GLOSSARY OF TERMS
Waler: Horizontal timber used to hold close sheeting in position.
Lagging: Lengths of sawn hardwood timber planks used to support the sides, walls or roof as necessary of shafts and drives and to prevent material from those faces falling into the excavation. The term is also sometimes used when referring to the layer of poling boards doing the same duty in trenches. The lagging is supported in turn by walkings, legs, caps, sets or frames, as applicable. (See also "lathes" below).
Lathes: Short lengths of hardwood timber usually split and about 1.25 to 1.5 metres long used to support the side walls (and roof in drives) and supported in turn by walings, legs or caps as applicable.
Strut: Hardwood timber (usually horizontal) in compression resisting thrust or pressure from the face or faces of an excavation.
Soldier: Vertical upright hardwood timber used for supporting a trench wall, taking the thrust from horizontal walers and supported by struts.