To hemp’s proponents, it’s something of a wonder shrub. It requires no herbicides or pesticides and can grow faster than almost any other plant. In Irish conditions, it would take about four months to grow the one hectare of the plant needed for one house.

Unlike many crops, it enriches rather than damages soil. It is as robust as cotton, as warm as linen and more durable than either. As a building material, it is stronger than wood or concrete. It is also rot-proof, fire-resistant, lightweight and unpalatable to vermin.

So, why the reluctance to experiment with this potentially revolutionary plant? It seems that there’s more than a hint of reefer madness about the authorities’ attitude to hemp.

Made from cannabis sativa, hemp is a close relation of marijuana, the illegal drug. The difference is that commercially grown hemp contains almost none of the psycho-active property, THC, which creates a “high” when smoked. Studies show that marijuana typically has a THC concentration of between 2% and 5% with stronger strains measuring as high as 22%. In contrast, industrial hemp contains only about 0.3%.

“The hemp we used on the house has almost no narcotic value. You probably wouldn’t get a buzz if you smoked the whole building. It’s like the difference between drinking a shandy and a bottle of whiskey,” McCabe says.

Henry Thompson, the builder that completed McCabe’s house, believes that it’s only a matter of time before the plant becomes an accepted building material. “The only drawback is obviously the expense but that problem can be solved. It was used in Ireland for hundreds of years before the industrial revolution and our climate and conditions are perfect for large-scale hemp production,” he says.

So, what is hemp like to build with? “It was a dream, very user-friendly and adaptable,” according to Thompson, who runs the Old Builders Company in Co Offaly. “I started working with hemp two years ago. We specialise in conservation work and found that hemp mixed with water and hydraulic lime was ideal for insulating and damp proofing old stone buildings. It’s an extremely breathable material, so any house built from hemp is guaranteed to be healthy,” he says.

Still barely legal in Ireland, the international community has mixed views of the plant. In America, you have to apply to the US Drug Enforcement Agency for a licence to cultivate commercial hemp. Many people have tried but not one application has yet been approved. In 2001, the agency banned all food products containing even traces of hemp.

In contrast, hemp was reintroduced to the UK in 1993, to Germany in 1996 and to Australia and Canada in 1998. In Europe, France is the biggest producer, and it is commonly used as a building material in the countryside. The hemp used on McCabe’s house originated in France.

In Britain, the residents of two hemp houses built in the Suffolk town of Haverhill by social housing provider Suffolk Housing Society are delighted with their new homes, if a little bored by all the wisecracks. “It’s warm and dry and comfortable, and it has a lovely rustic feel to it, even though it’s a new house,” resident Jessee Mulcock says. She was also surprised to find that her house had better acoustics and sound-proofing than anywhere else she had lived before.

Thompson says: “In the scheme in Suffolk, two identical houses were built side-by-side — one from hemp and one from cement. A thermal picture was taken of both houses at night and the difference was staggering.

“The conventional houses were glowing because they were losing so much heat. The study found that the hemp house was on average two degrees warmer throughout the year. That translates into heat savings of between 10% and 20%.”

Following the success of its first project, the company has started a second hemp house in Co Wicklow. “The first one proved that it was viable, so we’re expecting much more interest now,” says Thompson.

www.oldbuilders.com, 0509 21133

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