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Eco-friendly hemp house can slash heating bills

Posted on March 22, 2004

Hemp, the fibre taken from cannabis plants, has been used to build a house in Ireland for the first time.

The Old Builders Company of Birr, Co Offaly, has built the pioneering hemp-house in Clones, Co Monaghan, as a model of eco-construction.

The variety of plant from which the hemp is taken, cannabis sativa, has no narcotic qualities, yet builder Henry O’D Thompson, said the project had been the butt of many jokes.

“People generally say, set your house on fire and let the whole neighbourhood enjoy it!” he said. “Unfortunately, you wouldn’t get anything out of it at all.”

The building was constructed for environmentalist Marcus McCabe, who plans to run his EcoFlow ReedBeds company from the hemp house. He currently lives in a house a few yards away, constructed out of straw bales.

Tests have demonstrated the hemp house, compared with a conventional block cavity wall house, can average 2°C warmer for the same heat input, giving heat savings of between 10 and 20 percent.

It also ties in with the proposed carbon tax designed to reduce Ireland’s CO2 emissions. Most modern construction methods and materials, especially cement, are very high CO2 producers, but hemp, timber and lime reduce carbon dioxide levels in the air.

Mr Thompson said he had first used hemp in the reconstruction of old buildings. The woody core of the plant is used, which would otherwise be discarded once its outer layer had been used for clothing or ropes.

This is chopped up into woodchip, and blended with hydraulic lime and water to form a dry porridge, which can be moulded between timber frames much like concrete.

The builders went for a conventional plaster-style finish, to make the revolutionary house look as unremarkable as possible.

Copyright © 2004, Irish Independent. All rights reserved.