The clear distance between supports measured along the beam.
Continuous Span Beams
Continuous span values given in the tables should only be used where:-
a) The beam is not notched or partially cut through at internal support points and,
b) If the spans are not equal, the largest span is not greater that twice the smallest adjacent span.
However if either of the above conditions are not met, use the single span tables for the largest span to obtain the appropriate size.
Overhang Span (sometimes referred to as cantilever)
The distance from the face of the support to the free end of the beam, measured along the beam.
Tables such as those for rafters, floor joists and ceiling joists require the spacing of members to be known or selected so you can obtain the required size for a given span. Spacing should be interpreted as the centre to centre distance between adjacent parallel members.
Roof Load Width
Roof Load Width (RLW) is used in these tables to determine the load applied to isolated roof beams such as strutting beams etc. Roof Load Widths (RLW) are measures of the load applied from roofs. RLW should be determined in accordance with AS1684 Residential Timber Framed Construction.
Ceiling Load Width
Ceiling Load Width (CLW) determines the load applied to single roof beams such as hanging beams, strutting-hanging beams etc. CLW are measures of the load applied from ceilings. CLW should be determined in accordance with AS1684 Residential Timber Framed Construction.
Roof mass has been separated into two categories related to the type of roof cladding — sheet and tile roof only. The roof masses are set forth in AS1720.3:2016 – Timber structures Part 3: Design criteria for timber-framed residential buildings.
Mid-rise timber buildings are typically 4 to 8 storeys high. Have an effective height of not more than 25 metres.
An element not less than 75 mm thick as measured in each direction formed from chemically-bonded laminated timber and includes
- Cross laminated timber (CLT)
- Laminated veneer lumber (LVL)
- Glued laminated timber (Glulam)