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What are common I-Joist applications?

I-joists are most commonly used in residential floor and roof framing applications. They are ideal for cost-efficient long spans, including continuous spans up to 12m over intermediate supports. Because our RFPI range of I-Joists is straight and true, it’s easier for builders and installers to build quality level framing surfaces.
For the full-size range of our joists check out the RFPI Size Guide.


What are Dindas RFPI I-Joist?

Our range of I-Joist are straight, strong and lightweight ‘I’ shaped quality engineered wood structural members that have outstanding performance qualities.
The ‘I’ shape of the joists is formed utilising specially graded LVL horizontal flanges top and bottom which resists bending forces, separated by an engineered
vertical ‘OSB’ – (oriented strand board) web which provides outstanding shear resistance.

Can you show me how to correctly install the RFPI I-Joist?

Sure we can.
Here is the Installation Guide

You should also check out the Technical Resource Page for our range of construction details including 3D models for a more in-depth view of how things should work together.

Do I-Joists have camber or a Top and Bottom?

Great question, as I-Joist, are a ‘balanced’ product (symmetrical LVL grades top and bottom) therefore, there is no actual top or bottom. However, all Dindas RFPI joists have an added advantage with prescored ‘knockout holes’ through the vertical web at 400mm centres located along the labelled flange side of the joists.

TIP: During installation locate all the labelled joist flanges to the ceiling side (down onto the support structure) which will align all the knockout holes. It also increases the joist identification options for your building inspectors/certifiers.


What about Holes through the I-Joist?

Before drilling holes through the Web you should review the Web Hole Guidelines

TIP: It is critically important to note, NO cuts, notches and holes of any kind are permitted in the top and bottom flanges of our I-Joist.

This will immediately void your warranty and require a remedial design at an additional cost

What are my options for I-Joist widths?

The RFPI® range of Dindas I-Joist are available in 4 standard widths:

  • 45mm wide flange with a thickness of 35mm
  • 52mm wide flange with a thickness of 35mm
  • 58mm wide flange with a thickness of 38mm
  • 90mm wide flange with a thickness of 38mm

Further information on the full-size range of our I-Joists check out the details here


How should I fix my particleboard flooring?

There are a few factors to consider with this question,

  1. The AS1860.2 Australian Standard for Particleboard flooring setouts the installation requirements for particleboard flooring non-dependant on the manufacturer, however, it also refers you to the manufacturer’s recommendations.
  2. Solid Timber joists vs I-Joists. There are a clear set of guidelines for fixing size, grade and spacings for particleboard to solid timber fixing BUT, for I-Joists due to the lack of updated testing the standard (and most manufacturers) simply have adopted the following;

Particleboard fixing to I-Joists must be SCREW fixed (not nails) with a Type 17 countersunk, self-drilling wood screw – 10g x 50mm

Whilst we always recommend that screw fixing is the best method for your particleboard flooring, we also understand the installation and perhaps cost constraints these fixings bring. What we have undertaken here at our internal testing R&D structures lab, is to independently test our preferred particleboard product – Structaflor® with a nailing option exclusively for our RFPI I-joists which meets all the code and AU Standards requirements.
Please contact us directly for more information.