The content below was copied with the generous permission of the author Sean Adcock.
This Master Class article originally appeared in issue 33 of Stonechat, produced by the North Wales Branch of the Dry Stone Walling Association of Great Britain. This entire issue of Stonechat, and many more, are available at http://www.dswales.org.uk/Stonechat.html
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Mind the Gap
Having used a fat tony presumably to solve a problem (albeit often self-inflicted) we are likely creating another for later. I have touched upon the problem of building on smaller stone in previous Masterclass articles.
The situation in ‘d’ however could probably benefit from a bit more explanation. The question mark exists because I was looking at this approach primarily from a random walling perspective where b is often the better option especially with smaller ‘filler’ stones, d creates problems as the small stone’s surface does not provide much of a base, so you need two stones that butt very well if they are both going to sit on it. Plus if you repeat this directly above on subsequent courses you might as well have a running joint in all but name, since there is so little effective overlap whatever you do it is a ‘weak’ joint (right). By and large FTs are going to be wider than ‘filler’ stones unless they are slim tonys (or long tall sally’s or soldiers or whatever we decide to call them) and so you are more likely to be able to two stones to sit relatively well. It will still require two stones that butt together closely if they are not going to create poor(er) jointing, but with more regular stone this is less likely to be an issue.
Here the FT (x) is about as wide as it can be without in effect just being another building stone (ie as wide/wider than tall). Stones ‘a’ and ‘b’ sit on it and have good contact with each other but as you can hopefully appreciate there is little room for manoeuvre, the need for careful and precise building on the FT should be obvious.
It can be very tempting to get the 2 stones to have good contact with ‘x’ at the face but have minimal, even just point, contact with each other (as shown right). If, as I believe and preach, one of the keys to good walling is to minimise weaknesses and not to congregate compromises then it is perhaps easy to begin to push the envelope too far here.
The lack of ‘wriggle room’ can become a problem as you are dictating what is needed alongside these stones more than normal. For the sake of argument imagine we are struggling to find a suitable stone ‘c’ and need it to be a cm or two wider to sit well over the joint below it. Often the solution would be to nudge ‘a’ slightly to the left but here it would come off x, so not only does ‘a’ have to sit on x it has to create a suitable environment, so to speak, for ‘c’. Similarly ‘b’ needs to accommodate ’d’. If ‘b’ was much narrower it would another fat tony and we’d be in danger of getting a ‘string’ of them up the wall potentially weakening it (similar to the diagram, previous page).. If ‘b’ was much wider there’d be little chance of ‘d’ sitting on ‘e’, plus it would likely compromise the jointing to its right as well, unless it was a FT too.
This is not all the fault of the original FT, x, as it also depends on the stones alongside it, but it hopefully .illustrates the knock on problems that can occur and how you need to try and think ahead and envisage how the next course will interact with what you’ve just done and hopefully limit/reduce the severity of, subsequent problems. With hindsight here the use of a FT was probably a poor decision give the subsequent apparent problems finding a wider stone to replace both it and ‘e’might have been the wiser choice, dare I even suggest that even tracing this stone (provided it had good contact and reasonable depth into the wall) would have been the lesser of two evils. All this should become fairly obvious .with ‘the benefit of hindsight’, however one of the keys to better walling is to try and hone ‘the benefit of foresight’ and not create and compound such situations in the first place.
Finally to closing the gap, something that is not easy to illustrate, so you’ll just have to make do with a bit of (over) theorising.
In theory when walling we work in a sequence, we place a stone, then one next to it and then one next to that. You would expect this to certainly be the case with coursed walls, more so perhaps than random ones. However it doesn’t always work that way in practice, the less brick like the stone the more it tends to vary. This series started noting “In order to achieve the coursing you have to learn how much variation between stones you can accommodate (or put another way get away with). This approach is something I have written about in “Clawdd Construction” … In practice this often means you select a stone which is close, but doesn’t quite fit where you intended (ie next), perhaps it sits just a little too proud of the line. Because we are coursing and there is some variation of stone size within the course there is a good chance say that 3 feet along the wall theres a slight dip and it fits there perfectly so we put it there. Maybe the next stone is the right height but could cross the joints a little better and it in turn works better a little further along the wall. Hopefully we will get a better wall as a result, with the right stone in the right place. To my mind there is not a lot wrong with this provided we regard those stones as sitting ‘under advisement’. That is they are only provisionally in place. When you reach one it should be rejected if it is creating more problems than it is solving. Such stones should not be seen as ‘set in stone’ so to speak. Hopefully a slight nudge and a good fit means they stay there.
This non sequential approach means that eventually there will be a gap to fill. This is also inevitable if you are working as part of a team, sooner or later you will have a gap to fill when you reach your neighbour’s work. Trying to ‘close the gap’ can be tricky and as with everything else benefits from a little foresight. I would advise trying to tackle the gap with 3 stones. Don’t just wall away and then have a gap for which you are trying to find one specific stone. Working with three stones in mind gives more chance that you are creating that gap for the final stone rather than just finding the final stone to fit a randomly created gap. Having a very good ‘eye’ helps. I seem to be the luckiest waller alive when it comes to finding stones for the final gap. That said I like to think I have created a gap with the benefit of experience, familiarity with the stone (and perhaps a modicum of skill) for which there is a better than average chance the right stone is not far away. At such times I often think of golfer Gary Player. It was once put to him that he was very lucky he replied: “the more I practice, the luckier I get”. Of course having a pact with the devil might help here too. Ultimately, I think the key is probably selecting a final stone that is about the right thickness and about the right width, and workable! A stone that is to short cannot be disjointed, more foresight stretched to fill the hole, a stone that needs a few millimetres shaving off can be made to fit relatively easy. Thickness however can be critical here. It is so tempting to find a stone that closes the gap but sits just proud, or below its neighbours. You are so relieved that if fills the gap that you relax and ignore the problems it will cause when trying to build on it in the next course. More foresight needed, in the long run your walls will get much better when you say no, I created this ‘mess’ and I can do better in solving it than that! In that respect I suspect that we all can always learn and improve. Try and keep the ‘oh, why did I do that’ s to the minimum.
My apologies if this installment is a little short and disjointed.
The end product of the Canadian Project which inspired this mini series. Above photo by Eric Landman.