Roundwood Braces

Roundwood Braces

One way to save money and reduce your impact on the environment is to use unmilled roundwood when building your home. Wood in the round is much stronger than standard dimension lumber and requires less processing. In our case it enables us to use local, sustainably grown wood instead of wood shipped hundreds of miles. Plus, because we’re using eucalyptus wood our roundwood is fairly durable and insect resistant. Using roundwood does take a bit of extra work, but I feel the benefits make it well worthwhile.

We use roundwood for many purposes, including corner braces to keep window and door bucks square, braces to prevent bowing of frames, long poles to keep window and door bucks plumb, stakes and even nailers for attaching electrical junction boxes, shelving, etc.

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Sheet Metal Anchors

Sheet Metal Anchors for Rough Frames

It seems most people are using wood to attach rough frames (“bucks”) for windows and doors to earthbags. We have termites in our area and so we’re using galvanized sheet metal for this purpose. I’ve used both kinds and discovered sheet metal anchors are much faster to make.

The first step is to cut sheet metal into 7”x12” rectangles with tin snips. (We paid a little extra to have them pre-cut.) Then score a line 2” from one end with a large nail and straight edge. (We used a 16d nail and a piece of sheet metal.) Score the metal about three times and then bend it along the line into a right angle with your hand. Pound in some nails from the bottom side, place the anchor in position and then add nails into the earthbags (galvanized roofing nails work best), and deck screws into the wood. Place anchors on both sides of frames about every four courses of bags.

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The Dometown Project

The Dometown Project

I’ve been corresponding with Richard Laurens who is developing a geodesic dome design that rests on earthbags and is covered in earthbags. His original plan was to use rammed tires to support the domes, but now he’s convinced earthbags are more practical. I’m encouraging him to use scoria-filled bags since he plans to build his designs out west near a source of scoria.

I’ll let Richard describe his project in his own words.

The Dometown project is a name I gave to my plan for a small cluster of dome shaped homes. I would start with one, and keep on building them. The center clear parts are greenhouses.

Buckminster Fuller’s original idea was a home that could be built anywhere for cheap; why not expand that idea into a “life pod” that can recycle water and grow its own food? The basic premise is this: We have a water source, an “eternal” power source (wind, water, or solar), and very contemporary and comfortable self-sustaining dome home. It’s just a very simple solution, and expandable.

The geodesic, or monolithic dome structure is not only appealing to the eye, it is efficient and cheap to build. The dome numbers and designs are nearly limitless, and four simple domes with a fifth dome in the center would make an excellent home with about 2500 square feet of space. That is a good sized home! I estimate working by hand with minimal tools. I can make this house in about a year for around $20,000.

The dome is a 4th degree electrical conduit pipe dome, bolted at the vertexes and welded. I then cover the dome with wire mesh and stack the bags on the outside. The windows are standard ones, placed into a ‘work horse’ type of sconce.

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Structural Mesh

Structural Mesh

Wrapping walls in mesh – starting under the first course of bags and going over the top of the bond beam – is a simple way to add a great deal of extra strength to your earthbag structure.

Fishing net and plastic lath are ideal for wet climates. Galvanized wire lath or chicken wire is suitable for most situations.

Overlap mesh at least 12” (30cm) and keep seams at least 24” (60cm) from corners.

Lay 24” (60cm) pieces of strong twine or cord across the bags every three or four courses and every 24” (60cm) horizontally along the wall. Use this to firmly tie mesh on both sides of wall together.

Drawing credit to Patti Stouter.

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Estimating Costs

It’s not difficult estimating costs for small houses. Simply add up the number of each main component and multiply times a realistic cost. Then add about 5%-10% extra to cover unforeseen expenses. Use current, local prices for most accurate results.

Here’s one article that explains how to estimate the number of bags you’ll need.

You can also do a per square foot cost estimate. This method is not as accurate as a detailed cost breakdown, but does provide a rough estimate.

Here’s one example using dirt cheap building techniques. $10/sq. foot is about as low as you can get using simple, low cost materials and methods (earthbags, rubble trench, earth plaster, locally harvested wood, recycled materials, etc.). So a house of about 300 square feet would cost around $3,000 not including land or labor. (300 x $10 = $3,000) Then add any extras you may want: radiant heat, better windows, tile counters, etc. to get a more accurate cost. The cost will be significantly higher if building in areas where you have to meet building codes. Seek out remote, rural areas with few or no building codes to minimize costs.

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Purchasing Earthbags Directly from China

I got a fortuitous email from the sales manager of a large factory in China that manufactures polypropylene bags wanting my business. During the course of our email exchanges I was able to find out what they can offer by way of bags, costs and transportation.

The China Forest Packaging Group in Qingdao, China can provide a wide range of polypropylene bags, both as individually sewn bags, and as long tubes on rolls. They ship via containers and can send these all over the world…including Haiti.

Standard 18″ X 30″ bags run about $0.11US each and the longer 18″ X 34″ bags are about $0.12 each. The same bags with UV stabilization are about a penny more. These prices are FOB Qingdao. The cost of shipping a 40′ container to the East coast of the US runs about $3,200US and this can hold about 330,000 bags….so this would add about a penny per bag.

