Heat Loss through edges of cooking floor...

[crowx]

Approaching 5 months in to my build I'm just about done with the brick dome.  

(In my defence it has been almost entirely Saturday mornings at one every three weeks if I'm lucky!)

It's a firebrick dome built on top of a firebrick cooking floor which I laid first.

The cooking floor as laid is not neatly cut in a precise circle, but laid to the closest brick with the herringbone pattern.

This means in some places almost a whole brick directly connected to the cooking surface protrudes outside of the dome area.

Additionally, because my design has the flue and entrance arch OUTSIDE of the door, when the door is closed, the cooking floor effectively extends out under the door in to the uninsulated, unenclosed entrance arch.

Now that Im starting to get set for the insulation (I'm planning cf blanket and vermicrete), I'm wondering how concerned I need to be about the cooking floor conducting heat out of my oven. Do I need to be covering all of the protruding cooking floor with the same insulation level?

What about the way the cooking floor extends out ounder the door in to the entrance arch? Does this cause a big heatloss through thermal conductivity of the fire bricks?

Would love any thoughts from more experienced members..

Here's a picture of the only time I ever in my life used an exercise ball, as thanks in advance....! In the image you can see some of the protruding bricks that I'm talking about.

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[downunderdave]

There's not much you can do about the heat loss through the floor at the entry, although some builders use a "heat break" ie an insulation gap around 10 mm between the oven floor and the entry floor, to reduce conduction a bit. 10 mm is not much, but it's better than two bricks touching. It's probably too late to build that in at this stage so don't worry about it it doesn't make that much difference. Regarding the floor bricks sticking out around the dome, you can cut them off roughly with an angle grinder and diamond tile cutting blade.this will then allow you to cover it more neatly with the blanket.

[crowx]

Thanks downunderdave.

Heat break huh? Makes perfect sense, surprised Ive not come across that before.

Might still be able to do that as the entry floor bricks are easy to move at this stage.

[moonhead]

Got to agree with Dave, I like many others don't have a heat break between the oven floor and entrance. Once you get up to temp to cook pizza the heat your generating will out weigh heat loss through the floor. It hasn't spoilt any pizza party we've had cooking for over 30+.
Rick

[crowx]

Cool. Yeah, my concern though is I'm really hoping to be able to fire it in the evening and do bread bakes / slow roast the next morning.

So I'd rather go the extra yard for insulation if it might be the difference between that working or not. Even so sounds like the loss through the entrance floor will be pretty small.

Might just buy it its own duvet...