Why hemp is hot stuff

 

What do they do/Steve Allen, Hemp Building: No, this hemp isn't wacky tobaccy, it's an eco-friendly building material that provides high grade insulation. Bernice Harrison meets an expert

The energy awareness campaign around major kitchen appliances has been so successful that most of us are at least conscious of the energy rating of our new fridge.

We may or may not choose the A-rated model, but at least we're aware that such a thing exists.

According to hemp building expert Steve Allen, housebuyers in the future will also be doing an energy audit on the new house they are about to buy and builders will have to supply energy efficiency information that at the very least will tell buyers how much it will cost to heat their homes.

That's where better insulation comes in and he believes that the product he works with, hemp, will provide the sort of high grade insulation that eco-conscious people will demand.

Through giving courses in Kerry and Leitrim and through supplying hemp plaster products which he mixes himself, he considers himself a pioneer in the use of hemp as a building material in Ireland.

"In France, the use of hemp plaster is commonplace" he says, "largely because of its high insulation properties but also because it works so well in old stone buildings."

Adding hemp to lime significantly boosts the insulation properties, he says, and hemp can be used for flooring, plastering and in building entire houses.

"Hemp is mixed with hydrated lime and hydraulic lime in varying quantities depending on what it's going to be used for. A different ratio is required for flooring than for plasterwork."

The hemp used for building comes from the woodcore of the plant and is in chip form.

He mixes his own hemp products which he calls Hemphab and he describes hemp plaster for interior use as having the texture of "sticky muesli", which makes it attractive for self-builders who may not have the necessary skills to use the more commonplace plaster.

It can also be moulded into shapes, textures and finishes which again makes it appealing particularly for owners of traditional cottages or other period buildings. The plaster can then be painted with a breathable, eco-friendly paint.

"It's also been used in mainstream building," says Allen, who works as a project manager on eco-sympathetic building projects in Kerry where he has lived for 30 years.

He cites the example of a UK housing trust in Suffolk which built four houses, two with hemp, two without, and have published thermographic details showing how effective the hemp houses are in terms of their energy efficiency properties.

And yes, he has heard every single joke there is about hemp - there still is some confusion between hemp and marijuana.

"The hemp used for building is completely different from marijuana, they are totally different breeds."

The exploration of the use of natural materials in building is increasing all the time.

"It's all part of the whole energy audit," he says "it's a growing movement, it's going to happen."

The next course on hemp building will be a two day course in the Organic Centre in Leitrim, May 29th-30th.

To book tel: 071 9854338. Steve Allen can be contacted at 064 41747 or steeve@eircom.net

This column appears fortnightly