VJ or vertical joints (also known as tongue and groove) run vertically to create a wall and were very common in old Queenslanders. Tongue and groove is a method of fitting similar objects together, edge to edge, used mainly with wood paneling. It allows two flat pieces to be joined strongly together to make a single flat surface. Each piece has a slot (the groove) cut all along one edge, and a thin, deep ridge (the tongue) on the opposite edge. The tongue projects a little less than the groove is deep. Two or more pieces thus fit together closely. The joint is not normally glued, as shrinkage would then pull the tongue off. Gaps between boards tended to be sealed with beading. Tongue and groove boards have been rendered obsolete by the introduction of gyrock and other wall sheeting.