Interactive I-Joist Span Tables

This application will allow you to select a suitable Dindas I-Joist product based on your Single Span project requirements. As EWP designers, we understand that our customers and builders have their preferences regarding permanent Dead Load Deflection. To help you decide on the best product for your job, we have also included the option to select from a predefined maximum deflection list.

This puts your architect, building designer or engineer in the best position to make performance decisions right at the beginning of your project.

Member Type: Single Span Floor Joist

Dimensional Data:

  • Top of floor joist restraint: Continuous restraint
  • Bottom Edge Restraint: max 600mm

Span Type: Single Span – Span distance is the INTERNAL measurement between structural supports

Basic Loading Data:

  • Flooring + Ceiling 40 kg/m2 OR 65kg/m2
  • Floor Live Load = 1.5kPa/1.8kN OR 2.0kPa/1.8kN
  • Standard AS1720.3 Dynamics for 1.0kN Static Load
  • Min. End Bearing Length = 35mm
  • Min. Intermediate Bearing Length = 45


Class 1 buildings are houses. Typically, they are standalone single dwellings of a domestic or residential nature. They can also be horizontally attached to other Class 1 buildings, such as terrace houses, rowhouses, or townhouses. In these situations, they must be separated by a wall with fire-resisting and sound insulation properties.

The Class 1 classification includes two sub-classifications: Class 1a and Class 1b

Max. Centres are the maximum centres that this joist can be installed at. If a joist’s “Max. Centres” is 600mm, the joist can be used at the lower nominated spacings, i.e., 300mm, 400mm, 480mm, and 600mm centres if it’s Max. Joist Centres are 300mm and can only be used at any joist centres equal to or less than 300mm centres.

Flooring vs Max. Centres
Flooring thickness must be checked before installation to ensure it can span the intended Max. Centre spacings.
* Joists with a Max.Centre spacing of 450mm or less = 19mm min
* Joists with a Max.Centre spacing of 600mm or less = 22mm min

The design assumes that the Min. bearing conditions (35mm) or greater have been included. This can be a solid bottom edge bearing (like a wall) or face fixed metal hanger.

These calculation results will only be used as a handy guide (not for construction) when designing your project joist spans. For final design confirmation and further design options, including continuous spans or non-uniformly loaded joists, please refer to the Dindas Design Guide, contact us at any of our state locations, or request information through