Square Base Plate 300mm x 300mm

The all-purpose base plate for square and round posts. Weld it to the bottom of an SHS post, then bolt it down to a slab, footing or deck. With the post centred and a hole in each corner, the load spreads evenly in every direction. That makes it the default choice for pergolas, carports, shade sails, letterbox posts and handrails.

• Laser cut from Australian-made BlueScope structural steel: HA250 to AS/NZS 1594 (3–12mm) and Grade 250 to AS/NZS 3678 (16mm). 250 MPa minimum yield.
• 4 fixing holes, one in each corner, positioned to AS 4100 minimum edge distances for the bolt size.
• Radiused corners for safer handling and better paint and powder coat coverage.
• Laser cut for clean edges and accurate hole positions, so every plate in a batch lines up the same.
• Supplied as raw steel, ready to weld. Paint, prime or powder coat after welding for outdoor use.

For structural work, check the plate size, thickness and fixings against your engineer's or kit manufacturer's specification.

Which post does this plate suit?

Bolt size	Hole	Largest square post
M16	18mm	200mm SHS
M20	22mm	200mm SHS
M24	26mm	150mm SHS

Sizes leave room for the weld and a standard washer and socket at each corner hole. A round post of the same diameter or smaller also fits. For structural columns, use the plate size your engineer specifies.

Need a different size, hole pattern or shape? Contact us or use our online quote. We draw and laser cut custom plates in-house in Gympie.