Building with Lime
There is a renewed interest in using lime, gypsum, clay and earthen plasters for strawbale and other natural material houses. Many people know that lime has been used for over 5,000 years, most notably by the Romans to make mortars and plasters. In the cold northern regions of Scotland and Wales lime plasters protect even stone walled builings from harsh weather and fierce rains. Lime "harling" ...a thrown lime plaster...is used as a sacrificial coating to keep water from cracking and damaging stone walls and mortar joints.
When lime is used on strawbale and earthern walls it provides a vapor permeable skin which allows moisture in, and out again, before it can seep to the wall and cause damage. And lime offers many more advantages.

Alternative builders are choosing lime-sand plasters instead of Portland cement based plasters, and achieving excellent results. Cement, while cheap, and popular in traditional stick-frame building, cannot compete in performance with lime.
The National Lime Association recommends a small portion of cement for guaging in a 1:2:9 cement:lime:sand, mortar or plaster. Many builders are eliminating cement altogether. Some are using quicklime (when it can be obtained), slaking it, and adding Prickly Pear Cactus gel (Nopal) to mixtures as a binder. Most builders can use hydrated lime soaked in water to make a plastic, workable mix. Simple, old fashion limewashes are becoming more popular too.

Straw bales perform well with lime based plasters and earthen plasters.

Lime plasters dry more slowly, gaining strength over time, which is their advantage for owner-builders. Lime in building use is very forgiving, and can be reworked for days after placement, unlike cement which is meant to set-up in hours, and cannot be altered at all once mixed.

This straw walled house has been give a two coat plaster with lime and fine straw.

Straw bale plasters use a fairly standard mix recommended by the NLA for basic plastering. Finely sifted straw, special nylon fibers, clay, mica, marble dust, dung, iron oxides and other colors, plus additives can be used with great success.

All About Lime: A Basic Information Guide for Natural Building...by Charmaine R. Taylor. Many questions are answered in this book on using lime and gypsum. Explained are slaking quicklime, hydrated lime, the differences between Type S and N, when to use each, how to make a natural cement, dry up mud on the worksite, and stabilize soil for earthen bricks (for Cinva Ram block presses and others). A complete interview with straw bale plasterers "Our Helping Hands" is included. Lime is an amazing, very versitile building material which can be used on the ground, and in foundations, walls, for plasters, mortars, cements, garden and land tilth, and in the waste/septic system. Chapters on plaster and mortar give recipes and current recommendations on application and use. A complete history details how lime was used for building, and how it can be used again for an earth friendly altenative to Portland cement. Technical articles from several resources, and Harry Francis, lime consultant, are included for a thorough overview of lime useage. Lists lime manufactures, resources, websites, other booklets, bibliography. Illustrated, photographs, 52 pages, booklet. #1009...$13.00... ORDER HERE

This photo shows the wild colors in plaster which can be achieved for walls.

Questions? email: tms@northcoast.com
© Copyright 2000 -2008 Taylor Publishing, Cutten CA . This page updated 4-08
Grateful acknowledgement to Gary ( Prasad) Boudreaux of Our Helping Hands for use of the photographs.