wretha0001

It’s been a while since I’ve written an update on what we are doing on the cabin, so this time I’ll write about concrete, or more accurately soilcrete. What is soilcrete? It’s nearly the same thing as concrete but using local materials instead of using purchased materials. We use local dirt, gravel from the creek, portland cement and of course water. This makes a strong and inexpensive concrete/soilcrete to make walls and such.

I thought a few pictures would liven things up a bit. I was on the west deck, Bob didn’t know I was there so I was able to snap a few candid shots. You can click on the pictures to view the full sized image.

Bob mixing soilcrete

We use lots of plastic 5 gallon buckets. Before I left my old job, Best Buy, we had a huge hail storm. It damaged the roof pretty severely, the store purchased several dozen of these 5 gallon buckets to try to catch the dripping water from the damaged roof. Just before I left, I asked if I could have the buckets, I expected the manager to give me a few, I was pleasantly surprised when he gave me half of them!

All of these buckets have sure come in handy, thanks Best Buy!

Bob mixing soilcrete

Bob has gotten the mix down to this formula, he uses 2 buckets of gravel from the creek with a bit of sand, 1/4 to 1/2 bucket portland cement, same amount of soil/dirt, 3/4 bucket water. Just like any recipe, this mixture is approximate, Bob adds more of whatever is needed to make the mixture look right. This is what works for us, your mileage may vary. Also our soil has very little to no clay in it, also make sure to keep out as much organic material as possible.

We have to use the materials we can get or already have on hand. Bob is pouring a wall and is using scrap wood to help funnel the mixture into the cavity.

Bob pouring soilcrete

Dumping another load of soilcrete. The concrete mixer is from Harbor Freight, the price was right and it works pretty well for us. You might notice the one white glove, no this isn’t a tribute to Michael Jackson. A couple of days ago, Bob got his fingers on that hand caught in the cement mixer, his first and second finger went almost all the way through the gears that turn the tub. It chewed the tips of his fingers up pretty good, but no permenant damage was done thank God. He was out of commission for a few days. Today he announced that he wanted to do another pour, so he wore that one glove to protect his wounded fingers, mainly from the dirt and cement powder.

Pouring the mixture into the wall cavity.

Bob pouring soilcrete

Bob pouring soilcrete into the wall cavity.

Bob mixing soilcrete

This is the inside view of where Bob is pouring the soilcrete.

Under the cabin

A closer view of under the cabin. The corner in the center of the wall is where the soilcrete wraps around a post.

Under the cabin

Another view under the cabin, Bob has been digging out the floor, he dug down 2 feet, the posts in the ground go down 3 feet, I’d say he has nearly 3/4 of the area dug out.

Another view under the cabin.

Detail of the floor joist under the cabin.

These are the posts supporting the cabin.

Bob dug down and had to reinforce the concrete around the post.

Another view under the cabin.

Another view under the cabin.

This is in front of the cabin, this old tree was struck by lightening many years ago, we have left it up as a habitat for the birds, lizards and other critters that like it.

Here is the cabin as it looks now. Bob is slowly building up the concrete walls that will eventually wrap all the way around the cabin. This will add strength, protect us from animals and fire.

Another view of the cabin, you are seeing the south facing side. This also shows the top of my mountain.

This is a closeup of the mosses and lichens that grow on the trees, it really comes to life when it rains.

Here is where the travel trailer ended up. Bob is working on reinforcing the floor and making it more acceptable for guests to stay in.

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10 Responses to “Soilcrete”

  1. Colin Waddell

    I have successfully added vermiculite and Styrofoam chips to soilcrete projects. Thought I would share this info as Styrofoam is usually readily available, free-of-charge and vermiculite can be purchased in bulk at reasonable prices. They both have great insulating properties, bind well with soil and cement, and can reduce weight up to 35%. Bearing walls would require more info than I can provide.
    We experimented with such a mixture, (35% Styrofoam, 45% sandy soil and 20% Portland) to make some ornamental objects, including large planters, paving stones and benches. This was 20-30 years ago. They are still around today, (except the benches which the G’kids destroyed.) The Styrofoam must be chipped to about 1/2”. Larger chunks can become exposed as time and weather take their toll on the surfaces. I would recommend vermiculite for planters as it absorbs and retains water. For all other purposes, Styrofoam is the deal. I’m sure that there are many other substances that could be recycled into soilcrete. A neighbour built a wall in his greenhouse using wine bottles within soilcrete blocks. His soilcrete also had a high content of broken glass. The roof fell in last year from snow-load but this wall stood as strong as the other ’stick-built’ sections.
    We have also discovered that uncrushed river rock and sand are poor ingredients in any concrete. The polishing action of running water leaves few rough edges for the cement to bind with. It appears to work well at first but starts to disintegrate within a very few years.

