Weed walls for Greens councillor

Greens councillor Brent Hoare has joined the hemp house movement.

He is in the process of building his new 130 square metre double storey home made of hempcrete - one of about half a dozen to be built in the Mountains in the past five years, with others in Hazelbrook, Medlow Bath and Wentworth Falls. There are also homes in Hartley and the Megalong.

Hemp fibre dates to Roman Times, but hemp and lime, as it is currently used in building, was first used in France in the later 1980's to renovate half timbered houses built in the 1500's. Now a wave of builders are renewing interest in the sustainable building material.

Cr Hoare said hemp is a fire resistant and ideal for construction in fire prone areas.

"It's been a dream of mine to build a home from scratch and I wanted to make it in the most environmental way practical. We are all living in a much more dangerous world and the fire resistant qualities of hemp really recommend it."

The price is about the same as a brick veneer home, but heating and cooling will be much cheaper. As well as all its sustainable features, hemp also locks up carbon dioxide in the build. On an almost 40 degree day in January when the Gazette visited, it was already cool inside the half built structure.

The insulation values are very high, and as well it has good thermal mass which helps to maintain an even temperature" he said.

Cr Hoare assisted on a hemp house build about three years ago by award winning designerKirstie Wulf of Shelter Building Design.

"It sounds really wacky. People make jokes about smoking it, but it's quite conventional [in its structure]," he said.

Cr Hoare is building the house while on his high school teacher holidays and between stints with the Rural Fire Service. He and his partner, social worker, Lisa Clement have had the assistance of "two particularly wonderful WWoofers (World Wide Opportunities on Organic Farms)" as well as friends, family and many in the community.

"We had 17 people over six days and we got the bottom floor done. It's not highly technical, anyone could learn it."

WWoofer and gap year student from New York, Mav Hopkins, had no experience in building, but was "intrigued" by the idea of building a hemp walled home.

"It was so different compared to the rest of the hosts."

She has worked on the project during the fire season and said her parents were relieved when told her host was a volunteer firefighter.

Cr Hoare has had regular community workshop days, including over the Australia Day long weekend. University professors and students have been some of the people interested in the process and eager to help.

Ms Wulf said when the Gazette last did a story on her hemp build, she had a student from Denmark get in contact who has now started working on hemp home awareness in her own country. The work of Ms Wulf has become so popular she is being asked to speak at international events about the product.

The material has been praised for its insulation qualities, it buffers temperature and humidity and prevents damp and mould growth.

The structure's timber frame foundations are the work of builder Chris Clarke, who said "not much needs to change .. it's just a different way of insulating [with] the thickness of the walls ... and different finishes".

Ms Wulf said hempcrete is rated to BAL flame zone (the highest bushfire rating) and hempcrete has been approved by Blue Mountains Council for use in a BAL FZ rated property to be contracted at Blackheath.