Next time I am going to provide some pointers on firing the oven so you can get the best use out of it when cooking. 

Finished oven from the front.

Finished oven from the front.


64 thoughts on “7. The Final Layer

  1. Hi Simon, thanks for such a useful blog! I am thinking about weatherproofing the oven. What do you think about coating the final clay layer with a thin layer of mortar?

    • Hi Thomas

      I have not done this myself, but others have. I have no idea how it reacts to expansion and contraction as a result of heating and cooling, but worth a shot!


  2. Have you tried doing anything decorative, with recycled/broken tiles, to the final layer? Just wondered if that’s something that should be tackled as part of the final layer, or separately once the final layer is dry (and maybe had the oven fired a few times). 🙂

  3. Hi Simon I’m miffed as to why the same areas of the outer layer of my oven keep cracking every time I use the oven any ideas is it normal for the inside to crack ?


  4. Hi Simon oven is completed just got to tart up the base but also systems go to cook me a pizza or a loaf I did try to cover the dome with rock wool insulation before adding the final layer but I think it would of worked if I’d used chicken wire to stop the clay slumping back down to the plinth so started again the removed the insulation all is good now and looking healthy
    . Thank you for all the advice and the step by step instructions great!!!!

  5. (excuse time lapse) … you can use linseed oil as a substitute if you don’t happen to have any cactus juice handy.

    Link to FaceBook photos of as-yet unwaterproofed oven >>

  6. Hi all – thanks to motivation taken partly from this great post, we’re now waiting for our clay oven to dry. With regard to waterproofing te outer layer, we are planning to use “cactus juice” – otherwise known as the sap from the flat “tuna” cactus – called “nopal” in Mexico (genus Opuntia). We have some permaculture friends who say this juice, extracted by cutting up the plant material and leaving it a couple of weeks in a bucket of water to ferment, will waterproof clay/cob structures when mixed with water and used as slip. Others have said that virtually any cactus has the right sort of juice. Others propose blending bits of the cactus with water in a liquidizer to speed up the process if you don’t want to wait the two weeks. As we haven’t actually done this bit yet, this is all theory, but will post again here when we actually do it – in about two weeks when the oven is dry. I live in northern Argentina so may have access to larger quantities of flat Opuntia cactus than someone in Scotland 😉 Many thanks again – Guy

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