WHAT ARE EARTHBAGS AND WHY AM I BUILDING WITH THEM?

Building with earthbags is essentially building with adobe bricks without going through the lengthy process of making them. You take polypropylene sandbags, fill them with a moist mix of sand and clay, tamp them down hard and connect the layers with 4 point barbed wire. Then, you cover them over with an earthen plaster.

In reality, I didn't use polypropylene bags. Some Brasilians started a type of construction they call hyperadobe which uses mesh bags, or continuous tubing, made from the same material as the onion or potato bags in the grocery store. They don't require barbed wire, though otherwise the process is just about the same.

As I talk about in the blog posts, my design has been guided by simplicity and efficiency. More than anything, what's been most important to me is to live in a house that I myself, with no building experience whatsoever, can design, build and maintain. A natural extension of that has been the desire to live in a peaceful space. For me that means a home that's in tune with nature, thus limiting the use of imported materials for construction, in addition to those that will be needed later on, such as for heating. Please enjoy reading, ask me any questions, get inspired, and come help and learn!

Wednesday, July 27, 2011

Is this Pisa?

Leaning box for flue

Heavy leaning 3x4 frame

Door frame with bowed buck

Straight! 3x5

Leaning wall on the other side of the window in the foreground

Other leaning 3x4...perhaps the worst

High walls!


So am I freaking out? Frames are leaning, doors are bowed, walls leaning in...no worries. Luckily, I discovered the first instance of leaning with a 3x4 which isn't a window but a piece of glass that I could just plaster in if I wanted to. Could have been something pretty disastrous if it was on the 3x5 operable windows. I became attentive after that. The door...tried what we could but dirt has push and I don't think there was much of a way around it except for using larger wood or having a horizontal brace in the middle. I also left extra space so it should be fine and if not I could always saw out the frame and screw the door jamb directly into the walls instead. The leaning wall. Well...would have paid more attention to plumb. Should have. Could have. But I didn't and...I don't think it's the biggest deal. Also, looks worse than it is because of the curve it's on. It's done but I've got some advice if you haven't done these things yet!

I believe the bowing for the door was more or less inevitable. If I were to do it again...I would leave extra space in the rough opening so that if it leans an inch one way it'll be okay. As far as leaning frames it's totally avoidable. Don't remove any of the braces--front, back or cross--until the bag work is at or close to the top and stuff has had a chance to dry and move the way it wants to. And brace, brace, brace! It needs it more than you think, and even when you think it's okay...it's not! Also, do courses, not areas. The worst leaning frame is where we had done everything up to it but not on the other side because we hadn't backfilled that area yet. Even if it's the same day, the dirt will knock things out of whack. Oh, and get your wood from somewhere besides Ace. My wood started out warped and twisted so that just compounded with everything else.

As far as plumb. Be more diligent than me about checking it with a level?

I've also found that screwing the frames into the embedded wood is the better way to go. If stuff starts to lean then it can stop being flush. Longer screws work, but probably not as good as having the two neat and cozy together.

All in all I'm stoked. Having Kevin out here has been great. We've gotten lots done and as always it's easier with two than with one. I continue to get scrap wood (picked up a load yesterday), and am actually going to get some plexiglass which will be great for a greenhouse (next year,) and got a box of neoprene (for the metal roof) screws! All the walls are up to their respective lintel levels...which means the lower lintel for each section so there's still some wall to build up. We've backfilled the whole south side just a few inches above where it will finally be. The next couple days we'll be plastering. This time I think I'll actually plaster instead of doing a thin cover coat for uv rays like before. With the rain some of it has run off because it's so clayey and thin and I've got to put a thick coat on some time so why not now? Next week holds more backfilling then lintels! lintels!

7 comments:

  1. Just curious - how high are you going with the walls ultimately?

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  2. On the north end I'm taking them to about 6.5 feet from the finished floor, which is 7.5 feet of bag stacking altogether, which is 4.5 above ground. south side is somewhere around 10 feet of stacking altogether...basically just going high enough to put the lintels above the windows and do two more courses. The door area might end up doing a funky little flare so I can have the south side be only as high as my 3x5 windows and not as high as the door except directly over it...if any of that made any sense.

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  3. Hi
    I was kind of concerned that this would happen. Between the heat warping the wood and the settling of the walls, the entire building is in flux. That is one of the reasons in conventional building we make the openings larger then the windows and doors. It is also the reason we install the windows and doors last and do not nail the snot out of them. Even after a house is framed, there is movement. If a door doesn't close or the margins around the window change,the situation can be fixed easier if it isn't permanently locked into place.

    The roof situation is another point I was concerned about. You have to have a minimum slope for the metal roofing. That means to orient the shed roof front to back, or north /south the walls have to be the correct height. If I remember correctly the width of the house is 16ft. At a 3/12 pitch that means there needs to be 4ft difference between the front wall height and the back wall height. The reason I suggested going with a gable instead of the shed was to give you the wall height you needed for the doors and windows.

    I wouldn't recommend you start plastering yet. Your going to continue to have movement in the walls. Wait till after you have the full weight of the roof on. Also the roof overhangs will protect the earth adobe plaster. If you need to cover the bags quickly, either rent an airless sprayer and paint it (diluted paint) or use a mortar sprayer. Incorrectly mixed paint can be had cheaply.
    Email me, if you need some help or problem solving.

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  4. Wow, you are doing it!! Looks like a tremendous amount of hard work. Hope you are doing well missy! I think are due for a CA visit soon, no?

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  5. Claire! I miss you!! I don't know about that Cali visit though...

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  6. Didn't know you too were writing a builder's manual Brad :-). Let me know when I can get an advance copy.

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  7. Aly, your at the top of my book list. :-)

    Just trying to help you avoid some of the pitfalls that many people unfamiliar to building make. While some are correctable some can have a negative lasting effect on the building and it's inhabitants. It is entirely up to you to decide which path to choose. I am only offering up the knowledge and experience as a way of giving back.

    Many problems can be avoided by building in a proper sequence. Take for instance plastering before the roof is on. Seems innocuous enough. But the weight of the roof will cause more movement and settling. Wall movement and settling causes cracking. Adding extra coats of plaster, be it earth or lime to fix the cracks, takes time and material. That is why usually plastering is done after the roof is on.

    I understand most people new to building have little understanding of the work, time and effort it takes to complete a house. Many times they get in a hurry and want to bypass a something to save time or money. Usually this causes problems down the road. Avoiding costly mistakes is serious business especially when your on a fixed budget.

    Like I said before, there are usually good reasons behind most common building practices. They have been tried and used successfully for years.

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