The Nicaraguan earthen oven

Here are only a few pictures of our earthen oven being made by Felix and Winston. If anyone is interested in learning more about the Nica method of earthen oven building, my own personal web page will have more photos w/ detailed explanation soon. www.casalachabola.com.  Until then, here's a small glimpse of how it's done, local-style.

oven base: small tree trunks, covered with 6 mm plastic then topped with tampped earth and sand encased by four wood planks. General oven structure: adobe bricks w/ clay-horse manure mix as mortar. Rebar as mini cross beam for doors. Oven floor: adobe floor tiles

very top of oven closed-in by broken peices of adobe roof tile and clay-horse manure mix.

finished product: bread entrance door on right, ash exit door on left. doors, and decorative elements to come...

Nica Linda's Blog
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Linda. That looks like it ought to be a very useful oven when it is completed.

A couple of questions, when you can spare the time to answer:

1. The clay I understand, but not the horse manure. Does the manure contribute fiber, therefore additional strength, like straw does in other adobe mixes?

2. Will the horse manure odor dissipate after several firings?

3. Why a wooden base, instead of stone or adobe? I would have thought that wood would be more susceptible to decay or termite attack, particularly in your climate. Or is there an expectation that the next hurricane or earthquake will knock everything down before the wood goes bad?

Congrats on a great start.

Paul

There was an episode of Dirty Jobs where they added horse manure to the sand used when they cast bells. It was sifted to remove fibers and what remained had properties that helped keep the shape of the cooling bell. Unfortunately, I don't remember exactly how it helped. Perhaps someone else remembers?

I'm also curious about the need for horse manure. Looks like a great start and I'm sure WFO are rewarding. Dave

That is AMAZING!!!!! I too have my questions about horse manure vs whatever else is handy. We are planning to raise goats and make chese, soap and breads in the next 2 years as well as firing some home made pottery. At the risk of sounding really stupid....is it at all possible to use the same oven for the same things....of course not at the same time as I am sure the breads would be charcoal at the pottery firing temps!! But could we use it for them both?? Any suggestions on where to find the info to build them....especially if we have to build 2 different ones...which would be find with me!! GOD I LOVE THIS SITE!!!!

THANK YOU!!

My what beautiful scenery your oven sits in...I too am curious as to your materials and the use of two doors instead of an area outside the front door shelf with an opening to sweep the ash down..my first thought as to seeing your foundation was...are you planning on moving your oven? I can appreciate all the hard work you are putting into your oven.

Sylvia

Hello everyone! First let me apologize for the VERY late reply. Between faulty internet and a busy life in the campo, sometimes it's tough to be on top of it all. IF anyone is interested in a more detailed description of the Nica earthen oven, please click on the following link to read the step-by-step process. http://www.casalachabola.com/La_Chabola/Close_Up/Entries/2009/8/31_Steps_to_building_an_earthen_oven.html Now, to answer your questions: Why Horse manure? When making a natural plaster/mortar out of high clay content subsoil, it's pretty much imperative that you add sand at the very least to increase structural strength. The sand does a great job of reducing cracks and wide gaps in the final dry product. Throwing in some dried up, ground down manure will add even more integrity to your final plaster/mortar. The enzymes in the manure (specifically cow manure) are what make it a great binding agent, thus creating a stickier mix. The little fibers that also make up the manure provide tensile strength to further reduce cracking. The soil around these parts has a very high clay content - it is just beautiful. Since it is plenty sticky, we prefer to use horse manure for added tensile strength without the added stickiness. As far as the smell, I haven't noticed. But maybe I'm used to it by now. I've fired the oven three times already and there is no horse dung odor to speak of. Why the wood base? That's a tough one. I think it's a combo of doing what has always been done and in my case, using what was readily available. The tree branches/small trunks harvested for the base were all found within a 1/4 mile radius and of the highly renewable varieties. Since they were assembled raw (without any chemical treatment) I imagine the bugs are having their own little feast, maybe even as I type. I'm not worried though. All of the materials used in this oven can go right back into the earth the day it crumbles and falls. If it happens sooner than later, I'll have Felix come make another one...maybe using a new method for a base like stone, rather than wood. I think he'd be wiling to try it. Why two doors instead of one? One door, where there is minor landing space in front, is the bread entrance/exit slot. The other door that opens right out to the edge is for extracting the ashes. Felix recommended we put it to the left side because I am right handed - a little detail I might have overlooked. I like the two door method. In order to reduce heat loss, just make sure the door covers seal well. Using the oven as a kiln? Hmmmm, I don't know. I've heard from my neighbors that they have fired pottery in hot holes in the ground rather than in the WFO. But I'm sure the true artisans use some kind of earthen oven as a kiln. Good question. All-in-all this oven project was a way for me to learn how a Nicaraguan earthen oven is made. There are a few things I would change if I were to make another myself, like making a stronger mortar, building a different base and raising it to fit my height. But for now, this one made by Felix is perfect. Again, click the link above for more explanation and photos. Till next time, Linda

I realize this is an old post, but I wanted to read the details on the website posted, but it is no longer valid. I would like to ask about manure specifically. Can I use a higher ratio? Getting clay on my island will prove impossible.