You could be forgiven for thinking the idea of building a straw baled house to be rather primitive. The fact is that using one of the most traditional of building materials – straw – when in its baled form: makes an incredibly good insulator, is very flexible in the designs that can be built with it, used properly straw bales are both strong and fire-resistant, they’re much cheaper than bricks and finally are incredibly environmentally friendly.
With so much talk about Carbon Dioxide in the atmosphere and the need to reduce our Carbon ‘footprints’; using straw bales when building something makes eminent sense.
Straw is the stalk and in effect a waste material from naturally growing cereal crops. With the exception of special straws that are used in thatching; with no nutritional value straw is a waste product as far as farmers are concerned.
What isn’t used for animal bedding is often burned – pumping Carbon Dioxide into the atmosphere quite unnecessarily. If the baling is done manually no unnecessary Carbon Dioxide is produce – and even if done mechanically the amount is formidably lower than that required to make bricks.
In using straw bales you’re actually locking away Carbon Dioxide for decades to come. Straw bales also have formidable insulating properties compared to brick, meaning that you’ll need less energy to heat your home, which will also save you money on fuel bills.
Safety of Straw Bales in Home Construction
Using straw bales in the construction of a house is perfectly safe, providing certain guidelines are followed; which is no different to building with any other material. The thing to remember with straw bales is that they are incredibly densely packed. It is this compactness that not only gives them structural strength – but also protects them against the things that most people worry about in just about any home, regardless of the construction methods used.
So, what about the risk of fire? For combustion to occur air, or more specifically the Oxygen in air, must mix with a fuel and heat source. Quite simply straw bales are that tightly packed that air cannot circulate through them and, therefore, they do not contain enough Oxygen to support combustion. This lack of Oxygen in straw bales also retards their decomposition providing they don’t become unduly wet, meaning that you don’t need to worry about them suddenly rotting away.
As stated earlier straw is a waste product from cereals, it has very little nutritional value or farmers would put it to a better use than animal bedding. With no nutritional value it’s of no interest to vermin. The same as with any building material vermin could be attracted to nest in or near it; but again as with any other building material this is avoided by good building techniques and, when completed, basic cleanliness in your house-keeping.
Straw Baled Construction and Dampness
One thing to be on guard against with a straw baled house is moisture seeping into the straw bales. The best protection against this at the initial building stage is to have a good concrete foundation for them to sit on. This means building the foundation at least 150mm (6 inches) above ground level, having the best damp-proof course you can find/install and making your roof overhang the walls by at least half a meter, or a couple of feet.
After that it’s a question of regular maintenance; exactly the same as any building, fix any holes in the roof, walls etc – immediately. Also, giving the exterior wall rendering a regular lime-washing will help guard against any damp seeping through the walls.