SHS Column Frames: The Complete Builder’s Guide to Posts, Connections, Bracing and Baseplates

SHS column frames are the foundation of modern Australian residential and light commercial construction. Verandahs, carports, elevated decks, warehouse mezzanines, sub-floor restumping — all of these depend on SHS steel columns and the connections that hold them together. Understanding how the complete system fits together — posts, baseplates, beam connections, and bracing — is what separates a structure that performs for fifty years from one that needs remediation after the first wet season. 

This is the guide that ties it all together. We cover every stage from column selection through to engineering certification, with clear guidance on the connection hardware needed at each step and how each element connects to the others. 

What is an SHS column frame? 

An SHS column frame is a structural system built from Square Hollow Section (SHS) steel posts, connected by horizontal beams and stabilised by diagonal bracing, with each column anchored to its foundation via a baseplate. SHS refers to steel tubes with equal width and depth — a 100×100 SHS post is 100mm wide, 100mm deep, and has a consistent wall thickness throughout. 

The square profile of SHS gives equal stiffness in both horizontal directions, making it the ideal choice for vertical columns that carry loads arriving from any direction. Unlike Rectangular Hollow Sections (RHS), which are stiffer in one axis than the other, SHS columns work equally well regardless of which direction the beam connects from. 

A complete SHS column frame typically includes: 

• SHS columns — vertical posts carrying compression loads and resisting uplift 

• Baseplates — connecting columns to concrete foundations 

• Beam cleats — connecting horizontal beams to column faces 

• Beams — timber or PFC steel sections spanning between columns 

• Bracing — diagonal rods or angle sections stabilising the frame against lateral forces 

• Top plates — where beams rest on top of columns rather than connecting to the side 

Step 1 — Selecting the right SHS column size 

The first and most important decision is column size. The key variables are the load the column must carry, the column’s unbraced height, the wind classification of the site, and the span between columns. 

Application	Typical SHS size	Notes
Lightweight pergola or shade structure	65×65 or 75×75mm	Low load, short spans
Standard residential verandah	90×90 or 100×100mm	Most common residential spec
Single-bay carport	100×100mm	Standard for 3m–6m bay width
Double-bay or large carport	100×100 or 125×125mm	Depends on span and wind zone
Elevated deck, significant span	125×125 or 150×150mm	Tall columns may need upsizing
Commercial verandah or light industrial	150×150 to 200×200mm	Engineer specification required

These are indicative sizes only. Your structural engineer will specify the exact column size based on calculated loads, column height, and site wind classification per AS 4055. The standard structural grade for SHS columns in Australian construction is C350L0 per AS/NZS 1163 — confirm the grade with your steel supplier before purchasing. 

Step 2 — Setting the baseplates 

Baseplates anchor each column to its concrete foundation and must be set before columns go up. Position, height, and level are all critical — errors here cannot be corrected after columns are erected without significant rework. 

Cast-in anchor bolts are preferred where the slab or pier is being poured fresh. A bolt template positions the anchor bolts at the exact spacing matching the baseplate hole pattern. The concrete is poured around the bolts; once cured, the baseplate slides over them. 

Chemical anchor bolts are used when adding baseplates to existing concrete — standard in restumping and retrofit applications. Holes are drilled, cleaned, and chemical adhesive is injected before the threaded rod is inserted. Maintain a minimum 75mm clearance between the baseplate and finished ground level to prevent corrosion. 

Step 3 — Connecting horizontal beams 

With columns plumb and baseplates set, horizontal beams attach to the column faces using beam cleats. The cleat type depends on what the beam is made of. 

For timber beams: SHS timber beam cleats 

The SHS timber beam cleat slides over the outside face of the SHS column and is fastened at the correct beam height using Tri-Fixx M8 Series 500 Tek screws. The timber beam end is then positioned into the cleat pocket and fastened with additional Tek screws through pre-drilled pilot holes. The full connection is made with a standard drill — no weld, no specialist trade beyond a licensed builder. 

