Raised Tie Roof Truss Dimensions

400mm cellulose insulation to sloped portion of truss.

Raised tie roof truss dimensions.

A rafter tie forms the bottom chord of a simple triangular roof truss. Raised tie roof construction up to 5m span rafter size tie joist h max span max 50 x 175 or 38 x 200 50 x 175 575 5000 38 x 175 38 x 175 450 5000 38 x 150 38 x 150 325 5000 collar rafter. Unlike the conventional truss which is fully triangulated by virtue of its bottom chord fixing the top chords together the raised tie roof completes its triangulation at the flat ceiling to sloping ceiling intersection. This allows access to the existing eaves for the existing roof geometry ensuring no clashes with present roof members.

A raised tie roof truss is a truss where the bottom chord making up the triangle shape moves towards the top of the triangle. As you can imagine the tension is getting up there. Just as there are many types of roofs with many roof parts there are many different types of roof trusses this extensive article explains through a series of custom truss diagrams the different truss configurations you can use for various roofs. 25mm ceiling service cavity batten counter batten roof membrane extra over option.

While this article focuses on configurations we also have a very cool set of illustrations showcasing the different parts anatomy of roof trusses. The raised tie roof truss imposes a horizontal load onto the wall plate and wall when loaded. When ceiling joists run perpendicular to the rafters inspectors may find rafter ties installed above ceiling joists as framing members every 4 feet running above the ceiling joists connecting opposing rafters. 400mm cellulose insulation to flat portion of raised tie truss.

It s imperative on projects of this nature where there are differing wall plate heights and skewed walls that the site dimensions are surveyed and ideally when the walls are somewhere near to wall plate height. As the rafter tie is raised it puts a bending load on the rafter at the point of connection the rafter needs to be deeper as the tie is raised. The run or the base number is 12 inches. The rise will be the elevation change over the 12 inches.

Rafter ties should be at least 2 x 4 inches nominal. Keep in mind that the higher the pitch the steeper the roof. Vcl airtight membrane to achieve 3 0 ac hr. For example a slope of 6 12 means for every 12 inches of horizontal distance the slope of the roof will rise 6 inches vertically.