SteelBase Plates
Column and post base plates — profile-cut, drilled and welded to your drawings, ready to bolt down.
A steel base plate is the flat plate welded to the foot of a column or post that spreads its load into the concrete footing and takes the hold-down bolts. Base plates are on almost every steel frame, from warehouse portal frames and mezzanines to carport posts, pipe racks and plant structures. We make base plates from AS/NZS 3678 Grade 250 or 350 plate, 10 to 50 mm thick. They are profile-cut to size, drilled or slotted for hold-down bolts, and supplied loose or welded to the column. Finishes are black, primed or hot-dip galvanised. Every base plate is made to your drawings or your engineer's details, in project quantities, with mill test certificates and fabrication to AS/NZS 5131.
Product Range
Cut to Size
Plasma, oxy or laser cut from structural plate to any size and shape, including chamfered corners and cut-outs.
Drilled & Slotted
Hold-down bolt holes drilled or slotted to suit M16 to M36 anchors, plus grout and vent holes where detailed.
Welded to Columns & Posts
Base plates welded to UC, UB, SHS, RHS or CHS columns to AS/NZS 1554, delivered ready to stand.
Cap Plates, Cleats & Stiffeners
Matching cap plates, cleats, gussets and stiffeners made in the same run so the whole connection arrives together.
Galvanised or Primed
Supplied black, shop primed or hot-dip galvanised to AS/NZS 4680 for exposed and coastal sites.
Steel Base Plate Specifications
Typical column base plate specifications. Every base plate is made to your drawings or engineer's details.
| Item | Typical range |
|---|---|
| Plate thickness | 10 – 50 mm |
| Plate grade | Grade 250 or 350 to AS/NZS 3678 |
| Plate size | 150 × 150 to 600 × 600 mm, or any size to drawing |
| Hold-down bolt holes | 18, 22, 26, 33 mm for M16, M20, M24, M30 bolts |
| Grout and vent holes | Drilled or profile-cut to detail |
| Finish | Black, shop primed or hot-dip galvanised |
Additional sizes, grades, lengths and finishes available on request — contact us for a full size chart and quote.
Common Applications
- Portal frame and warehouse columns
- Mezzanine and platform posts
- Carport, patio and canopy posts
- Pipe racks and plant structures
- Signage and lighting poles
- Equipment and machinery mounts
Relevant Standards
- AS/NZS 3678 — Structural steel (hot-rolled plates)
- AS 4100 — Steel structures
- AS/NZS 5131 — Structural steelwork fabrication and erection
- AS/NZS 1554 — Structural steel welding
- AS/NZS 4680 — Hot-dip galvanized (zinc) coatings on fabricated ferrous articles
Steel Base Plates — Frequently Asked Questions
What thickness should a steel base plate be?
It depends on the column load, the plate size and the bolt layout, so your engineer sets it. Light posts often use 10 to 16 mm plate; portal frame and mezzanine columns typically use 16 to 32 mm; heavy plant columns can need 40 mm or more.
Can you weld the base plates to the columns?
Yes. We supply base plates loose or welded to UC, UB, SHS, RHS and CHS columns to AS/NZS 1554, with cap plates and cleats, so the columns arrive ready to stand.
What hole size do hold-down bolts need?
Standard holes are the bolt diameter plus 2 mm up to M24 and plus 3 mm above, so 18 mm for M16, 22 mm for M20, 26 mm for M24 and 33 mm for M30. Oversize or slotted holes are used where the detail allows for tolerance.
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