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close this book Handbook for building homes of earth
View the document Table of contents
View the document Foreword
View the document Chapter 1: Introduction - Types of earth houses
View the document Chapter 2: Soils - And what can be done with them
View the document Chapter 3: Stabilization of soils
View the document Chapter 4: Where to build
View the document Chapter 5: Foundations
View the document Chapter 6: Lightweight roofs
View the document Chapter 7: Preparing the soil
View the document Chapter 8: Making adobe blocks
View the document Chapter 9: Making pressed earth blocks
View the document Chapter 10: Making walls with earth blocks
View the document Chapter 11: Making rammed earth walls
View the document Chapter 12: Roofs for earth houses
View the document Chapter 13: Floors
View the document Chapter 14: Surface coatings
View the document Suggested references
Open this folder and view contents Appendix

Chapter 13: Floors

The most desirable type of floors for an earth house is, of course, a concrete slab, a wood floor or a floor surfaced with cement tile or ceramic tile. However, in some areas where good sand and gravel are not available for concrete, and where wood is scarce and commercially made tile cannot be obtained, an earth floor can be substituted. Properly compacted earth or high strength stabilized earth tile will make a reasonably durable floor. Extra stabilizer is required if floors are to last a long time, because floors get the hardest wear of any part of the house. Even the most primitive dwellings have some type of oil or fat worked into the soil as a stabilizer.

TYPE OF SOIL FOR EARTH FLOORS - For earth floors, use the same soil you use to build your house but add extra stabilizer.

The floor must be able to withstand scrubbing and must be tough and durable.

Lime and portland cement make the best stabilizers. Emulsified asphalt will make good floors but the dark color may be objectionable. Wood ashes and even animal blood have been used.

TAMPED OR RAMMED EARTH FLOORS - Before making the earth floor, it is necessary to remove all organic topsoil, or at least down to 6 to 7 inches below the level of the finished floor. Then compact the top layer (3"-4") of existing soil with a tamper before the floor material is placed.

In areas where swelling soils are damaging to buildings this ramming should be avoided. Untamped soil will swell less than tamped soil.

The first layer above the existing soil is filled with about four inches of clean sandy or gravelly material. The purpose of this material is to stop moisture that may rise up from the existing soil. The sandy material should be well tamped to strengthen it and to keep it from settling. If the existing soil is the swelling type, use about 6 inches of sandy material.

The floor is laid above the sandy course. Place it in two layers each about 1½ inches thick. The lower layer can contain less stabilizer than the top because it does not get any wear. The soil should be carefully rammed into place. Be sure the moisture content is correct. Check it using the method described in Chapter 2. When you finish tamping, level up the area by scraping or tamping high spots.

The final finished floor layer is placed next. This layer should contain enough stabilizer to make the cured surface difficult to scratch with a nail. This might require 2 to 3 times as much stabilizer as might be used in earth walls. Test your mix by making small rammed earth test blocks just as you would for a rammed earth wall. After the test blocks have cured check them for hardness and water resistance.

After tamping the top layer, smooth out any tamper marks and then cure the floor for several days.

Portland cement and lime-stabilized floors may be cured by sprinkling the floor or putting wet sacks on top of it. At the end of the curing period, a thin portland cement slurry made from cement, water and fine sand may be applied to the floor to seal any cracks and waterproof it. Certain oils will do the same job.

Don't walk on the floor until it is hard.

TILE FLOORS - Pressed earth tiles may do just as well as rammed earth floors. They can even look nicer, particularly if you make tiles from several different colored soils. The CINVA-Ram or any other block-making machine that makes; 1½ to 2" thick tiles can be used. Use enough stabilizer in the soil so the cured blocks are difficult to scratch with a nail. Make test tiles to check the stabilizer content.

Stabilized tiles should be moist-cured for 7 days and then dried in the sun before placing them. Prepare the floor area the same way you would for rammed earth floors. It is very important that the sandy layer be level and well-compacted before placing the tile. If it isn't, the floor v ill be rough and unsightly.

It is better to mortar tiles in place with a mortar of sand, portland cement and water. Carefully smooth the mortar joints to keep from having grooves in the finished floor. Tiles can be laid without any mortar if they are placed closely together. They may rock a little or come loose, but it won't hurt if they are put back right away.

Since cured tiles are used, the floor can be walked on as soon as the joints get hard. This will take 2-3 days. Oils or waxes may be used to seal the top surface of the floor. Tallow has been used, and if applied hot, beeswax may also be quite suitable.

HEATING THE HOUSE THROUGH THE FLOOR - You can heat your house by heating the floor.

This idea is used in the United States and other places in the world(Korea, for example) with tunnels under the floor. These tunnels carry heat from a fire which is built at one of the openings.

This method of heating should not be attempted unless you have someone experienced to show you how to do it.