Timber Roof Truss Span Tables

View joist rafter tables.

Timber roof truss span tables.

Adding purlins between heavy timber trusses is an elegant way to reduce the cost of a timber frame roof because purlins permit an increased on center distance between trusses so you purchase fewer trusses. Roof truss span tables alpine engineered products 15 top chord 2x4 2x6 2x6 2x4 2x6 2x6 2x4 2x6 2x6 2x4 2x6 2x6 bottom chord 2x4 2x4 2x6 2x4 2x4 2x6 2x4 2x4 2x6 2x4 2x4 2x6 2 12 24 24 33 27 27 37 31 31 43 33 33 46 2 5 12 29 29 39 33 33 45 37 38 52 39 40 55 3 12 34 34 46 37 39 53 40 44 60 43 46 64 3 5 12 39 39 53 41 44 61 44 50 65 47 52 70. Trusses must be designed for any special loading such as concentrated loads. Top chord dead load 10 psf.

View allowable load tables. An added benefit are the strong lines that purlins create by running parallel to the ridge beam s. For simple construction such as domestic construction this can be determined from span table supplements in as1684 2 and as1684 3. View size selection tables.

Construction details should be in accordance with as1684 2. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. Spacing of trusses are center to center in inches. Simplified span tables for southern pine lumber and glued laminated timber glulam headers beams and girders.

Bottom chord dead load 5 psf. Spacing should be interpreted as the centre to centre distance between adjacent parallel members. Technical diagram span tables f7 rafters on page 35 30mm m aximum allow able sp ans mm sheet roof spacing mm rafter size 600 760 900 1000 1200 66 x 30 1250 1150 1050 1000 950 90 x 30 1650. Other more complex load condition spans can be determined with our free hyne timber design 7 5 software.

Roof load width rlw and floor load width flw can be determined from as1684 or from the images below. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Span tables allow users to choose an appropriate size and stress grade to achieve spanning needs. Center line chase 24 max.

Required size for a given span.