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.
Roof joist vs truss.
Floor trusses though are an economical alternative to joists.
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.
Joists are used in floors and as column support.
Joists joists are supports that run between walls or beams to support the weight of floors roofs and ceilings.
Because they are manufactured off site according to the specifications of the project the need for alterations is almost completely eliminated.
However in canada the most common material used in residential framing is wood so that is the material we will discuss here.
Trusses and rafters have many common parts including the sloping rafter boards and a bottom joists that form the ceiling of the space below.
It is like the skeleton a building.
The joist also called bandsill supports the load which the floor is built to bear.
Trusses are of many types.
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.
Why has this change occurred and what are the advantages and disadvantages of rafters vs trusses.
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 trusses in many modern construction projects prefabricated roof trusses are used.
The simplest is a planar truss which is used as a roof support system.
The major functional difference between the two is that trusses are built mostly with 2x4s in place of the wider dimensional boards.