Lower ground floor court yard

[HenrikK]

I'm grateful for all advice. Part of the conditions for this build is that I promised my wife that things would look exactly the same afterwards, and that there are some beautiful old trees so I don't dare to make the hole in the ground too large.

I'm basically testing. If the perlcrete slab doesn't set, I would have to remove it and give up the ideas of insulating properties in the shell but just go for waterproof concrete and then insulate from the inside

[david s]

There will be no problem with the vermicrete setting. The problem will be eliminating the free water in the mix after it has set. The garden moisture meter will tell you when it is dry. When it flashes red you know it is dry enough.This post shows it’s use on insulation over the dome, but the same applies for under floor insulation.

https://community.fornobravo.com/for...695#post397695

[HenrikK]

Great advice, thanks. Yes, indeed, it's starting to set, 36 hours after pour. But, you're right that drying out will be difficult. Maybe I'll fining the box and then make makeshift insulated lid and put a heater in it to dry it out.

[UtahBeehiver]

After reviewing the pics again, I see what you are trying to accomplish. How are you going to install a chimney vent with this design if you need to replace the tiles back to original with the existing wall limiting your oven opening depth?

[HenrikK]

Hi Russell,

I'll put up a photo later that shows this better. To the right there is 2 metre wall to the next garden. The thick stone slab on theto of the lower wall through which the opening of the oven would sit ends to the right about 7-8 inches before the 2 metre wall. My thinking is to make the first bit of the chimney inside the lower wall ending centre between it and the higher wall. There I would put a 3 metre stainless pipe. Even if this gives quite a narrow chimney, the lenght should ensure a good flow.

Henrik

[david s]

What size oven are you building Henrik?
For hemispherical ovens the following is a guide for oven flue diameter. For other oven types work on equivalent oven.volumes and for square or rectangular flues work on the same cross sectional area as the round flues.

up to 24" diam use 5" flue

24"- 39" use 6" flue

39+" use 8" flue

[HenrikK]

Hi David,

I think it would be something like 28 inches and the flue pipe 133 mm so 5,5 inches. As lenght of chimney increases flow, what were the lenght used for those recommendations?

Cheers

[david s]

That should be plenty, assuming your oven is to be a 28” diameter hemisphere. The cross sectional area of the flue is more important and powerful than the height in increasing the draw. The average height of most oven flues is around a metre.

[HenrikK]

I'll put up a full report soon, but here's a teaser: pizza with pancetta, talegio and raddichio cooked in my oven