Blonde Girl Undresses Her Black Panties On The Timber Roof Truss Framework With An Open Ceiling Area

Timber roof trusses were a medieval development. Earlier roofs had been supported by coupled rafters – pairs of rafters linked by horizontal beams. But such roofs were structurally weak, and lacking any longitudinal support were prone to racking, a collapse resulting from horizontal movement.
History
The top members of a truss are known generically as the top chord, bottom members as the bottom chord, and the interior members as webs. In historic carpentry the top chords are often called rafters, and the bottom chord is an often a tie beam. There are two main types of timber roof trusses: closed, in which the bottom chord is horizontal and at the foot of the truss, and open, in which the bottom chords are raised to provide more open space, also known as raised bottom chord trusses.