Andrew Lubrino

I'm looking for some calculus on earth bermed and underground houses. It makes intuitive sense that they stay cooler in summer and warmer in winter. I've heard that these kinds of homes are typically very humid, though. So even if your heating and cooling costs are lower, you'll need to plug in a dehumidifier (which is basically a small AC unit) and run it 24/7/365. On top of that, the house will probably sustain water damage from the ground, which also increases repair and maintenance costs and lowers the lifespan of the home.

Then, on top of it all, you need to use a bunch of plastic to make this idea work at all. If petroleum-based plastics became prohibitively expensive, would this kind of housing still be viable?

For anyone who lives in an earth bermed house, are your electricity and fuel needs really lower? How do you find issues with humidity? I live in the northeast U.S., so would be most interested in experiences from that region.

I think you actually did mention it, and I just overlooked your comment. This is how learning occurs. One good thing is that I do have it covered with a tarp. The slab has a variable thickness because it's poured on top of the stones I laid in the hole. On average it is probably about 3 inches I'd guess.

So, I'll wait another two weeks and see if it hardens up sufficiently. How will I know if it is hard enough to build on? Any details on texture, hardness ,etc.? I'm guessing if it's spongy, it's just bad and needs to be dug up.

Also, if the concrete ends up not being hard enough in the end and I need to repour - any tips on getting the mix right? Should I be able form it into a ball? Should it be crumbly? And how do I dispose of the old pour?

A lot of questions here, so thanks!

A quick update here. I poured my soil-concrete pad last Saturday with some mortar mix I had lying around. The pad is okay. I mixed the soil-concrete in two batches. The first one seemed really wet, so in the second mix I lowered the water by a lot.

After 5 days, both sides are certainly firm enough to walk on. On the side that had the more wet mix, the surface is a bit spongy and when I walk on it, my shoe makes a very small impression (maybe about 1/16" deep or so). One the side with the drier mix, my shoe doesn't make an impression at all. The dry side is quite hard, but I can still scratch away the surface with my fingernail.

Does this sound right? Will this be hard enough to build on?

Cristobal Cristo wrote:Andrew,

Mortar Type S has cement to lime to sand ratio: 1 : 0.5 : 4.5, so in the mix 1/6th is the cement. So in case you want to make dirt amended with 10% cement you would need to use 10 part dirt 6 part S Type mix. For 5% stabilization you would use 10 parts dirt and 3 parts S Type.

That’s a good point. I was planning to do 10-1, but you’re right, it should be 10-6. This will be my test bed initially, but if it’s strong enough I might just build with mortar here. I’ll see how it goes.

When you say 10 parts dirt to 6 parts mortar mix, is that by volume or weight? If volume, is there a good way to measure the volume? Just buckets I guess.

I'm starting this thread here as a journal for my masonry rocket oven build.  Here are the list of materials I'm using:'

About 120 dense firebricks that someone on Craigslist gave me for free

A bucket of pure clay soil I dug out of the ground near a natural lake

About 75 red bricks (again, from Craigslist)

About 3/4 of a bag of Type S masonry mix that was sitting in my house's shed from the previous owner

A bunch of boulders laying around my property

Construction began last weekend. I started in the morning and dug a trench about 2' x 4' and 2' feet deep. For the area in NJ where I live, I should have gone down 3', but oh well. Let's see if it fails. As we dug out the dirt, we screened it and used the gravel to fill and inch or two at the bottom of the trench for drainage. Then we filled with the boulders.

Next step will be the concrete pad. I plan to mix the bit of mortar mix I have with some dirt to make a dirt cement. Will that be strong enough? I need something that I can pour over the rough surface of the rocks.

Cristobal Cristo wrote:Andrew,
I would recommend that you first try different designs for few months, before you commit to something more serious.

I didn't think of this, but now that you mention it, that is a great suggestion. Thank you!

For a dry stacked version that I'm playing around with, is it even worth building the foundation? Or should I hold off on that for now while I'm still testing?

I'm planning to build this dense fire brick (not the insulated kind). Will that stand up to the weather (rain, wind, etc.)?

I'm sorry it has taken me so long to reply on all this. I'm definitely going to start a rocket oven build thread to document everything I'm doing. I've made a few decisions over the past few days and I think I'm really close to starting on this. I've decided to build the oven itself with all masonry - so core + oven and an additional stove top on the core. To do that I'm going to use Matt Walker's riser-less design, which also seems pretty easy to build and sits closer to the ground. One more question I have on the foundation:

I'm on a pretty tight budget with this build. I looked into pouring concrete and it's just too expensive for me, so here's what I'm thinking. I basically live on top of a mountain. The soil is basically pure gravel with large boulders mixed in. The sloped land also assists with drainage.

I'm thinking of using some of these giant granite stones I have laying around for the foundation. I'll dig to a depth of three or four feet (the frost line in NJ) and throw in some of those boulders as flat as I can and then sand on top of each course of rocks for leveling. Does that sound like it will work? Some sources say you should really put down gravel as a base layer. I could do that, but gravel also is not cheap at all, and my soil is already excessively well-drained. Seems silly to put more of that in there.

Where I live, pretty much every single house, including mine, has a stone foundation and was built 100 years ago or more. I doubt they used gravel back then and every house around here seems pretty rock solid.

are you looking for an oven or a stove?

I'm looking for a cooking apparatus with a stove top to cook with pans and then an oven. Something similar to a regular oven that runs on natural gas in the kitchen, just outside and powered by wood.

Benjamin Dinkel wrote:
Do you have a thread about the design of your oven?

I don't. Should I create one of those? I was originally thinking of building one of the designs from Tim Barker's book. That book's design is very simple, but it lacks some detail and as I read more about other designs, I'm thinking it might not be exactly what I'm looking for.

Any resources on how to pick a design? After some reading, it seems like there are three major contenders: Walker riserless core, a batch rocket, and a traditional J-tube. This oven / stove will mainly be for us to cook with outside during the heat of the summer. The walker oven appeals to me because a. it's all masonry with no ugly looking barrel and it sits closer to the ground instead of having a masonry tower. The drawback is that it seems to produce a lot of radiant heat. For me, that would be lost heat - I'd want everything to go to the cooking chamber.

I could stick with the original J-tube, but it's just so ugly. Not sure the wife will accept that thing sitting in the yard. Thoughts? Sorry for the brain dump.

Okay, I see what you did here and this exactly answers my question. The answer is 100% yes, I need some insulation  under the oven. Is the insulated fire brick necessary? Or will the perlite do the trick on its own?

Also, your oven looks great. Thanks for sharing!

Cristobal Cristo wrote:
I'm not building a dome oven. It's a batch box rocket with little bit different proportions and rectangular heat riser

I'm confused. Does the perlite concrete go between the concrete pad and the J-tube? Or is the concrete pad itself made of the concrete perlite? Or does it go somewhere else?

I'm new to rocket ovens, and I'm totally unfamiliar with a batch rocket oven. I spent the last ten minutes reading about it and I'm still unsure where you're putting your pizza from your description. Any good links to learn more about batch rocket ovens?