    Reply
  2. Wretha

    j.r. guerra in s. tx, thanks for the info, doubt we would use block construction though, it’s far easier to pour in place, at least is it for us. We are lazy too. :)
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    Gwen, thanks yes that space under the cabin will be utilized this summer, it does get quite warm inside the cabin, last summer Bob spent lots of time under there, it was a bit too much for me then, but I’ll bet I’ll be spending some time down there this summer now that it’s dug out and more closed in. I also have an idea for a space under there for a root cellar, great minds think alike!
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    Mark, yup, it is a lot of work, I get tired just watching Bob lug those buckets back and forth (grin). Bob usually does one or two loads (cement mixer bowl) at a time so it isn’t so much work each time, then he lets it set up and starts up the following day.
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    Dave, that’s good info to have, I suspected this type of construction should be able to stand the test of time. It’s very dry here so the wood shouldn’t rot, that’s the weakest part of the system.
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    tsmith, thanks, hmmmm people ask me for advice all the time, (I don’t mind though), I usually give the same general answer, if you really want to do it, then start buying the components needed, one or two pieces at a time, buy solar panels, buy the charge controller, start doing this now, at least once a month, preferably something out of each paycheck, and once you are ready to take the plunge, even if it’s years from now, you will have a major head start on your off grid life. Also, I suggest that you start NOW buying extra foods, canned, dried, anything that doesn’t require refrigeration and will last a long time, even if it’s only a few extra cans of something or a few extra bags of rice or beans, do it, you will never be sorry about having extra food.
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    Rio Arriba, thanks, Bob’s fingers are healing up nicely, the fingernails on each one that went through the mixer are coming loose, he’s trimming them off, but other than that, they are looking good.
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    #7, thanks for the link :)
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    Antti Karttunen, thanks for the link! :)

    Reply
  3. Antti Karttunen

    There is currently a discussion about the same topic
    going on at:
    http://openfarmtech.org/weblog/?p=560

    Reply
  4. Making “Soilcrete” for Your Shelter | The Raw Land Guide

    […] This link has an updated pictorial of the construction efforts. This link explains what and “the why” of what she is doing. Easy AdSenser by Unreal […]

    Reply
  5. Rio Arriba

    Looks like it’s coming along real well. Always something to do! Hope his fingers heal up soon. Musta hurt like hell.

    Reply
  6. tsmith

    Great work! thanks for posting. Any suggestions for others to research off-grid living?

    Reply
  7. Dave

    Here in Ireland, there are a number of outhouses build using this same method by my father and grandfather over 60 years ago. Built the same way – gravel from the river, stony/soil from the farm, cement and timber shuttering. All mixed by shovel and handballed into the shuttering. The buildings are still standing and more importantly still in use.

    Nice work and best of luck.

    Dave

    Reply
  8. Mark

    Thanks for the update and pictures Wretha. Looks like things are getting done. That concrete looks like alot of work, but it will be well worth it in the end I suppose. C’ya later.
    Mark

    Reply
  9. Gwen

    Great photos, Wretha. It looks like that space under the cabin will be perfect for keeping cool this summer and maybe doing some root cellar-type storage. Nice!

    Reply
  10. j.r. guerra in s. tx.

    Very cool – you are pouring courses of this stuff. Used to be (and maybe still exists) a block press which pressed blocks of soil cement units. Called the CINVA RAM, it made blocks approximately 12″ long x 6″ wide sx 3″ deep. Designed back in 70’s, you find some used presses here and there. Even came with forms to make roof / floor tile, and even lintel ‘U block’ for reinforcement over wall openings.

    You go girl! Man, talk about inspriration for us lazy folk. Definitely one of those ‘thems thats doing’.

    Reply

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