CCAT papercrete clayslip demo wall: Difference between revisions

Project data

Authors	Myles Danforth
Location	Arcata, California
Status	Prototyped
Completed	2009
Made	Yes
Replicated	No
Cost	USD 44
Instance of	Clay wall
OKH Manifest	Download

This page describes the materials, processes, and work that goes into making a small covered wall made from natural construction materials and covered with natural plasters. This project was completed in May of 2009. Constructed, with the help of CCAT and student volunteers, from stick frame and infilled with papercrete and clay-slip straw with a recycled brick base, and covered by a cedar shingle roof. This wall will then have information signs attached for visitors of CCAT campus.

Introduction[edit | edit source]

The Campus Center for Appropriate Technology, located in Arcata, CA needs an information kiosk. Constructed, with the help of CCAT and student volunteers, from stick frame and infilled with papercrete and clay-slip straw with a recycled brick base, and covered by a cedar shingle roof. This wall will then have information signs attached for visitors of CCAT campus.

Project Requirements[edit | edit source]

The goal is to construct a test wall that both suits the wet climate of Humboldt County, California and is useful to CCAT.

The Criteria for this project (and other projects of this scale) could look like this:

• ---
• Durability (How long are the materials specified to last?)
• Construction Time (What climate and material conditions limit time?)
• Complexity (Can construction be completed by the layperson?)
• Cost (How much will you spend?)
• Locality of Materials (How far will you go to find materials?)
• ---

These are basic criteria used to judge the design of this project. When each criterion is examined you can rank them according to importance. For this project, locality of materials, complexity, and construction time were very important factors because this project is one, part of an Appropriate Technology class, two, being constructed by students of HSU, and three, has to be completed in 15 short weeks. Ranking your criteria can be a powerful tool to assist in the timely and orderly design and construction of projects large and small.

Design[edit | edit source]

Overview[edit | edit source]

The foundation of this wall will be compacted soil with added gravel which will serve as the base for a 1ft tall layer of recycled brick layed in an interlocking pattern will sand mortar. This brick footing serves to keep natural plasters and infill material from coming in direct contact with the ground. The use of sand as mortar also allows the brick foundation to act as a wicking barrier helping to relive the wall of built up moisture through the seasons. The wall is framed by two driftwood logs and in-filled half by paper-crete bricks, half by clay-slip-straw, which is held in place by a recycled wood lath; and is covered by a combination of natural and lime plasters. The driftwood serves as a border for infill sections and to support a small a-frame pitched roof above covered with cedar shingles (seen to the right).

Specs[edit | edit source]

• 8 ft long, 4ft tall, 16in wide in a gentle S curve shape
• Roof dimensions, 9ft long 5.5ft high at peak, with 18in pitches on each side from peak
• Timber frame made from reclaimed timber and driftwood logs, simple 4x4s could work fine
• Recycled brick footing 1ft tall, 1ft wide, mortared with riversand
• One 4 by 4ft section in-filled with papercrete bricks mortared together with papercrete slurry
• One 4 by 4ft section stick framed with wood lath to hold infill of clay-slip-straw
• To be covered by earth/lime plasters by another student in ENGR 305 class

Costs[edit | edit source]

Testing[edit | edit source]

The first phase of the project after designing is to test CCAT's soil type and paper-crete mixtures. A soil shake test seen to the left proved that CCAT has the perfect clay for doing natural construction and will work well for our purposes of clay-slip-straw.

Next to test is the paper-crete mixture. The first test brick was made with a 1:2:1 ratio of paper to cement to water. This made a very soupy mixture that took weeks to dry, but, when it did it was as hard as concrete. After about 6 test mixtures the final ratio that seemed suitable was 3:2:3:1 of paper:Cement:Water:Sand. The use of less water and additive of sand made the bricks shrink less during drying and dry faster. The sand also increases thermal mass and helps with fire resistance. The resulting bricks (shown drying in a window to the right) dried solid like a very hard paper-mache and were also a lot lighter in weight than there would be concrete counterparts. The proportions that I used were what seemed appropriate for the Arcata area. More standard and researched recipes for paper-crete can be found from the Links and References at the bottom of this page or at Paper-crete Block Starter.

Purposed Timeline[edit | edit source]

Project in Construction[edit | edit source]

The gallery below contains pictures from the April 15 class work day. The pictures below describe the process involved with making paper-crete and clay-slip-straw.

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  Mixing clay found on-site for the clay-slip-straw using a power drill with a paint mixing paddle

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  The drill couldn't breakup all the small chunks so we did it by hand

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  The straw was mixed and turned till all just covered by the clay slip

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  The clay is then stuffed into the wood lath frame and ends up drying and looking like this ready to plaster.

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  It takes about 5 minutes of mixing with a power drill with a paint mixing paddle for wet shredded paper to pulp like this before adding cement

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  Blending paper shreds with Portland cement

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  This is the form we used to make the bricks used in the wall. When the bricks dry, they shrink, making the form easy to lift off

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  Here I am showing the class how to lay paper-crete bricks on the wall...

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  ...And again.

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  Natural building projects require a lot of community and group effort to make progress!

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  The finished paper-crete wall has divots that we made with our fingers in it to give the natural plasters something to stick into

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  The wall after a long hard days worth of work and almost ready to receive natural plasters

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  With the left over paper-crete from the day we made a large planter bowl. There are many uses for extra paper-crete. Use your imagination!

