You can use sbca s span charts to roughly determine truss sizes available.
Parallel chord roof truss span chart.
The truss is a framework consisting of rafters posts and struts which supports your roof.
Basic lumber design values are f 2000 psi f 1100 psi f 2000 psi e 1 800 000 psi duration of load 1 00.
The partial scissor truss is similar except that the bottom chord slopes up in one direction and then straight down while the remaining portion is flat.
Floor truss span tables alpine engineered products 17 these allowable spans are based on nds 91.
Parts of a truss framed roof gable end valley set gi rde t u s dutch hip girder dutch hip framing stepdown hip framing end jack stepdown girder stepdown truss c om n truss 2141 james d hagood halifax va 24558 434 572 1379.
Alpine truss designs are engineered to meet specific span configuration and load conditions.
The bottom chord of the cap truss is typically moved up 1 1 2 for 2x4 continuous lateral restraints over the flat top chord of the base truss or the thickness of whatever material may be used 3 4 for plywood osb etc.
Jbs 11 17 truss types.
Spans shown are in feet 4.
Total load psf duration factor live load psf roof type 55 1 15 40 snow shingle 55 1 15 30 snow tile 47 30 snow 40 20 snow 1 25 20.
Parallel chord trusses allow for greater interior clearance in buildings.
Openings are to be located in the center of the span max opening width is 24 inches 7.
The important point to keep in mind when you use your truss calculator is that every truss calculation is completely unique and is based on the size of your roof and its specific dimensions.
Included are a series of representative roof truss span tables that will give you an idea of the truss spans available for a particular load condition load duration lumber type and truss configuration.
Maximum deflection is limited by l 360 or l 480 under live load.
Tcdl 10 psf and bcdl 5 psf 3.
Spacing of trusses are center to center in inches.
Keep in mind that these tables are for estimations only.
Tcll top chord floor live load 2.
72 5 0 mi ni m u m girder floor truss floor truss jacks a a bearing wall girder floor truss floor truss jacks bearing wall cantilevered floor truss two 2x rim joists 24 max.
The offset scissor truss has a bottom chord that is flat for a distance and then is vaulted up and back down.
And parallel to floor truss span strongback lateral supports 24 max.
Typical flat parallel chord trusses stepdown hip h ip g rde california hip.
Roof floor truss manual 7 31 08 10 43 am page 12.
The shapes and spans shown here represent only a fraction of the millions of designs produced by alpine engineers.
