Smarter Builds Start Below Your Feet
In the push for faster builds, open-plan designs, and cost-efficiency, more and more builders across Victoria are switching from solid timber joists to POSI struts.
If you’re not using POSI struts yet, or you’re still deciding if they’re worth it, this blog will walk you through how they work, where they shine, and why they’ve become a must-have for modern floor and ceiling framing.
What Are POSI Struts?
POSI struts are a type of open-web floor and roof joist, combining timber chords (top and bottom) with metal webbing in the middle.
Unlike traditional solid timber joists, POSI struts create open space within the structure — allowing plumbers, electricians, HVAC installers and sparkies to run services without drilling, notching, or modifying the frame.
Why Builders Love POSI Struts
Easier Service Installation
POSI struts are built with open web spaces, so there’s no need to drill holes for pipes, cables or ducting. This means faster work for tradies and fewer framing issues or delays.
Longer Spans, Fewer Supports
Need to span wide rooms or open-plan living areas? POSI struts can stretch longer distances without the need for mid-span supports or load-bearing walls.
Lightweight and Easy to Handle
Despite their strength, POSI struts are lighter than solid timber alternatives. This makes them easier to carry, position and install on-site — especially helpful in upper floors or tight spaces.
Less Waste, Less Hassle
Because they’re custom-made to your plans, you get exactly what you need — no offcuts, no fixing mistakes, and no extra engineering surprises on site.
Cost-Effective Over the Whole Build
While POSI struts can cost a little more upfront than basic joists, they save serious money on installation, coordination, and call-backs. Less cutting, less hassle, less time = real savings.
Where POSI Struts Are Most Commonly Used
- Upper storeys in double-storey homes
- Townhouses and apartments
- Floor systems above garages or basements
- Ceiling voids where ducts or wiring need space
- Flat or low-slope roof structures
If your design includes a lot of services or open spans, POSI struts will almost always make life easier.
Builders Aren’t the Only Ones Who Benefit
- Plumbers & sparkies can install faster and cleaner
- Engineers love the load-handling and predictable specs
- Clients get better floor performance with fewer squeaks and problems later on
Built to Australian Standards
At US Truss, all our POSI struts are designed using certified engineering software and built in our Dandenong facility using structural-grade timber and galvanised steel webs. They fully comply with AS/NZS 1684 and relevant codes for use in Australian homes.
We Design & Deliver Across Victoria
We manufacture POSI struts to suit your exact spans and load requirements then deliver them to site across Melbourne and regional Victoria. We can even coordinate delivery with your roof trusses, wall frames and flooring sheets to keep your schedule running smoothly.
Ready to Upgrade Your Floor System?
If you’re building smarter and want to streamline your structure from the ground up, POSI struts are the way forward.
Talk to our team at US Truss we’ll give you the advice, materials and service to get your project moving.