Drystone Walling has been around for millennia, and can be found all over the world. Indeed the Cirencester amphitheatre (only the earthworks remain) was constructed with mainly drystone techniques. Fundamentally though, DSW is about the precise placement of stone in such a manner that no mortar is required. The close fit, weight of the stone and shaping (known as batter) all combine to give it strength as well as beauty in its purpose. Did you know 1 SqM of stone weighs about 1 Tonne?
So you don't use cement? No, not in the construction or foundations, though you may sometimes see it used to strengthen gate posts and quite often along the top of a wall. This is called capping and is a cheaper way of finishing a wall off as it uses less stone.
Traditionally walls are finished off by "Topping" with stone; colloquially called Cock and Hen. There are a few variations that you will see in the Cotswolds. Price and security is normally the biggest influencer of the topping style used.
Tell me about batter! This is the deliberate sloping effect built into the wall, normally on both sides of the wall. Essentially the base is wider than the top, and this provides the stability. Typical slope will be about 7-9 degrees, or 1:6. This gives the wall strength and crucially allows the wall to drain water. Each layer of stone, known as a course, is also guided by lines attached to the batter frame. These can be wood or metal poles. The lines keep the courses level and mean the waller can keep to the desired width thus creating the right batter.
Cotswold stone is easy to wall right? Cotswold stone is an Oolitic Jurassic Limestone. It is generally flat, quite uniform and with pronounced edges. Appearance can be anything from light grey to amber yellow. But it doesn't come out the ground in perfect uniform shapes, so it takes skill, time and effort to maintain a steady level course. Because of the flatter nature of the stone compared to Northern granites, Cotswolds walls usually have more courses to make up the wall height. Simply put, it takes longer.
So what holds it together? As already mentioned, the weight alone is significant; however, each stone laid on the wall is pinned in place with smaller stones, and the gap between the two opposing faces is filled with smaller stone also carefully placed so that the wall becomes filled out and sturdy. This infill is known as hearting and is the key to a good wall. Skimp on the hearting and the wall won't last as long as it could. So, it's weight and friction doing the job.
Can you reuse old stone? I will always try to reuse stone that is on site, providing that it has not lost its structural integrity. Some limestone can be prone to splitting and weakening due to the effects of weather, but it's rare to find wholesale failure. Walls usually fail due to other influences - like animals or cars! If the stone is in useable condition there is no reason it cannot be used again on the faces and last for generations. Nothing gets wasted though and if nothing else I will use it for hearting incorporating it back into the wall.
What if I need new stone? Once we have determined exactly what is required I will be happy to arrange collection and delivery of the stone, or you can arrange this yourself. We are blessed with a number of good quarries throughout the cotswolds, so finding a match for your existing stone should be possible, and in time it will weather and blend in.
How long does it take to build a drystone wall? There are a number of factors that can effect the speed at which a wall can be built - not least: the length, height, location (flat or sloping ground, access and proximity to traffic) quality of the stone, and even the weather all play their part in determining how long it will take. But I will be able to give you a good guide after the consultation and of course keep you up to date during the job.