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Frequent Questions

What is ferrocement?

Standard construction cement, usually mixed with plaster sand. The standard cement is reinforced with more steel or fiber at a closer spacing than traditional construction. Reduced spacing yields uniform force dispersion and increases strength.

Ferrocement is also written as ferrociment, ferrocemento, ferrocimento, and ferrozement.

Are special tools required?

It is necessary to be able to cut steel and rubber gloves are necessary to protect skin from cement. A filter to avoid breathing cement dust is also a good idea. Otherwise, ferrocement is a labor intensive material which does not require pumps, compressors or even a mechanical mixer; cement and sand may be mixed on the ground with shovels, as was done in Rome thousands of years ago and is still done to this day. Never delay a project for lack of a mixer, pump or compressor; hand work is good quality and builds pride through solidarity, it's also peacefully quiet.

Why doesn't this website sell ferrocement or have advertisements?

The bulk components of ferrocement are sold at masonry supply stores. This website does have small quantities of specialized tools and materials which would have been convenient for this ferrocementer way back when, check our web store for, tools, hog rings and sculpture supplies

What about Building Permits?

There is nothing tricky about building permits for structures made of ferrocement or any other building material. Codes set the minimum standard allowed for a permitted structure. This means that most homes are built to the minimum standard the law will allow. All one needs to do to obtain a permit is to have a set of plans with a licensed architectural stamp of approval. ItŐs as easy as that. Although locating an architect confident with use of the material requires a little persistence it is not impossible.

Food for thought; ferrocement houses pay for themselves more than once per generation (low maintenance and insurance costs). Ferrocement tanks and reservoirs pay for themselves over and over by simply outlasting any other material.

What are the mixing proportions?

The following proportions are dry measure. Three sand to one cement, written as 3:1 (three to one). 2.5:1 is very rich, above 3:1 is less so.

Add water until the consistency is such that a line drawn with the index finger settles only slightly. Draw the line on the surface of fresh mortar, make it 2 - 3 centimeters deep. (1" deep). Examine the speed and fluidity of collapse along the line, also known as "slump." Excess water reduces ultimate strength.

Add dry materials in measured proportion if too much water has been used.

Why is it called ferrocement if it is standard cement?

Much steel rather than much concrete. Ferrocement is sometimes referred to as thin-shell concrete.

It is also called ferrocement because the rich mixture makes it hard, like iron. Fibers such as hemp, jute, flax and cotton can be substituted for steel and sand (see bio-fiber in website map). Fiber spacing is very small and the overall strength increase is significant.

How much time is required for it to dry?

Concrete does not dry; it becomes strong chemically, in 28 moist days. Four to six days seems to be a sufficient cure for the acrylic mixed with cement projects described in this website. If concrete dries before these periods it will not reach maximum strength.

Where can I learn more about ferrocement?

This website has a graphic shape section to illustrate engineering concepts with shapes rather than words. The tank construction section contains many techniques which will be useful to everyone, including artist and builder. Each section of this website illustrates or explains from the actual experience of many people. Please contribute additions.

The caretaker of this website has built five ferrocement houses, helped on five or six more, and is the product of a large rural neighborhood which experimented with ferrocement for over three decades. The region has frequent fires and earthquakes and techniques of ferrocement became part of the culture there in the 1950's. Older veterans inspected and encouraged construction during the earlier period. They knew ferrocement had helped conclude the war and were eager to assist an indigenous and vital young industry. Artistic and practical were blended. The goal was housing for everyone. Fire, hurricane and earthquake; no problem. Though ferrocement can be damaged by baking with high heat, it does not ignite and become fuel for the fire. The original Santa Barbara ad slogan was, "Ferrocement, won't rust, rot, or burn."

When the veterans grew old and retired, Late 1970's, they were replaced by college graduates from all over the country who had studied government science. Third generation neighborhood businesses were systematically destroyed by the new government employees who were not familiar with ferrocement and didn't realize or care that it can cost more to engineer than build. "Transition you out" was the approximate translatable term used by the most ambitious of the new government employees. "Some of you will be transitioned out," was the exact phrase in English.

The website caretaker is older now and this website passes on what was learned then so it is not lost to the future.

Where did this occur?

In the mountains of Santa Barbara, California. Sculpture, reservoirs, and boats were also products. Inexpensive sculptured houses were a local specialty that resulted in fire, storm and earthquake safe shelter.

How did ferrocement help terminate the second world war?

Barges, barracks, buried ammunition storage and many other constructions. It was during steel shortages of this period that US Navy engineers began to experiment and construct with bamboo reinforced concrete.

Why is ferrocement engineering so expensive?

Engineers use tables and formulae which summarize the compiled observations of what has stood through the test of time. This does require education and intelligence but does not require much original thought. Though the free and artistic forms of ferrocement structures are stronger than other buildings, they are complicated and time consuming to analyze on paper. Computerized structural element analysis automates this complexity but the software remains expensive. A confident architect can stamp ferrocement plans for permit approval with minimal calculations.

Where did ferrocement come from?

Greek fresco, Roman concrete and the sculptural wire and plaster technique from the time of Michelangelo Buonarroti and Leonardo de Vinci, with modern materials. The first definite ferrocement artifact was a tourist barge pulled along canals in the Amsterdam zoo.

Where is ferrocement going?

Organic fibers have once again become interesting as the cost of both steel and cement increases, space-age mud and wattle is one descriptive term used, on this web site. Use of organic fibers as reinforcement for cement is not a new idea, burlap and cement siding was used in the early 1900's, in California. Mud and bamboo are very durable, centuries-old technology, for example. And concrete is still called mud in the building trades.

Wood, steel and concrete will continue to increase in cost. The energy content of steel and concrete will make these materials more expensive. Forest depletion and cutting fees which compensate for the economic value of a living tree left standing will eventually drive the cost of lumber so high that wood houses will become rare. Ferrocement and its biological fiber form, which I call space-age mud and wattle, will become a primary building material of a future sustainable culture.

Traditional ferrocement enjoys unique economic advantages which will ensure it continues as a material chosen to create beautiful structures, reservoirs and interesting art.

Bamboo, wood and mud after a hurricane. It survived.