Conclusions and Reflection[edit | edit source]

Because of relatively good planning and readiness of materials this project was quite feasible and enjoyable. Were it not for the collective help of volunteers and the ENGR 305 class this project may have never been finished. Having now finished there are some things i would do differently in the future.

1. I would not have made bricks from the papercrete. The bricks all of slightly different size and shape and with different levels of moisture in them were not ideally suited for building a wall. Using larger forms that contain larger wall sections with tensile reinforcement like bamboo or scrap metal would have been a lot easier and required a lot less paper.
2. Just a note, paper-crete takes forever to dry in a coastal climate, especially if there is not enough cement in the mixture and too much water. Some applications I have researched suggest straining the paper-crete through a wire mesh to relieve it of a portion of its water helps it to dry a lot faster.
3. I would have liked to have experimented more with different types of paper in the mixtures I made. The shredded paper was so readily available it was all that I used. Word of mouth and research suggests that using different types of paper (e.g. newspaper, magazines) produces a significantly different consistency of paper-crete. So I would suggest experimenting to see which type is most appropriate to your project.
4. Even if your project is small, get others involved! The process of natural building can be fun and educational and most of all it brings people together with one goal in mind, to build something maybe new and exciting that is a hands on alternative to conventional building practices.

Links to Relevant Sites[edit | edit source]

• ArchitectureWeek-Building with Paper-crete
• Paper-crete Resource Webpage
• Papercrete.com
• Wikipedia on paper-crete
• Oikos Building Green Source

Brief Update 2016[edit | edit source]

With the Original Construction ending in 2009 this site was later used to create the Solar Charging Station in 2015. CCAT solar Charging station: [[CCAT Solar Charging Station]

References (Annotated)[edit | edit source]

Books[edit | edit source]

• Callahan, Tim, and Clarke Snell. Building Green: A Complete How-To Guide to Alternative Building Methods Earth Plaster * Straw Bale * Cord wood * Cob * Living Roofs. New York: Lark Books, 2005.

In this very complete 600 plus pages guidebook, Callahan and Snell demonstrate alternative building methods of cob, straw bale, earth plaster, cord wood and living roofs. The book is filled with history, applications, methods, and afterthoughts from the authors' firsthand experience with building all of the above listed alternative building methods. The book also provides step by step building processes with notes on basic construction of foundations, walls, doorframes, drainage trenches, trussing, and site preparation. Contains over 150 pages on proper calculations for soil, r-value, shrinkage, stick frame construction, and environmental specs. Thoroughly covers natural wall construction and earthen plasters in a manner that an amateur could understand.

• Norton, John. Building with Earth: A Handbook. London: Practical Action, 1997.

This handbook has practical applications for choosing whether or not earthen construction is appropriate or suitable for your site as well as an overview of how to build with earth. Contains a synopsis of the logistics for site appropriateness, soil testing, earthquake considerations, costs, resource use. Continues on to explain wall construction using the methods of wattle and daub, direct moulding, adobe, mud brick, rammed earth, and compressed blocks. The handbook continues to describe the same tone roofs, foundations and floors, and weather protection. Most of the experience the author has comes from earthen construction in Africa and China. This handbook has good overview of earth building, but lacks the attention to detail that a novice earth builder would need to begin construction.

• How to build walks, walls & patio floors, (A Sunset book, 170). Menlo Park, CA: Lane Books, 1973.

This book is a rather contemporary overview of building walls, walks, and patio floors. It explains wall building foundations and materials for use that include brick, stone, adobe bricks, and concrete cast. This book does explain to good depth the different types of patio and walk construction. It includes loose aggregate, concrete with many alterations to it including pebble mosaics, brick, adobe brick, tile, flagstone, and asphalt. Goes over most contemporary or western brick styles for walls and floors; this book requires a previous understanding of general construction to utilize properly.

Journals[edit | edit source]

• "Building with Straw Bales." Appropriate Technology Vol 32.No 4 (2005): 69. 13 Feb. 2009 <http://www.researchinformation.co.uk/aptearch/Oct-Dec 2005 p/html/Oct-Dec 2005 p 69.html>.

This short online journal sheds light on straw bale building. Written as an overview this article describes the advantages and shortcomings of straw bales. It speaks of straw bales life span, resistance to pests, fire resistance, and insulation properties. Gives a brief history of the long lived tradition of using straw in building around the world.

Web source[edit | edit source]

• "Cob, Earth bags, Cast Earth, Paperboard, and Straw-Clay Mixes - Real Goods Solar." Residential Solar Panel Installation and Solar Power Systems for Homes - Real Goods Solar. 15 Feb. 2009 <http://www.realgoodssolar.com/solar/p/Architecture-and-Building-Materials-Part-4.html>.

This web source taken from the Real Goods website provides brief overview and opinion of different natural building materials. Materials include cob, earth bag, cast earth, straw clay, and papercrete. A short history is included with the different methods as well as description of code restrictions and/or patent information. This page is a brief that contains little to no process description but does include links throughout the page to more in depth explanations and other literature on the various topics.

Contact Details[edit | edit source]

Myles D. med44@humboldt.edu Arcata, CA

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