.Building a Small "Starter" Straw Bale
Home or Guest House

(low cost to build - ultra energy efficient - no utility costs)


Plans and Budget:

SIZE: 480 square feet, external - 312 square feet, internal
(see plans below)

ESTIMATED COST: under $10,000 including utilities, if you...

1 - are willing if not eager to live simply
2 - do most of the work yourself
3 - use recycled materials whenever possible (and do lots of scrounging)
4 - twist a few friend's arms to help you once in awhile (free pizza works everytime)
5 - price shop around for the best deals on all materials, especially the expensive items like solar panels (get a quote from places like solar energy at Verengo, for example), composting toilet, and metal roofing - prices vary a great deal
6 - stick to the simple design features below - fancier roofs or a concrete foundation, for example, really add to the cost...
7 - can build your starter straw bale without having to permit it (more on this later)


Mini-Version of the Above Plan
(200 square feet, internal)


OVERALL DESIGN: load-bearing straw bale, six courses of bales at the front, seven courses of bales at the back (to accommodate a simple sloping, "shed" type roof)

ROOF: shed roof covered with straw bales which are supported by heavy metal perlins attached to the top plate, straw bales covered over with corrugated metal (such as R-profile, "standing seam" is much more expensive, recommend a "galvalume" finish which does not rust and will last much longer before it needs repainting)

HEATING: passive solar (sun streaming in the south facing door and windows and absorbed by an adobe block floor (or other high "thermal mass" material), small wood burning stove to supplement heat on cold nights

COOLING: small evaporative cooler mounted through an existing window or installed through the wall when the house is built - water for the cooler can be be gravity fed from barrels outside (see below)

SOURCE OF WATER: rain water harvesting from the sloping tin roof of the house and collected into barrels or poly water tanks - water is fed by gravity into the house for the sink (the barrels having been placed high enough on a stand or platform outside)

HOT WATER: in order of increasing cost, here are several options for having hot water for showers and washing dishes without spending money to heat it with fossil fuels (the cost of propane will flatten any budget) or electricity either from the grid or from the solar panels which aren't sufficiently high in power to heat water

1 - heat water in a pot on the top of the wood burning stove

2 - use a simple $12-15 outdoor type portable solar shower (they work amazingly well - we like to use ours even though we now have a regular hot water shower in the house from a large solar hot water system)

3 - build a box painted black with a glass top and run inexpensive black irrigation pipe through it - gravity fed or install a small RV circulating pump

4 - build a "batch" solar hot water unit (a small tank on the roof painted black)

5 - buy a commercial"flat-plate" solar hot water collector for the roof

6 - buy an "evacuated heat tube" type solar hot water unit such as the Thermomax - high output, expensive, and not really necessary for a small "starter" straw bale - see our Hydronic Heating Page about this unit


Thermalstar, a unit made in Canada which has come out recently, combines both the high output of "evacuated heat tubes" and a large gravity fed batch tank on the roof - It received an excellent review in Home Power Magazine, Issue 97. Cost is about $700.


"Kloss" system for best energy efficiency (all windows and doors are doubled with a horizontal mini-blind installed in the 5-6" air space left between them)

FOUNDATION: trench filled with rubble (bits of concrete, stones, gravel), then built up with earth bags to make a small stem wall for the bales to rest on (see picture at right) - note that the bale walls are "pinned" with bamboo on the outside of the bales (this eliminates the need to use "all thread" up through the middle of the bales which is a pain to do and expensive) - for a complete description of rubble trench foundations, see "Mortgage Free! Radical Stratagies for Home Ownership" by Rob Roy: A Real Goods Solar Living Book, 1998

TOILET: use a composting toilet if allowed in your area (septic systems are expensive, use/waste a lot of water, and waste the "good stuff" which would be better utilized in your garden)

FLOOR: handmade adobe earthen floor or lay thick pre-made adobe blocks or conventional bricks -- for high "thermal mass" to absorb heat from the sun during the day and radiate it back out into the house at night

ELECTRIC: small solar electric (PV) system with a few panels, storage batteries, and a small inverter for computer and stereo equipment - using as many 12 volt DC lights and appliances as possible will save electricity and mean you can get by with a small and less expensive PV system...

FINAL PLASTERING: use either lime stucco or adobe earthen plaster to completely seal the bales and protect them from moisture as well as insects and other critters - cement stucco is not recommended (see http://www.solarhaven.org/Construction4Lime.htm for more about this)

CREATIVE TOUCHES: by adding more earthen plaster mixed with more straw and colored pigments (historically called "cob"), you can build up and hand sculpture door and window openings to make your little castle very special indeed -- the only limit is your time and imagination...


Other Natural or Recycled Materials
Which Can Be Substitued for the Straw Bale Walls:




VERY IMPORTANT: many counties in the United States do not allow some of the design features outlined above, such as a composting toilet, external strapping, or a rubble trench/earth bag foundation, and will require a building permit if your house is over a certain square footage - check before starting!! If you must take out a permit and observe your county's building codes, the cost of your house will be increased by approximately 40-50% -- about $10,800 for both the house and utilities instead of around $7,000. Compare this, however, to what you would get if you were to buy anything in a housing subdivision these days - a bigger house than you need, an inferior less energy efficient place to live at a much higher price, a big mortgage payment to come up with every month, and unending utility bills...

Starter Straw Bale House - approximate expenses:

- Gravel for foundation - $100
- Polyethylene bags and barbed-wire for earth bags - $60

- 120 construction grade straw bales @ $4.50 each - $540
- Bamboo for external pinning - $50
- Galvanized R-profile metal sheeting for roof (new) - $800
- Screws with polypropolyne washers - $40
- Guttering materials for the rain water catchment system - $100
- 3" thin-wall pipe and connectors - $40
- Some wood for window and door "bucks" which can not be scrounged - $100
- Material for external strapping - $100
- Two 6' sliding-glass patio doors (used) - $150
- Eight single-pane windows (used) - $200
- Window caulking tubes - $75
- Used sink - $30
- Lime and high-clay content soil for adobe/line plaster - $300
- Washed sand - $100
- "How could I have forgotten that?" - $500
- Subtotal = $3450


- Composting toilet - $1200
- Two 100 watt PV panels - $900
- Three deep-cycle lead-acid batteries (refurbished) - $150
- 300 watt DC-AC sinewave inverter - $150
- Battery cables, connectors, wire, and 12 volt lights - $250
- Solar hot water unit - $700
- Wood-burning stove (used) - $150
- Pipe and roof sleeve - $50
- Subtotal = $3550

Total Expenses for House and Utilities: $7000
(under the conditions outlined at the beginning of this page)

Additional expenses if the house must be permitted
and meet typical building-code requirements

- County permit fees (they keep creeping up) - $600
- Concrete foundation (two feet wide for straw bale houses) - $2000
- Septic system (composting toilet eliminated, but $1200 cost still kept in) - $700
- Extra plumbing costs - $500
- Extra electrical costs - $200
- Subtotal = $3800

Total Expenses for House and Utilities if Permitted: $11,000

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