Dunster plans zero-carbon homes built out of straw

Eco-housing champion Bill Dunster has devised an affordable method of building zero-carbon homes - using straw.

The man behind south London eco-development BedZed this week launched a joint venture company, StramitZed, with a firm that makes boards from compressed straw.

The boards are combined with timber and insulation made from recycled newspaper and made into cassettes which are used to build the homes. They will be marketed to developers, housing associations and self-builders.

Dunster says the boards can knock almost £20,000 off the price of building to level 6 of the Code for Sustainable Homes.

Chris Benson, architect at ZedFactory, said the firm was prepared for questions from developers concerned about the material. “You’re always going to get those questions about straw houses being blown down,” he said. “But we will have the manufacturer’s technical group on hand to answer questions.”

Benson said a developer of 80 homes in Plymouth had already expressed interest, and a prototype will be built at BRE’s innovation park in Watford.

The boards, which were designed 50 years ago by the Stramit Technology Group, are cheaper and slimmer than
the glulam boards previously used by Dunster.

Benson said the new deal will enable the firm to sell the parts for a four-bedroom house for £121,000, compared with £140,000 previously.

He added that a code level 6 house could be built for £135,000, including construction costs.

This is more than the £100,000 average construction cost of a code level 3 house, but Benson said when savings in utility bills and earnings from feed-in tariffs were taken into account, the code level 6 house was cheaper for the first time.

Benson admitted the system had similarities to the wattle and daub technique used to build homes in the middle ages. He said: “This is a completely modern day technology. It takes the basic materials behind what was being done so long ago and improves it.”