A truss is a rigid framework of timber, usually arranged in triangular units. Trusses span between load-bearing walls or columns and are designed o support the roof. The main function of trusses is to transfer the weight from the roof or upper story of the building to the exterior walls without needing any other support from below.
Trusses are an important design component, creating the look and feel of the entire house. There are a number of truss styles to choose from, depending on person preference, load capacity, window placement, and room layout. Truss styles can also be combined to create your home's own unique look. The most common truss choices are shown below
The King Post trust joins a horizontal beam with the roof rafters and support posts. A central kingpost is used to support the ridge joint and stands on the horizontal beam.
King Posts are Ideal from great rooms of areas where the trusses will have to span greater distances. This design is also suitable for the addition of central decorative pendant. However the lower clearance height of this system compared to the hammer beam needs to be considered when choosing this design.
The Queen Post truss utilizes two posts supporting the rafters with a smaller cross beam connecting the posts.
This truss allows carvings to be placed either above or below the center of the space and effectively opens up entryways and focal points in your own home. This design allows for a window or eye-catching architectural element under the ridge, while keeping the lower part of the wall open for picture windows or large furnishings.
The Hammer Beam is probably the most interesting type of truss design and is made of a stacked arrangement of short beams and shaped support braces. These relatively short beams can be used to span fairly large distances, of about 24 feet, without the need for vertical support posts. This gives you the advantage of unobstructed vaulted space. This design is well suited to the addition of timber pendants or other decorative carvings.
Arch-braced trusses come in a variety of forms. Most, though, begin as a simple set of rafters with a collar tie located from the mid-point to the upper third point of the rafter, with the arches extending down to, or near, the rafter feet.