Surface mount
A post welded or bolted to a base plate sits on top of the deck or slab. Quick to install on concrete; on timber decks the blocking under the plate, not the aluminium, is often the weak link.
Guards and balustrades
Aluminium Picket Railing Systems & Component Kits
An aluminium picket railing is a guard made of extruded posts, a top rail, a bottom rail and closely spaced vertical pickets, used along balconies, decks, terraces and stairs. Extruded from 6063 or 6005A alloy and powder coated, it meets guard height and opening rules without rusting or needing repainting. Metline supplies the posts, rails, pickets and fittings to railing fabricators, installers and projects worldwide.
- Alloys
- 6063-T5/T6, 6005A-T6
- Heights
- 36 in, 42 in, 900 – 1100 mm
- Mounting
- Surface, fascia, wall, core
- Finish
- Powder coat, anodised, wood-grain
What is an aluminium picket railing?
A picket railing (often called a baluster or spindle railing) is the most common guard style for residential and light commercial edges. Vertical pickets sit between a top and a bottom rail, and the assembled sections are fixed to posts that carry the loads into the deck, slab or wall.
The picket format is popular for a practical reason: building codes limit the size of any opening in a guard, and evenly spaced vertical bars make that limit easy to meet and easy to inspect. Vertical pickets also give children no foothold, which is why many codes and guidance documents prefer them to horizontal rails in homes.
Aluminium suits the job because every part can be extruded to shape: hollow posts with internal screw ports, top rails with a channel that hides the picket ends, and bottom rails with drainage. The parts are light to carry onto balconies and stairs, and an architectural powder coat keeps the colour for many years with only occasional washing.
Typical picket railing specifications
The table shows the configurations most often ordered. Every value can be adjusted to a project drawing, but final heights, spacings and post layouts must be confirmed against the local building code and the structural engineer's design.
Standard configuration
- Material
- 6063-T5 pickets and rails; 6063-T6 or 6005A-T6 posts
- Railing height
- 36 in (914 mm) or 42 in (1067 mm) for North America; 900, 1000 or 1100 mm elsewhere
- Section length
- 5 ft, 6 ft or 8 ft (about 1.5, 1.8 and 2.4 m) between posts, or to drawing
- Post size
- 50 × 50 mm (2 in) and 60 × 60 mm common; 63 – 76 mm for commercial guards
- Post types
- End, line, corner, stair and fascia-mount posts
- Picket section
- Square 16 – 25 mm (5/8 – 1 in), rectangular, round or custom profile
- Clear gap between pickets
- Under 100 mm (4 in) to pass the sphere test; typically 90 – 98 mm
- System type
- Modular mechanically fastened, welded panel, or loose component kit
- Mounting
- Surface (top) mount, fascia (side) mount, wall mount, or core-drilled / embedded
- Finish
- Powder coat, anodising or wood-grain transfer
- Colours
- Black, white, grey, bronze, or any RAL colour
| Component | Usual alloy / temper | Typical section | Why |
|---|---|---|---|
| Pickets | 6063-T5 | 19 × 19 × 1.2 mm square tube | Smooth surface for coating; loads are small |
| Top rail | 6063-T5 or T6 | 40 – 60 mm wide channel or shaped cap | Must carry the top-rail load between posts |
| Bottom rail | 6063-T5 | 30 – 45 mm channel | Locates pickets and keeps the bottom gap |
| Line and end posts | 6063-T6 or 6005A-T6 | 50 – 60 mm square, 2.5 – 3 mm wall | Highest bending moment of any part |
| Base plates | 6061-T6 or 6082-T6 plate | 100 – 125 mm square, 8 – 12 mm thick | Strength at the anchors |
Height, opening and load rules for picket guards
A railing on a raised edge is a life-safety component, so most of its geometry is set by the building code of the project location. These are the figures buyers ask about most often; amendments are common, so check the edition adopted locally.
