10 February 2010: I got a sick feeling in my gut the other day after seeing a few dozen home-made cinder blocks drying in the sun. This sight ought to be a good thing – rebuilding has started. But it is not.

These concrete bricks – or, rather, the poorly made Haitian version – killed so many people during the big earthquake. I always thought that concrete was a simple thing: combine cement and gravel or sand and add water. But then I had a chat with one of the engineers Plan brought in as part of our emergency response. When made properly, concrete is strong. But it turns out that concrete is most definitely not a simple thing.

Quality issue

First, the quality of the cement is vital. Open up a bag here and the chances are it has been “stepped on” by adding silt or fine sand. Even if the cement is top notch, the temptation is to use too little cement with too much sand or gravel.

Even the gravel in Haiti is a problem. Instead of crushed rock, which features large and porous surface areas for bonding with cement, Haitians typically use smooth river pebbles. And then there is the curing. Ideally, concrete needs to be wetted constantly as it dries. Even putting a plastic tarp over the bricks will help it dry more slowly, making it stronger.

Construction danger

There are plenty of engineers in Haiti right now helping to design the rebuild. The lessons learned from using inferior concrete will hopefully be reflected in much stricter building codes, at least for commercial construction. But for the average person or small business owner, history threatens to repeat itself.

Lumber seems to be the best option. It is especially suitable for quake zones since it can bend and sway without crumbling. But as anyone who has flown over Haiti can attest, the country suffers from massive deforestation.

Green solution

Imported lumber for building is yet another item Haiti cannot afford. Cement takes a lot of energy to produce, with imported diesel fuel ultimately powering the massive kilns needed to make the magic powder. Lumber from sustainable forests must surely be a greener solution, perhaps even more economical. A pipe dream? Likely, but what rule says the unimaginable in Haiti must always be about bad things?

A more realistic solution would be to convince Haitians to abandon the multi-storey concrete boxes. Many of these now-flattened structures still hold corpses. The government of Haiti could rebuild the presidential palace in ranch-style – just a single floor with galvanised metals roofs. That would be leading by example.

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