Can any straw be used to build a straw bale house?
The answer is not quite as cut and dried as it might first seem. There are indeed many factors that make a bale suitable for straw bale construction. While it is possible to purchase usable straw from the local farmer, and sometimes at an extremely good price, take care when checking the straw. Be clear when specifying your requirements to the farmer if he has not yet cut and baled the straw, which often is the case when acquiring straw in December and January. To simply find an ad that says “straw for sale” is not necessarily the solution (as we found out the hard way, when bought a load COVERED in chicken poo).
How many straw bales will I need?
The quantity required will vary from house to house, depending on the size of the house and the number and size of the windows. On average, it seems that most houses would have 300 to 500. The house Brian built in Heathcote Victoria is a two-story residence of about 22 squares and required 520 bales. The normal semi-trailer will carry 500-520.
What PPE (Personal Protection Equipment) will I need?
Heavy-weight pants and long sleeve shirts are essential for working with straw bales, unless you don’t mind looking like a cactus attacked you. The bales are scratchy and can give you many tiny splinters unless you wear protective clothes and gloves. You need protective goggles and rubber gloves for rendering, and always wear hardhats on site.
How much does it typically cost to build a straw bale home?
There are so many variables that this is a bit like asking “how long is a piece of string?” If you were to source second hand materials and forgo luxury finishings, a very rough estimate would be $600-$700 per square metre (for a straw bale home built on a timber floor, with reasonable soil).
For a home built from all new materials, you are looking at around $1000 per square metre. This does not include high-end finishings which can blow any budget out of the water.
How often are the practical workshops held?
We hold practical workshops several times a year, depending on numbers, in Inglewood Victoria.
Are straw bale homes more at risk in bush fires?
No. The CSIRO conducted a study in 2012, wherein testers subjected a straw bale house to a fire at over 1000 degrees Celsius. This concluded that straw bales homes are a viable option in bush fire prone areas.
Where do I hire a render pump from?
Mark Beedle has a great render pump for hire and will be happy to look after you. Call him on 0411 042 363, and tell him Anvil referred you.
Can you recommend architects or draftsmen to help design our house?
If you enroll in our online training course you then become one of Anvil’s clients. Subsequently you have access to a number of services we provide. These include design and drafting. The course teaches you everything you need to know about building your own straw bale home.
Are concrete floors more efficient than timber floors, because of thermal mass?
While concrete floors are sometimes necessary, well prepared timber floors can be equally, if not more, efficient than concrete floors. An enclosed sub-floor, with insulation between the floor joists, minimizes air flow and addresses any efficiency issues.
Can you do a straw bale retrofit on an existing house?
Absolutely! It is easy and cost effective. Additionally, if you follow our guidelines you cannot pick it from a new straw bale home. You get all of the same benefits of insulation and appearance. It is simply a matter of extending the foundation with additional stumps and floor to support the straw bales. The primary complication is regarding the roof, as it is often necessary to extend the eaves of the house. However this is not really a big challenge.
Can I get someone else to build my straw bale home, instead of building myself?
If you were to get a builder to build you a straw bale house it will cost about the same as a brick veneer home. However, there are huge savings to be made as an owner builder. Straw bale houses are very owner builder friendly, given that you have the information to guide you through the process. Building yourself also means you pick your hours.
Are straw bale walls susceptible to vermin?
No more than ordinary walls. Straw is made of cellulose which is not an attractive food source to rodents. Seal the walls with a minimum 35mm of render, and it is unlikely that they would make their way into your walls. Just cap the tops of the bales with render, to eliminate any sneaky access points.
Which method is better - load bearing or post and beam?
We recommend infill, largely due to personal experiences. You erect the walls before the roof, using the load bearing method. This means that if there is a period of heavy rain, the integrity of the unprotected walls is compromised. This can cost an owner builder time, money, and unnecessary stress.
Can I hang photo frames and attach other things to straw bale walls?
Yes! For most picture frames you can simply drill a sizable screw directly into the straw bale wall, as the screw will twist into the straw and become anchored. For anything overly heavy, such as a wall-mounted TV, you can hammer wooden blocks into the straw bales and render around them.
Could the straw bales break down in the wall?
Properly constructed walls will not break down. The render keeps the air and moisture out of the walls, effectively sealing them up tight. Take care to protect the straw bale walls in wet areas (kitchen, bathroom and laundry), and plan wide enough eaves.