| Rule | US (IRC / IBC) | UK (Approved Document K) | Australia (NCC) |
|---|---|---|---|
| Guard required | Where the walking surface is more than 30 in above grade | Where there is a drop of more than about 600 mm in dwellings | Where a fall of 1 m or more is possible |
| Minimum height | 36 in in dwellings (IRC); 42 in in other buildings (IBC) | 900 mm on stairs; 1100 mm at balconies and landings | 1000 mm; 865 mm along stair flights |
| Maximum opening | 4 in sphere may not pass; 4-3/8 in on stair sides | 100 mm sphere in dwellings and areas used by children | 125 mm sphere |
| Triangle at stair tread / riser | 6 in sphere | Covered by the 100 mm rule | Covered by the 125 mm rule |
| Top-rail load | 200 lb concentrated in any direction; 50 lb/ft line load in IBC occupancies | BS EN 1991-1-1 UK annex and BS 6180 line loads by use | AS/NZS 1170.1 by occupancy |
Because picket spacing is measured as a clear gap, the centre-to-centre spacing depends on the picket size. With a 19 mm picket and a 95 mm clear gap, pickets sit at 114 mm centres, or about nine pickets per metre of rail. Fabricators usually punch rails a little tighter than the limit so that site tolerance never pushes a gap over it.
The gap under the bottom rail counts as an opening too. Set the bottom rail so the space to the deck is below the code limit, or the railing will fail inspection even if the pickets are correct.
Post mounting options and what governs them
Fascia mount
Brackets fix the post to the face of the slab edge or rim joist. Frees the walking surface and gives a clean balcony edge, but the edge must be strong enough to take the bolt loads.
Core-drilled / embedded
The post is grouted into a hole drilled in concrete. Very stiff and tidy; use non-shrink grout and isolate the aluminium from wet cement.
Wall mount
Rail ends fix to a wall with brackets or flanges, removing an end post where the railing meets the building.
Stair posts
Raked sections follow the stair pitch, typically 30 – 37 degrees, with swivel brackets that adjust to the actual angle on site.
Corner posts
Take rails from two directions; corners stiffen a run, so line posts between corners can sometimes be lighter.
Railing posts almost always fail by bending at the base. A 200 lb (0.89 kN) load on a 42 in (1067 mm) post creates a base moment of about 0.95 kN·m before any safety factor. A 50 × 50 × 3 mm 6063-T6 tube has a section modulus of roughly 8,300 mm³, so the stress is about 114 MPa against a specified minimum yield of 170 MPa. That margin explains why 50 – 60 mm posts are standard for homes, and why taller commercial guards move to 6005A-T6, thicker walls or internal reinforcement.
Finishes and colours
| Finish | Typical specification | Best for |
|---|---|---|
| Polyester powder coat | AAMA 2603 / 2604 or Qualicoat Class 1, 60 – 80 µm | Most residential railings |
| Super-durable powder | AAMA 2604 or Qualicoat Class 2 | Strong sun, coastal sites, dark colours |
| Fluoropolymer (AAMA 2605) | Highest gloss and colour retention | Commercial and high-rise balconies |
| Anodising | EN ISO 7599 class 20 – 25 µm; AAMA 611 Class I | Metallic finish, hard-wearing handrails |
| Wood-grain transfer | Sublimated film over powder base coat | Timber look on decks without timber upkeep |
Black textured powder is the most requested colour for picket railings, followed by white, bronze and grey. Textured finishes hide small scratches and fingerprints better than gloss. For balconies within a few hundred metres of the sea, ask for a pre-treatment approved for seaside use and plan a fresh-water rinse a few times a year.
Where picket railings are used
- Balconies and multifamily housing: 1100 mm or 42 in guards on fascia brackets, matched in colour to the window frames, with profiles often cut and numbered per floor.
- Stairs and landings: raked picket sections with swivel brackets, plus a separate graspable handrail where the code requires one.
- Decks, terraces and walkways: 36 in modular kits on surface-mount posts for timber or composite decks.
- Commercial and public buildings: heavier posts and rails for schools, hotels, mezzanines and podium decks, where line loads are higher.
