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Natural walls in many strengths

How strong do we need? Get an estimate of quake risk levels from local governments or BSI's map. In areas with other hazards like landslides, tsunamis, artillery or vehicle accidents, details used to resist earthquakes may be helpful.  

Earthen walls do well in white areas of BSI's map

Minimal Strength

Where quake forces are likely <0.25 g or less, traditional earthen huts last hundreds of years unless they decay. Use water-resistant base courses and a roof overhang to prevent damage.

Earthen buildings moderate humidity and temperature swings. Techniques include traditional adobe, puddled adobe, cob, rammed earth and compressed blocks as well as most kinds of plastered earthbag. 

Basics:

More wall than window
Firm footing and moisture break
Walls thick enough for the height
Stiffen long walls with buttresses 
Connect walls well under good lintels and bond beam

Basic best techniques for low risk areas (light gray on BSI's map)

Limited Strength

Where quake forces are likely 0.25- 0.6 g, build with soil at least 1,8 MPa (190 psi) strength. Use field tests to check.

Interconnect footings and walls strongly. Keep stub walls less than 1.2 m (4') long. Space intersecting walls or buttresses regularly every 10- 20' (3- 6 m). Check bracing using information from New Zealand's non-engineered building code (NZS 4299).

Construction details for adobe and rammed earth are included in free versions of NZS 4299 online. Details for compressed block walls are included in the 2020 revised NZS 4299.

Use conventional earthbag techniques with strong (2,1 MPa/ 300 psi) soils. For minimum strength soils, earthbag needs splices linking inserted rebar, or improved reinforcement.

Free Low-Cement CE Construction pdf 

Special reinforcement for medium- high seismic risk (dark gray/ black on BSI's map

Moderate or High Strength

Brittle wall types like most adobe, compressed block and rammed earth must be intensively reinforced on continuous reinforced concrete footings.

More flexible wall types may use footings of gravel bag with wire binding. These include cob and reinforced ICEB (interconnected compressed earth block) as well as improved earthbag. (Use cob in cool areas to protect its natural fibers).

Earthbag's higher ductility requires  less manufactured reinforcement than other walls, but it needs tubes of strong soil with interconnected steel. Use spot corner reinforced concrete (RC) footings or confining RC grade beams.

Free Standard Grade CE Construction pdf

High Strength CE pdf coming soon.

climb the learning curve

Conventional Earthbag Recommended Resources

Format
Description
Price
1.2- 1.6 MB pdfs
Earthbag Info Series, P. Stouter, 2020

Four slide shows introducing earthbag construction with images from around the world.

Free

Find pdfs
DVD
Basic Earthbag Building, O. Geiger, 2011

More than 3 hours of video instruction. Preview his teaching style with free video clips on his youtube channel Naturalhouses.

+$28.00

Amazon
Paperback or kindle
Essential Earthbag Construction: , K. Hart, 2018

144 pages. Drafted and photo illustrations, includes carbon footprint info and more.

+$25.00

Amazon
Paperback or kindle
Earthbag Building: The Tools Tricks and Techniques, K. Hunter and D. Kiffmeyer, 2004

280 pages. Drawn and photo illustrations, includes 40 pages about domes.

+$20.00

Amazon

Earthbag for Seismic Risk Recommended Resources

Format
Description
Price
2- 4 MB pdfs
Resilient CE Construction Series, P. Stouter, 2020

Three booklets with separate information and details for different seismic risk levels.

Low-Cement Resilient CE Earthbag for Low Seismic Risk

Standard Grade Resilient CE Earthbag for Moderate Seismic Risk

Free

Find pdfs
Paperback
Earthbag for Seismic Risk Areas: Resilient CE v 2.1, P. Stouter, 2021

Includes the three best practice booklets plus additional information. 


after June 2021 
pdf
Examples of Resilient Plans for Earthen Buildings: , P. Stouter, 2021


after September 2021
3.3 MB pdf
New Zealand Standards 4299:1998; Earth buildings without specific engineering

Detailed construction information useful to engineers and planners new to designing with earth building walls.

Note: the costly 2020 revision is better for compressed earth block construction but may not have many changes to the adobe information.

Free

Find pdf