Over the Easter break, I made the trip to a small country town called Ganmain (about an hour away from Wagga Wagga) to take part in a straw-bale building workshop. For a long long time I’ve been itching to build my own eco-home, but have never even set foot on a building site and wouldn’t know where to start.
I found this course after a small trawl on the internet, and figured that if I don’t do it now, I’ll never get around to it, and I am SO glad that it did! Run by husband and wife team Huff ‘n’ Puff (aka John and Susan Glassford) the course went over 5 days (you can do less, but you miss out on the rendering, which is very important.) I met some lovely people too.
One of the things that attracted me to straw-bale (apart from the brilliant UK show Grand Designs) was it’s brilliant insulation properties, low environmental footprint and excellent fire-resistance (once rendered.) It seems that many straw-bale homes don’t need a concrete slab built, but can use a simple rubble trench and concrete bond-beam instead (this will depend on a geo-tech site report and the design of the house though.)
Here are some photos:
The bales are delivered to site and inspected. I was surprised to find out that bales come in different shapes and sizes, so you need to know what you’re getting before you do your design (widths tend to be the same though.)
I was a bit nervous at first as we had to do some basic carpentry, of which I had next to no skill. John taught us what we needed to know and before long we were using the drop-saw like we were pros! We made the bottom and top plates (these are what holds the bale walls) as well as window and door frames. Actually fairly simple, but there are a few tricks and things to know, such as how to brace these and square them properly. After doing it, it seemed straight forward.
There were quite a number of half and broken bales which had to be restrung and measured. Sometimes a particular size is needed so these bales are sprayed with their length for easy identification.
Here we are making the top plate as an exact copy of the bottom plate (the three ‘layers’ that can be seen in the photo, from bottom-up are: concrete bond-beam, bottom plate, top plate.) The bottom plate is filled with pea-rubble and sand. There are also threaded rods poking up that have a cap on to protect from the elements – these are used to compress the wall (hopefully covered later.)
The door frame and window frame can be attached to the bottom plates, with a little bit of squaring and support. The two long bits of wood (called ‘stiles’) will penetrate the top plate and will need to be cut off.
Before the walls can be put up, a corner brace needs to be put in place so that the bales stay roughly in place. These were already made, but seemed simple enough to put together if needed.
Earlier, I said that the top plate is the same as the bottom, but it’s not quite. There are steel plates that need to be recessed into the top plate. A pair of threaded rods will go through each steel plate and attach to the bottom rods that were protruding from the concrete beam so that the walls can be compressed. The reason for the recess is that another strip of plywood will be nailed on top for waterproofing, and so space for the nut is needed.
I’ll write another blog soon detailing more steps….