Will Anderson: The Green House

In the world of eco-building, the grass is always greener on the other side. There are so many products available, and so many eco-priorities to make sense of, that it isn't easy to come to a confident decision about which material or technology to use. If, however, you are literally contemplating grass as a building material, you are likely to be on to a good thing.

The most familiar use of grass in English housing is thatch. Different grasses are used around the country but wheat straw and water reed (Norfolk reed) dominate. The British thatching industry is flourishing but there are concerns that locally-grown materials are being replaced by imports from Eastern Europe and Turkey. A thatched roof provides a high level of insulation - and no other insulation looks this good - but is vulnerable to fire and insect attack. Fire is less of a problem if you bury your grasses inside your walls, the preferred approach of straw bale builders.

A straw bale house typically has a timber frame within which the bales are packed - a cheap and energy-efficient stuffing. The walls are often sealed and finished with lime render (see www.strawbalebuildingassociation.org.uk).

If these grassy options are unlikely to suit your domestic arrangements, you may still have space for the world's fastest-growing grass, bamboo. This remarkable plant is stronger than oak but you don't have to wait a couple of generations to harvest it. Bamboo forests are managed on a "constant cover" basis: three-year-old corms are cut, leaving younger shoots to mature. Like any spring pruning this cutting back helps to keep the plants healthy. The bamboo is machined into very long, thin strips which are then glued together to form a strong laminate. This can be used for flooring, furniture, kitchen cabinets and even worktops.

Last week I dropped in on Stephen Edwards, Brixton's eco-kitchen designer-maker ( www.ecointeriors-uk.com), who is building a kitchen with bamboo blockboard, which is stable, works well and has an attractive finish. Its colour is like beech: very pale but warmer if steamed during manufacture. Stephen buys his bamboo from Moso ( www.moso.nl), which is based in Amsterdam but imports from the Far East. Although bamboo thrives in many different climatic conditions,it is usually made in China, as are most UK consumer purchases. Other suppliers include www.ecoimpact.co.uk, www.bambooflooringcompany.com and www.ukbamboosupplies.com.

Grasses appeared in the world quite recently - 36 million years ago - and now numbermore than 10,000 species. They are particularly efficient photosynthesisers and so are able to thrive in very diverse habitats from dry African savannahs to tidy English gardens. Their unusually rapid growth gives grasses a sustainable edge over trees as they can be harvested regularly and still keep coming back.

Bamboo harvesting and manufacture ought to be a sustainable process but there is no independent scheme to guarantee this and concerns have been raised about over- exploitation of some species. Moso does its best to allay fears on its website - it is not stealing from giant pandas, for example - but this remains a problem. All in all, grass is green but not necessarily greenest.

Locally sourced timber is perhaps your very best bet for a sustainable building material but if I say this with too much authority I am sure to find myself up against yet another fence, admiring the lush grass beyond.

GREAT BUY
Lay yourself to benign rest in a woven casket from Bamboo Eco Coffins ( www.bamboocoffins.co.uk, 01795 472 262). The company has gained Fair Trade status. Prices start from £300.

GREAT WEBSITE
The International Network for Bamboo and Rattan, or Inbar ( www.inbar.int, 0086 10 6470 6161), pursues a global vision of sustainable bamboo forestry and harvesting.

w.anderson@independent.co.uk