Corners
Corners frequently collapse through poor construction or lack of suitable stone. When dismantling a corner, sort the stone carefully, and try and gain some additional long stones by using throughs from just along the wall. As with heads, the result is likely to be stronger if you sacrifice a few throughs and use them to strengthen the corner. Take care when dismantling the inside corner as space is limited, and you will need to spread the stone out further than normal to give you space to work.
Batter frames or line bars should be set up 2-3′ (600-900mm) beyond the ends of the two sections of wall, so they don’t interfere with placing the stones.
The method of construction is similar to ‘L shaped’ heads with each layer overlapping the other below, crossing all the joints. Use large stones with two good outside faces if possible.
As the drawing shows, the face of one section of wall forms the head of the other, and vice-versa. Pack the centre with fillings at each layer in the usual way, and check that each stone in each layer binds well with the stones that touch it. Where the corner stones are 30″ (750mm) or more, it is advisable to also secure them with throughs as they are effectively traced stones.
It is important that the inside of the corner should be built following the same principles, ensuring that there is good overlapping within the wall. Just because the extent of the overlapping cannot be seen from the outside is no reason to skimp on it.
Wherever possible the inside runners should butt up against the inside edges of the face stones on the other side of the wall as shown above left. In addition, where there is suitable stone, try to fit some stones in the inside corner which are effectively long through stones, as shown above right.
Finally, do not build a corner as a junction with two wall heads. As the wall settles, the seam is almost certain to widen, especially if the ground slopes in any direction.
T-junctions
Where two walls meet at a T-junction, you sometimes find that one wall has been simply butted up against the other with a head, or worse, just built up against it with few, if any, tie stones. Either method creates a serious weakness.
A T-junction should be built as effectively two inside corners, following the principles outlined above. It is best to alternate the L shapes as shown. This makes it easier to overlap, especially where longer stones are available to butt up against each other in the higher part of the wall.
Where available, complete throughs or tie-stones should also be incorporated in the junction, either to tie the joining wall into the other, or to tie across the join.
Four way junctions are rare, but the method of construction is as above, trying to apply the principles for T-junctions wherever possible.
