Built with soil: Earthbag construction technology finds home in Kericho

An exterior view of the Earthbag house in Kericho still under construction. PHOTO | COURTESY

What you need to know:

  • Earthbag technology involves filling sacks with soil and then stacking them together like soldiers do when building bunkers to ward off attacks.
  • The bags used are the onion-net type while the dome shape of the house means that the house does not require a roof, greatly saving on cost.
  • Chicken wire mesh is then added to provide additional strength before concrete is plastered.

When most people decide to put up a decent house, they go for brick and mortar, the most conventional construction materials. But a couple from Kericho has gone against the grain by opting for a non-conventional method of construction for their country home.

The three-bedroom house for the family of five is being constructed using earthbag technology, a method the designing architect, Mr Francis Gichuhi, says is the first of a kind to be used to put up a residential home in the country.

To put it simply, earthbag technology involves filling sacks with soil and then stacking them together like soldiers do when building bunkers to ward off attacks. Chicken wire mesh is then added to provide additional strength before concrete is plastered.

“The bags used are the onion-net type while the dome shape of the house means that the house does not require a roof, greatly saving on cost,” says Mr Gichuhi.

Asked the reason behind using onion bags and not any other type, the architect says, “The perforated and net nature of onion bags produces friction between the layers, which is important in keeping the walls intact and preventing sliding.”

This particular house features three bedrooms and a kitchen. All the rooms can be accessed from the living room, which also houses the dining area. The kitchen is also accessible through the back door. Of the three bedrooms, two are en suite with the remaining bedroom having a toilet only.

“This is the first time I am seeing this concept despite having headed several construction projects over the years. It is such a joy to have been able to execute instructions from the architect and pull it off,” said Mr John Kibet, the labour contractor.

The couple declined to speak to the Nation, citing their need for privacy.

A RARE SIGHT

In the quiet Masariat Village, on the outskirts of Kericho town, villagers are more than impressed, with one or two stopping by to inquire about cost and admire the architecture from time to time.

“This is excellent work you have done John,” remarked a neighbour, careful not to interrupt our interview with the contractor. Even builders on the site seemed inspired by the house they were taking part in constructing, and often times spoke of what they would include in their own houses when they get to build them.

Such a house comes with a number of advantages. For instance, Mr Gichuhi says earthen buildings have superior thermal qualities compared with other buildings.

“They are warm at night and cool during the day, creating a very conducive living environment inside the house, especially for elderly people,” Mr Gichuhi says. “On the lowest scale of heat conservation are iron sheet houses, which tend to be too hot during the day and really cold at night.”

Francis Gichuhi an architect and founder of architectural firm A4 Architects1. PHOTOS | DELFIN MUGO

COST-EFFECTIVE

Perhaps the greatest advantage of this construction method lies in the cost-saving aspect, largely because the primary construction material, soil, is readily available and free.

“A normal brick and mortar three-bedroom house would cost more than Sh3 million to construct while this one will cost Sh1.1 million, making it much cheaper, especially for someone who can get the soil free of charge. That notwithstanding, the fact that this house offers the same quality of indoor temperatures, security among other issues as a stone house,” says Mr Gichuhi

Even though red soil is the most ideal type of soil for earthbag construction, Mr Kibet says, any type of soil including black cotton can still be used.

“Black cotton soil, however, is likely to disintegrate after sometime and therefore you need to use cement as an adhesive to hold the soil together,” he offers.

PRECISION COUNTS

Construction of the domes is the most challenging as it has to be done to precision, with the radius from the centre of the dome reducing with every layer of soil.

Ideally, the basic purpose of a roof is to protect a building and the people living inside against external elements such as cold, heat, storm, hail, rain, snow, and noise. But with technological innovation, roofing has become a big deal and most homeowners have found themselves breaking the bank in order to have the most visually appealing roofing. With earthbag houses, this need not be the case

“The roof appears hidden from the ground, meaning you would have to be on higher ground to get a glimpse of the roofing structure. This also means you can go for the usual corrugated iron sheets as the house’s appeal is not dependent on the type of roofing,” offers Mr Kibet.

Additionally, the stacked-up soil bags take the place of bricks, another significant cost-cutting measure. For example, only the porch of this house is built using bricks, though it did not consume more than 150 pieces.

“The couple asked for a cheap and practical method of construction. They also wanted something that would give their house a unique shape. Seeing the abundance of soil in the village, I advised them to consider earthbag technology,” says Mr Gichuhi.

The sunroof in the living room and dome tops made of transparent glass are some of the interesting features on this house, which the architect is counting on to give the house a unique aesthetic appeal, besides allowing in sunlight.

It is easy to see why this family, which spends most of their time in Nairobi, would opt for such a model for a country house — it merges the modern and the traditional, and in a way brings the house closer to nature.

BLEND OF CULTURE

Besides the many amenities available in a modern house such sunroofs and master en suite bedrooms, the house still captures the traditional aspect brought out in the dome shapes that resemble traditional mud-walled huts, and the feeling one gets when entering a room from the living area; as if one is getting into a cave (in this case a dome made of soil covered in cement).

Mr Kibet revealed that construction of this house in Kericho began in December last year and will be handed over to the client very soon. He said building such a house takes 12 weeks.

Earthbag housing is common in South America’s Ecuador and Brazil. The late Nader Khalili, a world-celebrated architect and founder of the Cal-Earth Institute, is credited with popularising this method of construction that has also caught on in parts of the US, such as California. An earthbag structure has a lifespan of a 100 years.