Elizabeth Echeverria

I would totally back this movie! My question is that it seems that the willow feeder method is based on sort of storing the poop for a while and the whole thing drying/staying pretty dry while being stored (apologies if I don't fully understand, and all the more reason for the movie, but that's my understanding anyway). So I would really like to know how well this would work in a humid summer climate--the kind of climate where stored poop might stink more and things don't dry out.

thomas rubino wrote:Hi Elizabeth;
I suggest a Batchbox-style Montana masonry heater (RMH)
Depending if you build a single skin or a double skin bell and what size core you use.
You are looking at a rough footprint of 4' x 5' with a weight of 2500# to 5000#.
Not that much extra support would be needed; perhaps two extra soni tubes with a wood or metal cross-beam would be sufficient to beef up the floor joists.

The weight figures are super helpful, thanks! Is this pic something you operate? Have you found it an smooth to run (airflow, backdraft, etc) as bench-style RMH's?

Glenn Littman wrote:Hi Elizabeth, Following on from Thomas' recommendation above to build a batch box RMH... for your floor/foundation I would suggest you pour a concrete pad perhaps 18" wider in all directions than the footprint of your RMH. Making the concrete at least 6" thick so that the concrete is your foundation. You'll need to determine the design of the pad depending on your soil conditions and elevation of the floor above grade so having some form of piers or small diameter Sonotubes that are deeper into the ground for stability may be required. I would then install some insulation around the perimeter of the slab below floor level as well as underneath. This is the principal that I used when building my house area that has in-floor hydronic heat. I hate styrofoam, but 2" thick construction  grade sheets laid underneath and around the perimeter of the on-grade slab help significantly to retain heat in the slab. The slab will then become a part of the heated mass and provide you with a solid foundation from which to build the RMH.

I can tell you from the experience of my 6" BB-RMH system that is built on a 6" thick concrete floor in my shop area that does not have the insulated hydronic floor as noted above... the concrete 18" out from the perimeter of the RMH is roughly 18 deg F warmer than the rest of the floor in the shop. If you were to surround the concrete pad with insulation it will better retain the heat and likely run well more than 20 deg higher than the ambient air and become part of your thermal mass.

That's a good point about the concrete base becoming part of the thermal mass if insulated well from the exterior elements. Our current home has a foam insulated slab for in-floor hydronic heat, and it definitely does a good job. I just wish there was a different option than foam.

Sounds like you have direct experience with a BB-RMH. I've been hesitant with them because I've heard they're more finicky with airflow. Have you found that yours is okay in that regard? Anyone else want to weigh in on the finickiness of BB-RMHs compared to bench-style RMHs?

Cristobal Cristo wrote:Clay bricks (so also firebricks) have much higher embodied energy than concrete.

Did you mention this in relation to my comment about maybe using a masonry heater (lots of brick) instead of a RMH? If so, that’s helpful to think about, thanks. I didn’t consider the embodied energy of the actual masonry heater since it’s made with so many bricks. Another good reason for me to figure out how to support the RMH and go that route…

So here’s the conundrum:

We want to build a small cabin with a low carbon footprint, so we want to avoid a concrete slab (HUGE embodied energy/emissions)

We live where earthen floors get damp and moldy and frost reaches many feet deep in winter. The only attempts I’ve seen near here, even above grade, have failed, so earthen floors seem inappropriate (even though they may be great for drier climates.)

So we are thinking of building a standard wood floor (well insulated) on small poured sonotube footings.

We want a rocket mass heater for the long cold winters…but how to support such a heavy, sprawling thing when we don’t want to use (much) concrete to reinforce the cabin floor, need to be careful with moisture issues, and need to insulate from extreme cold?

Any ideas??

We’re also considering a more upright masonry heater so a poured support wouldn’t need such a big footprint. Then, if we had to resort to concrete, it at least would be less of it.

How have others dealt with this sort of issue?

I had a garden bed roughly 10 feet from a willow  tree that was 10 or 15 feet tall—not sure the kind of willow. The roots totally invaded the raised bed with its rich soil and really stunted any veggies we attempted to grow. That was an actual tree, not a fence, but I’’ll certainly hesitate to grow willow near veggies after that.

Andrés Bernal wrote:

Elizabeth Echeverria wrote:Is there a way to just get the 'Rocket Cooktop with a Lorena Option' plans or video a la carte instead of the whole 16 hours of the free heat videos that's offered as a big bundle?? thanks!

Hi Elizabeth!

Here is the pre-order thread for just the Rocket Cooktop with a Lorena Option:

https://permies.com/t/193727/Plans-Rocket-Cooktop-Lorena-Option

The plans are in the very last stages and shall be up in the next days. We received a lot of good notes that weve applied to make them a lot richer.

Cheers!

Awesome, thanks so much!

Is there a way to just get the 'Rocket Cooktop with a Lorena Option' plans or video a la carte instead of the whole 16 hours of the free heat videos that's offered as a big bundle?? thanks!

This was a really great video. I have Erica and Ernie's book, but this was a colorful way to complement that and bring the designs in the book to life.