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Deviant Design! - Forno Bravo Forum: The Wood-Fired Oven Community


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Deviant Design!

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  • Deviant Design!

    I started my brick oven a couple of weeks ago based on the Pompeii plans. It's being built at what some people in the UK euphemistically call a "holiday home" in the English Lake District. Some of us call them "static caravans" and in the US will be known as a "trailer".

    It will be an igloo with an internal diameter of 1000mm (39.4?). From the outset, for what use it will have, it has been designed to be light in weight and quick to fire up. After consulting an eminent oven builder here in the UK I?ve decided it will be made from 75mm (3?) long refractory bricks with a cooking floor of refractory tiles 50mm (2?) thick. The insulation layer will be 150mm (6?) of Insulfrax type blanket with a 50mm (2?) outer weatherproof shell.

    The whole lot will sit on 150mm (6?) of insulating concrete made from 1 part by volume Portland Cement with 5 parts Perlite. An air entraining agent was included as recommended by the Perlite Institute in their application data for Perlite insulating concretes. I understand that this has the effect of introducing minute air bubbles into the mix which (a) Increases the volume (which it certainly did!) and (b) increases the insulation effect.

    As far as the stand for the oven is concerned I?ve deliberately deviated from the Forno Bravo hearth recommendations of a massive slab of concrete, stuffed full of rebar, all resting on massive concrete building blocks, also stuffed full of rebar! As I don?t live in an earthquake zone, or building something the size of the Empire State Building, all I?ve used is 100mm (4?) thick concrete blocks overlaid with 50mm (2?) concrete paving slabs. These are supplied in the UK in 900mm x 600mm ( 36? x 24?) or 600mm x 600mm (24? x 24?) sizes. They are usually used for paving driveways, supporting the weight of cars and small trucks, so they should be more than adequate in supporting my oven.

    Once the block work was completed and set, the slabs were laid and the insulating concrete poured all in a day?s work!

    I?m now ready to build the oven and itching to get going. Unfortunately I have to go overseas for a couple of weeks so won?t be able to continue until the middle of May.

    I've attached a photo of the oven stand just before the insulating concrete was poured. The cooking floor and landing will be 1100mm (43") from floor level and the two side arms approximately 900mm (35") high. The left arm is useless as a storage area because the stone wall intrudes into it but the right one will be used as a log store. The two centre openings will have lockable doors and will be used for storing garden items, peels etc. I'll also store the flue in there when necessary. All the exposed block work will be faced with local stone to blend in with the existing stone walls and the side arms tiled. You can see one of the tiles at the bottom left of the picture.

    Questions or comments, adverse or otherwise, are invited!

  • #2
    Re: Deviant Design!

    Nev Grady,

    You are well on track to be cooking in the oven by June, maybe July?

    This plan looks great and you have covered the important details with good choices. Good mass with the refractory materials you have chosen, and you have selected good insulation all around... the oven should perform fantastic!

    Keep us posted with pictures of your progress!



    • #3
      Re: Deviant Design!

      Looks great! I love the stone walls and really like the idea of blending the base in with them.

      It'll be interesting to see how the stand made of pavers holds up with an oven on top. No criticism intended - all I know about building I learnt here, so when they said build it with lots of rebar I did... I'm sure we'll have lots of builders following your method once you show that it works.
      "Building a Brick oven is the most fun anyone can have by themselves." (Terry Pratchett... slightly amended)



      • #4
        Re: Deviant Design!

        Thanks Jed and Frances for your supportive comments! I realise that I'm possibly sticking my neck out in designing the stand this way but according to structural engineers and the eminent oven builder I've discussed it with, and given the weight of the oven, there is no reason why it won't work.......however there is always Murphy's Law to take into account! (Murphy's Law:- If anything can go wrong, it will!)