Tie Beam Roof Truss

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 often referred to as a tie beam there are two main types of timber roof trusses.

Tie beam roof truss. The king post roof truss is the simplest of the trusses because of its simple composition. There is a hierarchy of timber framing at work here with trusses supporting the ridge and purlin beams. A raised tie roof truss is a truss where the bottom chord making up the triangle shape moves towards the top of the triangle. The rafters tie beams and plates serve to transmit the weight of the roof to the walls of the building construction of a truss roof.

Above these components is a rack of common rafters. A timber frame truss roof with ridge beam purlins and common rafters is a stunning combination that creates visual interest and structural complexity. Collar ties rafter ties tension beams structural ridge beams. Some of these can support the roof and prevent ridge sagging and wall spreading.

Tie beam definition a horizontal timber or the like for connecting two structural members to keep them from spreading apart as a beam connecting the feet of two principal rafters in a roof truss. The vertical king post is used to prevent the sagging of tie beam at the centre of a span. Closed in which the bottom chord is horizontal and at the foot of the truss and open in. Unlike other trusses which support on the ceiling tie the bottom chord raised tie trusses are supported partway up the lower end of the rafters.

It is often used in simple roof trusses such as in the shed porch and garage. In king post truss the bottom chord of the truss acts as tie beam and this tie beam receives the ends of the principal rafters and prevents the wall from spreading out due to thrust. The gap in the sheathing at the ridge is the space designed to allow natural ventilation.