The long tubing in rolls are 3500 meters (11,150′ or 2.2 miles) long. This is the equivalence of about 3,700 standard bags. The cost of each roll is about $482US, so that would mean that the equivalent price compared to individual bags is about $0.13US…so there is no saving in buying the long rolls.

They can supply gussetted bags by special order, and it would be necessary to give them exact specifications for this.

They need up to 30 days lead time to fill orders.

For more information you can contact Bill Chen, the Sales Manager. (He does communicate in English). chinaforestpackATgmail.com   Tel: +86 151 656 64026  Fax:+86 536 827 3455

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Alternative Bond Beams for Straight Walls

My previous post described an alternative bond beam for curved walls; this post is on straight walls. Conventional reinforced concrete bond beams may not be affordable or the materials unavailable. Or maybe you want to reduce or avoid using cement. Here’s one low-tech, low-cost bond beam design. It’s even possible to use salvaged materials for all or most of this bond beam.

Alternative Bond Beams for Straight Walls

Materials: Corrugated metal roofing, 2×4 (5x10cm) wood, metal brackets/mending plates and screws, 16d nails, ½” rebar, and twine, rope or strapping.

In this design, corrugated metal and wood top plates are bound together with twine or strapping to stiffen tops of walls. Top plates, joined with metal plates, provide for easy attachment of trusses or rafters. Drill holes in top plates every 24” (60cm) for rebar pins.

Vertical rebar pins about 24” (60cm) long tie the bond beam into the wall below. Driving the rebar at alternating angles adds strength.

Use 8-12” (20-30cm) wide pieces of corrugated metal roofing overlapped at ends about 12” (30 cm) and nailed to the bag below at overlap points. Lay two courses of earth-filled bags above the corrugated metal strips.

Drawing credit to Patti Stouter.

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Alternative Bond Beam for Curved Structures

Alternative Bond Beam for Curved Structures

Forming bond beams for roundhouses and other curved structures is somewhat difficult. Here’s a brief description of an alternative bond beam that requires little or no formwork. It’s made with two layers of long poly tubes filled with stabilized soil (non-seismic zones) or concrete (seismic zones). Tubes could be filled 3″-4″ thick to save on cement. Put barbed wire and horizontal rebar (pinned in place) between the tubes as shown. Add vertical rebar to pin the bond beam to lower courses. Add lintels (or temporary supports if using concrete) over door and window openings. You could add strapping or wrap plaster mesh over the bond beam for added strength.

Note on fasteners for horizontal rebar: use H-shaped custom made fasteners with prongs that embed into bottom and top tubes.

Note on using concrete-filled tubes: you will need scaffolding/planks set up along the wall to pour the upper tube. Two sets of scaffolding could be leapfrogged.

Special thanks to Patti Stouter for the drawing.

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Earthbag Structures for Disaster-Prone Areas

Ever since the earthquake in Haiti we have been inundated with requests for information about using earthbags for reconstruction efforts. Owen Geiger and I have joined with Patti Stouter to assemble a coherent response to this need that is based on our understanding of the strengths and weaknesses of earthbag building, coupled with some knowledge of the cultural factors involved.

What has evolved is a body of information that is readily available to anyone with internet access, and can be found at www.earthbagstructures.com…a new website created just for this purpose. What you will find there are basic tutorials for building, details about how to go about choosing appropriate plans, a discussion of the cultural factors that should influence your decisions (especially for Haiti), some basic plans for emergency shelters and for more permanent housing (and some that can transition from one to the other), structural details, profiles of actual projects with pictures, a discussion of the costs involved, a listing of resources available and where training might be found, plus some technical data about testing that has been done with earthbags.

In addition to this we have created a private discussion forum for those who are directly involved and want to network with others, and there is information about how to join this.

Each page has a Translate Button at the top where you can choose from dozens of languages with which to read the page, including Haitian Creole.

We feel that this will be a valuable resource for anyone wanting to assist people in need of shelter around the world, especially in disaster-prone regions. We expect that this website will be expanding considerably over time, as we develop more plans, construction details, and can profile more projects.

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All-in-One Outdoor Oven, Stove, Grill & Smoker

All-in-One Outdoor Oven, Stove, Grill & Smoker

Once you’ve built your dream earthbag house, you’ll need an efficient means of cooking. At our house, this includes an oven as one part of our outdoor kitchen that keeps heat out of the house. This latest project was a collaboration by Owen Geiger and Mother Earth News Magazine to develop a super efficient multiple-use stove. Instead of building a brick barbecue, smoker and pizza oven separately, you can build just one stove that can cook everything.

The key to its efficiency is a thick layer of lightweight perlite cement around the sides and bottom of the firebrick firebox. Perlite is highly insulating and helps hold the heat where it’s needed.
The oven is made of standard materials available at local hardware or building stores — concrete blocks and firebricks — that will last a long time. And the price is right — only about $300 plus the chimney.

Click to read the full article for free at Mother Earth News.

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