Fibers from flax and hemp can make building practices much more environment-friendly, research by ABN Amro has found.

Flax and hemp are versatile crops that can be widely applied in insulation but also have their use in cattle feed, paper and textile production. “Nearly every part of the plant can be used,” the researchers said.

Hemp and flax are also good for the soil because they store CO2 and do not need extra fertilising or water.

For the plants to be used on a large scale crop yields will have to be increased, for instance in Eastern European countries, the ABN Amro researchers said.

It is not likely the Netherlands will find room for the cultivation of the plants and the researchers emphasise that European cooperation is key.

“You need one hectare of hemp to insulate a single house. But if the weather has been wet you will need two hectares,” Cor van Dijk of circular building advocates Building for Good told Nu.nl.

Some 50,000 hectares of hemp and flax would be needed to make houses in the Netherlands more sustainable, he said.

So far large scale tests to make sure hemp and flax do no increase fire risks have not be done. “Several products containing the plant material have been tested and scored well,” ABN Amro researcher Paul Bisschop said.

Asked whether hemp fumes from a house caught on fire would make neighbours high, Bisschop said the thc concentration in hemp is very much lower than in marijuana plants.

Straw

Dutch developer Ballast Nedam is turning to straw in its efforts to find new ways of making homes both more energy efficient and better for the environment.

Straw, which would be burnt or used as bedding for animals, is being used as insulation material in a terrace of eight new homes being built in traditional Dutch style in Heeze, near Eindhoven this year.

The homes will be more than 90% bio-based and will be energy positive, meaning they will supply more electricity back to the grid than they use, Ballast Nedam says. They will also absorb some 90 tonnes of CO2.