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Bricks in Brazil – Eco-Friendly, Low-Cost and Cool

RIO DE JANEIRO, Jul 21 2010 (IPS) - Clay or earthen bricks could help to alleviate the housing shortage in Brazil because of the lower cost of brick buildings, while an innovative process for producing what are known as “ecological bricks” can avoid the environmental harm arising from more usual building materials.

In Pavão-Pavãozinho, a ‘favela’ (shanty town) on one of the hills in Rio de Janeiro, plans are underway for three low-cost housing blocks to replace homes at risk from land slippage, as well as those in the way of planned walkways or streets.

These works, part of Brazilian President Luiz Inácio Lula da Silva’s Programme to Accelerate Growth (PAC), are also being carried out in other Rio de Janeiro favelas and other parts of the country, with police pacification units and social programmes being introduced at the same time to fight drug trafficking.

At first glance these look like any other construction sites. But the walls are the colour of terracotta or red ochre: the same colour as the earth used to make the “ecological” bricks.

Francisco Casanova, a professor of civil engineering at the Federal University of Rio de Janeiro (UFRJ), is an enthusiastic advocate of this building material and has devoted the last years of his professional life to researching and developing it.

He pointed out that the technique is at least as old as ancient Egyptian civilisation. In Brazil, the first building using this kind of brick was built in 1942. In Europe, brick was used as a building material by the poorest in times of war and its aftermath, he said.

According to Casanova, who works at the Postgraduate Engineering Centre at the UFRJ, brick-making techniques have been taken up again and improved. New knowledge about mixers, additives and the compacting process is now used to increase brick quality and compressive strength.

“It’s all very advanced compared with the past,” said the engineer, who also does research on different low-cost building materials, like roof tiles made of wood or other plant matter.

Ecological bricks nowadays contain 50 percent earth, 15 to 20 percent sand and only 10 percent portland cement, as well as other ingredients.

According to Casanova, using bricks brings down the cost of a building by up to 30 percent. “After all, earth can be found everywhere,” he smiled.

Unlike traditional bricks, these do not need to be fired in a wood- or gas- burning kiln. This saves up to 90 percent of greenhouse gas emissions, responsible for global warming, that would otherwise be produced. And it also helps to prevent deforestation, Casanova told IPS.

The bricks are made in a factory in Magé, a municipality in the north of the state of Rio de Janeiro. Manufacturer Miguel Ángel Lasa designed a special machine to prepare the mix and press it into a mould.

There is no shortage of raw material. The first step in the process is the arrival of a truck loaded with local earth. The earth costs only 10 reals (5.55 dollars) per cubic metre, transport included.

Demolition rubble, crushed and sieved until it has the texture of instant coffee powder, is added to the earth. In the machine, additives for cohesion and strength are mixed with the earth, rubble, sand, lime and portland cement. Then the bricks are pressed to 90 percent of the mould volume.

The bricks are cured by hydration, simply by immersion in water, and left to settle for between seven and 14 days. The colour and odour of the bricks is that of wet earth. The factory smells of wet earth.

This type of material also reduces construction costs, Lasa emphasised. “In a traditional building, bricks are only used as a finish for the walls, but with this system, cement is only used for structural parts like load-bearing beams,” he said.

Another advantage that saves money is that plumbing and electric cable pipes can be fitted through the gaps between the bricks instead of having to break up the walls.

Bricks also provide thermal insulation and soundproofing, said Casanova. A 30-centimetre thick wall absorbs 56 decibels, he said.

“In regions where there are high temperatures, brick houses stay cool. We confirmed this personally in a completed flat in Pavão-Pavãozinho, on a day when it was 37 degrees outside,” he said.

As these bricks “give an attractive finish,” they do not require plaster or paint, just a coat of varnish or resin, the engineer said.

According to Lasa, demand for these bricks is increasing, and not just for low-cost housing but also for luxurious homes and hotels that invest in environmental quality.

In Casanova’s view, “political and economic interests” currently work against a mass return to using bricks for low-cost housing.

Brick buildings save not only on cement, but also on other construction materials like iron, wire, nails and plaster. This is not in the interests of either big industry or construction material suppliers, he emphasised. By his calculation, Brazil produces 50 million tonnes of cement a year, and 70 percent of that amount is used by low-income do-it-yourself builders who, like ants, patiently build their homes a little at a time.

Production is also a problem. For large construction projects, like the state PAC projects, factories need to supply about 10 million ecological bricks in less than 12 months, and they cannot meet this demand, he said.

The state Brazilian Institute of Geography and Statistics (IBGE) indicates that the housing deficit in Brazil is 7.2 million units.

The present Lula administration launched a programme aimed at reducing the housing deficit by 14 percent by the end of its term of office in December, a goal which experts say is unlikely to be met.