For PFC steel channel beams: SHS PFC beam cleats 

Where the horizontal beam is a Parallel Flange Channel (PFC) steel section, SHS PFC beam cleats are used. These capture the flat web face of the PFC beam and are fastened to the column face with Tek screws. PFC beams are specified when spans are too long for timber, loads exceed timber capacity, or a steel aesthetic is desired. 

Step 4 — Choosing the right cleat configuration at each column 

The configuration of cleat at each column depends on how many beams arrive there and from which directions. Walk your structural drawings and confirm the beam count and direction at every column: 

• Corner column — two beams at 90°: use a corner cleat (left-hand or right-hand depending on orientation) 

• Intermediate inline column — two beams in a straight line: use a 2-way inline cleat 

• T-junction column — three beams, one straight and one at 90°: use a 3-way intermediate cleat 

• End column or single connection — one beam only: use a single-sided cleat 

• Beams resting on top of the column: use an SHS top plate instead of a side cleat 

Getting configurations right before ordering avoids expensive re-orders and delays on site. If a column has beams connecting in two different planes — side cleats at mid-height and a top plate at the head — order both separately. 

Step 5 — Bracing the frame 

A frame of vertical columns and horizontal beams is stable against vertical loads but vulnerable to racking — sideways movement under lateral forces like wind. Diagonal bracing prevents this. 

Rod bracing 

Steel rods run diagonally across a panel of the frame, working in tension to resist lateral load. The rods connect to SHS bracing rod cleats on the column faces, with turnbuckles allowing tensioning once the frame is fully erected. Rod bracing is the most common system for residential verandahs, carports, and sub-floor frames. 

Angle bracing 

Steel angle sections run diagonally across the frame, working in compression. SHS steel angle bracing cleats connect them to the column faces. Angle bracing is more rigid than rod bracing and is specified for higher lateral loads — wind zones N5 and N6, communication towers, and industrial frames with large open panels. 

Welded factory assembly vs on-site SHS cleats 

Factor	Factory-welded assembly	SHS sliding cleats on-site
On-site adjustability	None — fixed at fabrication	Full — slides to any height
Response to design changes	Column back to fabricator	Reposition cleat on site
Welder required on site	Yes (for any site welds)	No — Tek screws only
Lead time	3–6 weeks typical	Order and ship within days
Transport	Complex — protruding brackets	Simple — plain columns
Beam angle flexibility	Fixed at fabrication	Full rotation available
Engineering certification	Project-specific only	Manufacturer cert covers all sizes

For most Australian residential and light commercial builds, the SHS sliding cleat system is faster, cheaper, more flexible, and achieves full engineering compliance without the constraints of factory fabrication. 

Engineering and certification requirements 

In Australia, SHS column frames supporting structures that require a building permit must be designed and certified by a registered structural engineer. The engineering documentation will typically cover: 

• Column size, grade (C350L0 per AS/NZS 1163), and wall thickness specification 

• Baseplate type, size, and anchor bolt specification including minimum embedment depth 

• Beam cleat type, configuration, and Tek fastening pattern at each connection 

• Whether Tek-only or Tek-plus-weld connections are required based on calculated shear loads 

• Bracing system specification, panel locations, and rod or angle sizes 

• Site wind classification per AS 4055 (residential) or AS/NZS 1170.2 (commercial) 

SHS Cleats provides engineering certification documentation for all products — beam cleats, baseplates, top plates, and bracing cleats — covering allowable shear and uplift loads across all SHS column sizes. This documentation supports your building permit application and gives your building certifier the compliance evidence needed to approve the structure. 

Frequently Asked Questions 

Building with SHS columns? SHS Cleats supplies the complete connection system — timber beam cleats, PFC beam cleats, baseplates, top plates, and bracing cleats — for every SHS column size from 65×65 to 200×200mm. All products are hot-dip galvanised, engineering certified, and available for same-week dispatch. View the complete SHS cleat range at shscleats.com.au →