### rafter The rafter framework of a roof is such a roof-structure in which the shell-vault is supported by an A-shaped beam, pairs of wooden bars and spars. These are held by the wall of the building or the vertical beams that laid in the wall. It was not uncommon that each pair of spar is connected to a cross-beam. Rafters were stabilised with roosts in order to prevent them sliding. The roost is also referred to as a collar-beam. To prevent falling sideways, rafters were propped up and joined by roof battens. TI