In this case though, we are talking about rocks. The heavy, misshapen and sometimes crumbly variety!
It all started with Murrumbateman Field day a couple of years ago. If you have never been to a field day of this kind, it’s worth a visit. The next one is on the 17th and 18th October.
Anyway, one of the exhibits was by the Dry Stone Walls Assoc of Australia Inc (DSWAA) and they were demonstrating how to build a dry stone wall. We have plenty of rocky outcrops on our property which is why it caught our attention. Mr D and I had never considered a stone wall put together without any sort of mortar.
After much discussion with the guys doing the demonstration, there came a mention about a workshop near Burra (which is just up the road from us) that was coming up and would we be interested? Or more to the point, would Mr D be interested?
So on the 3rd and 4th November 2012, Mr D headed off to participate in a workshop to build a dry stone wall. When he arrived home Sunday evening, he was shattered. He was covered from head to toe in dust, could barely walk due to exhaustion, body aching all over however a smile that told me it had been a great experience. Did I mention the dust? His hair had changed colour and every step he took resulted in a cloud of dirt raining down on the floor.
Mr D was very keen to try out his new found skills so began collecting rocks. And so the first wall was started. Mr D is going to discuss the process.
The first dry wall project was selected to be a fairly small extension to our garden area where the fall of the land meant that the garden was quite small. The dry stone wall was to be a retaining wall to allow the garden to be extended.
The top 75mm to 100mm of top soil is removed to provide a firm base without roots and grass.
A simple frame is placed at each end of the wall to act as a guide for the long sides of the walls. String between the frames sets the “lines” similar to a brick layer when building a house.
As the wall rises, the string is lifted to provide the next line (now narrower than before) for the next layer of stones. I used tomato stakes, but a larger wall would need something like reo bars to give the length and strength needed.
Large stones are used as the foundation stones for the wall. These stones were very heavy, and were wheel barrowed and dragged into position. A crow bar was used to jiggle the stones into position.
The centre of the wall was filled with heart stones to keep everything steady and to provide base for the next layer to be laid on top.
At about half way through, stones were placed across the wall (from side to side) to help bind the wall together. These stones were longer flattish stones that, when found, were kept aside for just this purpose. As each layer was placed the gaps, voids and between stone spaces were filled with the heart stones.
The heart stones are the smaller and odd shaped stones that are placed/wedged into the middle spaces to fill those spaces and contact with the stones either side. These stones are everywhere and using them in the wall helped to clear the garden.
Building the wall is a bit like a huge “real world” game of tetris with the worst game pieces imaginable. Getting your head around “what fits” and best fit and what stone could “fit here” takes some practice however you get better and quicker with time. I was amazed at how quickly you can pick just the right stone to fit a certain space once you are moving along with the wall.
I found that walking along the top of the wall allowed me to test for firmness and solidity as the work progressed. If the rocks moved under my feet, then the packing, size or placement needed to be revisited and improved.
Probably the hardest part of the wall construction is that the rock has to be sourced – usually from somewhere away from the work area. Many, many rocks were collected from the paddocks where they had been hit by the slasher or lifted by the grader blade on the driveway. Other rocks were collected to allow me to get the slasher into new areas, previously off-limits to the tractor or mower.
These rocks were levered up with the crow bar, then lifted or rolled into the box trailer and driven to the wall, where they were wheel barrowed to the construction site. Using the box trailer to move the stones might seem wasteful, but after tearing my left calf muscle pushing the wheel barrow up a hill I quickly realised that the box trailer made a lot of sense and was good for my health.
The rocks and stones were then lifted onto the wall and placed according to size, shape and design. Good design follows the principle “one stone on two and two stones on one” – this allows stones being placed in the current layer to cover the joints of the stones in the layer below, making a stronger wall.
Where possible, I tried to mix some quartz in with the granite, to provide colour and texture changes. Eventually the stone will grow moss and the colours will be less obvious, but it looks good for now.
When the wall is finished, I go along with any odds and ends stones to try and fill any gaps between rocks. This serves to strengthen the wall, and gets rid of the “gappy” look.
During the wall construction, I was surprised how quickly the small lizards like Jackie Dragons moved in and can often be seen sun bathing on the rocks.
The purpose of this dry stone wall was to retain soil to allow the garden to be made bigger. Normally the rain would wash the soil through the wall and out onto the down hill side. To stop this, the inside face of the wall was lined with “geotextile material”. Soil was then trailered up and barrowed across to fill the space behind the wall.
After many trailer loads of soil, the inside wall area was filled to the same height as the surrounding ground, with the stone wall providing the edge and step down to the lower ground. Whilst we were moving the soil, we mixed in compost and chicken and turkey manure to help with increasing the soil fertility.
To speed things up and to keep pace with the rate of soil trailering, we started to bury our kitchen compost straight into the soil with no time to formally compost. As a result we have had many potato plants grow straight from peelings, and tomatoes straight from seeds in the kitchen waste from making Guacamole.
Two things have made this garden extension work really well this year. The first is the heat that the dry stone wall captures from the morning and midday sun; releasing this heat back into the ground in late afternoon and evening. I think that this raised our average soil temperature, and got the garden growing earlier than normal for this region.
Secondly, the unusually high Christmas rain provided more than enough moisture to allow vigorous growth of the garden.
This project has proven to be a great excuse to get outdoors, get fresh air and sunshine and burn off some of those unwanted calories.
I have been so impressed with the dry stone wall, that I have just completed a second (12m long) also as a retaining wall, to control another sloping area that was ugly and hard to mow. That project is now at the soil trailering and soil leveling stage, and is starting to look good. I have yet to clean up the left over (unused) stones and fence off the top of the wall as the drop is 1200mm at the high end.
And there you have it. Mr D makes it look and sound really easy. They have been hard yakka for him however he thoroughly enjoys it and don’t they look fantastic?