- Pool surrounds: picket railing styles extend into pool fencing with self-closing gates, though pool barriers follow their own height rules.
On a typical balcony project, the architect fixes the height and colour, the engineer sizes posts and fixings for the occupancy load, and the supplier converts the elevations into a cutting list. Profiles are then labelled by unit and floor so installers do not have to sort parts on site.
Picket railing compared with glass and cable infill
| Factor | Aluminium pickets | Glass infill | Stainless cable |
|---|---|---|---|
| View through | Good | Best | Very good |
| Opening-rule compliance | Simple, by spacing | No openings | Needs tight cable tension and close spacing |
| Climbability | Low (vertical bars) | None | High (horizontal cables), restricted in some codes |
| Weight | Light | Heavy | Light, but end posts carry high tension |
| Maintenance | Occasional washing | Frequent glass cleaning | Periodic re-tensioning |
| Relative cost | Lowest | Highest | Medium |
For most homes and apartment blocks, pickets give the best balance of cost, compliance and durability. Glass is chosen where the view justifies the cost, and many projects combine both: glass on the view side, pickets on stairs and side returns.
How to order picket railing profiles
- Share drawingsPlans and elevations, railing heights, run lengths, stair pitches, mounting method and the code that applies.
- Confirm the profile setWe propose post, rail and picket sections and a picket spacing that keeps every gap under the limit.
- Choose finishColour (RAL or wood-grain), coating standard and any matching gate or handrail.
- InspectDimensional checks, coating thickness and adhesion tests; mill certificates to EN 10204 3.1 for the extrusions.
- Pack and shipProfiles and parts labelled per elevation, protected with film or sleeves and packed in export cases on EXW, FOB, CIF or DAP terms.
Profiles can be supplied in standard modular lengths, cut to project drawings, or packed by part number with spare parts for distributors that sell their own railing kits.
References and standards
- International Code Council – International Residential Code R312 and International Building Code 1015 (Guards)
- UK Government – Approved Document K: Protection from falling, collision and impact
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- EN 755-2 – Aluminium and aluminium alloys: extruded rod/bar, tube and profiles, mechanical properties
- BS 6180 – Barriers in and about buildings: code of practice
- FGIA / AAMA 2604 – High-performance organic coatings on aluminium extrusions and panels
Aluminium (aluminum) picket railing: FAQ
How far apart should railing pickets be?
Close enough that a 4 in (100 mm) sphere cannot pass between them in the US and UK, or a 125 mm sphere in Australia. In practice that means a clear gap of about 90 – 98 mm. With 19 mm pickets this works out to roughly 114 mm centres.
What height should an aluminium picket railing be?
In the US, 36 in for homes under the IRC and 42 in for other buildings under the IBC. In the UK, 900 mm on stairs and 1100 mm at balconies; in Australia, 1000 mm. Always check the local code edition.
Which alloy is used for aluminium railing posts?
6063-T6 is standard for residential posts. For tall or heavily loaded commercial guards, 6005A-T6 or 6061-T6 gives a higher minimum yield strength in the same section. Pickets and rails are normally 6063-T5 for the best coated finish.
Can picket railings be used on stairs?
Yes. Stair sections are raked to the stair pitch with swivel brackets. Codes usually allow a slightly larger opening on stair sides and a 6 in triangle at the tread and riser, and a separate graspable handrail may be required.
Are aluminium railings welded or bolted together?
Both exist. Modular systems are mechanically fastened, ship flat and install without site welding. Welded panels are stiffer and have no visible fixings but are bulkier to ship and harder to adjust on site.
Will aluminium railings corrode near the sea?
Aluminium does not rust, and a coastal-grade powder coat over a suitable pre-treatment performs well. Use stainless steel fixings with isolation washers and rinse salt off a few times a year to keep the finish in good condition.
Planning a picket railing project?
Send heights, run lengths, mounting details, colour and destination. We will reply with a component list and a delivered price.
