Benjamin Dinkel

Hi Annie,
I think you'll be able to build a RMH with the bricks you have.

But in order to help you find the right one, please explain a bit what use it's going to have.
A rocket stove is used for cooking.
You mention heating a greenhouse and a water jacket?
For a water jacket you need high exhaust temperatures, a RMH doesn't provide that as the heat stays in the mass.
In a greenhouse you might want to build a batch box that doesn't require feeding wood every 15-30 minutes.

Will you be adding the insulation afterwards from underneath? Or will it become part of the floor?

I could imagine spanning the 16” with some type of rougher board (not planed, we get stuff here meant for cement casing) that might be cheaper to get. And then add your finished flooring on top.

Thanks for the input.
I really wanted to use the inclined fire bricks but thought it wouldn’t work on shorty because they would be in the way of the exiting exhaust out of the riser, wouldn’t they?
Do you remember the reason for not using the shelves in a permanent build?

Hey Mat.
So I’m guessing you have beams as a base?
The necessary thickness would depend on the distance of the beams. Also some insulation would be beneficial depending on your climate and the construction.

Here (dry, warm, southern Spain) we often build on the earth. In that case we like to use gravel, then a slab of limecrete with fiber, then whatever finished floor. Tiles or wooden floor.

Hi Mike,
what about a recycled old shower pan? Or bathtub?

I would highly discourage anyone from using tadelakt or polished plaster in horizontal areas where water remains for extended periods. Also a floor is subject to abrasion. It can potentially work with constant upkeep but it’s not user friendly.

I agree with Thomas and Kevin.
An option could be to insulate the jacket itself and the flue pipe.

Thank you Daniel for your insight.

Sure, the necessary air channels would be built into the frame of the door. And the whole door and frame unit would be leaning against the core. I hope it will be airtight enough. I’ll see what I can come up with.

Good news that you’ve built BBRs with just cob as framing. Do you have experience with the shorty too?

And a new question: did anyone try refractory shelves (kiln shelves) for the roof of the burn chamber of the shorty? Most I’ve seen are self cast refractory.

Thanks in advance

Hi Carla, a nice thought experiment. But I think the downsides are immense. Specifically the necessary handling and drying of the material prior to incineration.
What are the arguments again using a Jenkins style dry toilet with hot composting using a couple of buckets? That way you can always have an empty bucket in the middle of the night or when you’re sick. With minimal interaction and a great end product.

There’s definitely a maximum of pressure loss (that translates to a maximum length of pipe and number of turns). But it depends also on what rocket you want to build.