The use of wood may be discussed under the 2 heads of carpentry and joinery: the former consists principally in using large timbers, rough, adzed, or sawn; the latter employs smaller pieces, always sawn, and with the exposed surfaces planed. Carpenters' work is chiefly outdoor, and embraces such objects as building timber bridges and gantries, framing roofs and floors, constructing centreing, and other heavy or rough work. Joiners' work is mostly indoor, and includes laying flooring, making and fixing doors, window sashes, frames, linings, partitions, and internal fittings generally.