Setting up is one of the most important parts to building a wall efficiently. Setting up for rebuilding an old wall involves stripping out the existing wall, and preparing the foundation. Setting up for a new wall includes preparing a foundation, having stone brought to the site, and organizing the work site.
Rebuilding an old wall
If you are rebuilding an old wall, rebuilding typically happens in sections 10 to 25 feet long. Each section should be completely rebuilt before moving on to the next section. Starting on the first section, setting up begins by clearing any brush or debris from both sides of the wall. Ideally you want reasonably clear ground for about 10-15 feet on both sides of the wall.
Once you have clear space, begin disassembling the wall, this is called stripping out. Take the time to sort the stones as you strip out. This will speed up the rebuilding. Stones should primarily be sorted by thickness, with thicker stones near the wall, and thinner stones farther away. Through stones should be set aside, and cope stones should be set farthest from the wall. Small stones to be used for hearting should be placed in piles near the wall every 6 feet along the wall.
On a freestanding wall, stones should be equally distributed on both sides of the wall, don’t put thick stones to one side and thin stones to the other. Remember to leave a path clear of stones about 18 inches wide right along both sides of the wall. This gives you a place to stand. On retaining walls, typically all the stones should be stripped out to the downhill side. Excavated soil, and sometimes cope stones or hearting, can be placed on the uphill side. The Stone Trust has written detailed engineering specifications for dry stone retaining walls for use by contractors and designers, click here to access these design specs.
Generally speaking all the stones should be removed, right down to bare dirt, when stripping out. Any roots or organic debris in foundation should be removed and dirt should be flattened and firmly compacted. Stomping back and forth several times with your boots is typically sufficient. If the wall is going up a slope, step the foundation so you have level shelves. The foundation should typically be 4-6 inches below ground level on the lower side. Going deeper serves little purpose and uses up more stones. If the footing stones are excessively large, they can be re-positioned one at a time without fully removing them from the wall foundation. Once the stone is sorted and the foundation is prepared, you are ready to set up string lines and begin building.
Building a new wall
Building a new wall begins by preparing a foundation. When building a field wall, remove any topsoil, roots and organic matter from the where the wall will be built, and firmly compact the subsoil. Typically 4-6 inches below ground level is sufficient. Just like for rebuilding, clear space is needed along the wall. There should be sufficient access to have the stone delivered right next to where the wall will be built. If not, you will need to figure out a way to get it there. When stone is delivered in a dump truck it leaves a big pile, sizes are all mixed up, and hearting, if there is any, is at the bottom. It is worth every bit of your time to sort through the pile before you begin building. I find the most efficient method is start on one side of the pile and sort it into rows according to thickness, not overall size. As the pile gets sorted the rows get longer. I set this up so that the rows are parallel to the wall, with the thickest stones closest to the wall.
If you are working from palletized stone, it is still often worth opening all the pallets and sorting through the stone before beginning to build. Some palletized stone is already graded by size in which case further sorting is not needed. However, these pallets are often intended for veneer, and lack the large stones you need for though stones and features. I try to avoid palletized stone whenever possible. It is more expensive, tends to have inadequate size variation, and dealing with the pallets and wire cages takes time. You also need a big piece of equipment to move pallets of stone, which often weigh over 4000 lbs.
Determining how much stone you need for a new wall is always a challenge. When buying stone by the ton, I find I get about 10 cubic feet of wall per ton of stone delivered. Note that is cubic feet, not square foot of wall face, so if your wall is an average of 2 feet thick and 45 inches high, 1 ton of stone will give you 2 feet of length. This translates into about 1.8 tons per cubic yard of wall built. Of course, there is considerable variation due to the density of the stone, and how tightly the stone is stacked in the wall, so this is just a place to start.