Roof Joist Vs Truss

Joists joists are supports that run between walls or beams to support the weight of floors roofs and ceilings.

Roof joist vs truss.

Trusses are of many types. The major functional difference between the two is that trusses are built mostly with 2x4s in place of the wider dimensional boards. Trusses are gradually replacing the conventional rafters to the point that nowadays more than 80 percent of new residential construction uses trusses to support the roof. However in canada the most common material used in residential framing is wood so that is the material we will discuss here.

Joists are used in floors and as column support. As trusses are prefabricated they may be costlier than rafters however the installation and labor cost involved in roof rafters is comparatively higher than trusses. While joists support the weight of floors and ceilings trusses have a wide variety of applications including supporting roofs and in bridge design. Floor trusses though are an economical alternative to joists.

This structural support comes in the form of roofing joists ceiling joists rafters or trusses and can be made from a variety of materials including wood metal reinforced concrete etc. The simplest is a planar truss which is used as a roof support system. Both floor trusses and floor joist systems provide suitable structural support. Rafters could take an entire week to be installed whereas trusses could be installed in a day which means trusses could save a lot of time.

Roof framing has undergone a quiet revolution over the past half century. Why has this change occurred and what are the advantages and disadvantages of rafters vs trusses. These triangulated structures with a high degree of strength and stability due to the geometry used form both the joist and rafter components of a building. Because they are manufactured off site according to the specifications of the project the need for alterations is almost completely eliminated.

Trusses and rafters have many common parts including the sloping rafter boards and a bottom joists that form the ceiling of the space below.