Steel is strong, but bare steel rusts. The finish you choose protects the member for the life of the build, so it deserves as much thought as the size. Brisbane’s humidity, summer storms and, closer to the bay, salt in the air all make the choice matter.
Raw steel
Raw or mill-finish steel has no protective coating. It suits members that will be fully enclosed and kept dry, or steel that will be coated after installation. Left exposed, it will start to rust quickly.
Primed and painted steel
A primer coat protects steel during transport and installation and gives paint something to grip. Primed steel is common for internal beams and for steel that will be finished to match the building. It relies on the paint system staying intact, so damaged areas need touching up.
Pre-galvanised steel
Pre-galvanised hollow sections are coated with zinc during manufacture. The coating is lighter than hot-dip galvanising but gives good protection in many sheltered and under-house positions, which is why it is widely used for posts.
Hot-dip galvanised steel
Hot-dip galvanising dips the finished member in molten zinc, coating it inside and out with a thicker layer. It is the usual choice for steel that is exposed to the weather, sits near the ground, or is close to the coast, and it can be specified after fabrication so welds and cut ends are covered too.
How to choose
- Check the drawings first. Your engineer or designer may already specify the coating.
- Think about exposure. Inside and dry, under the house, out in the weather, or near salt air each point to a different finish.
- Plan for fabrication. If a member will be welded or drilled, decide whether it is galvanised before or after that work.
Finishes from Ace Posts and Beams
We supply beams and posts raw, primed or galvanised, and fabricate assemblies in our Eagle Farm workshop to the finish your job needs. See our steel fabrication in Brisbane page, or ask us about the right finish for your job.