For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
Girder roof structure.
Modern timber roofs are mostly framed with pairs of common rafters or prefabricated wooden trusses fastened together with truss connector plates timber framed and historic buildings may be framed with principal rafters or timber roof trusses roofs are also designated as warm or cold roof depending on how they are designed and built with regard to thermal building insulation and ventilation.
This article series describes and illustrates the different types of support that prevents roof sagging and wall bulging at buildings including definitions of collar ties rafter ties and structural ridge beams.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
Beams are the choice of structural member because of their incredible load bearing capacity against all conditions.
The tables below give maximum spans for rafters and beams.
Roof structure definitions support choices for sloped roofs cantilevered roofs cathedral ceiling roofs.
Girders often have an i beam cross section composed of two load bearing flanges separated by a stabilizing web but may also have a box shape z shape or other forms.
It is the main horizontal support of a structure which supports smaller beams.
A girder truss is designed to support other secondary roof supports.
A truss is a roof or floor support structure built from a connected series of box or triangle shaped elements to distribute load to a building s walls or foundation.
A girder ˈ ɡ ɜːr d ər is a support beam used in construction.
These are often pre fabricated and sent to a construction site.