Top handrail
The graspable rail and the main structural member resisting the horizontal line load. Often a rounded or oval hollow section with an underside channel that clips over the posts or infill.
Building profiles guide
Aluminium Railing Profiles for Buildings
Aluminium railings are assembled from a small set of extruded profiles: a top handrail, posts, a bottom rail and infill or glass channels, usually in 6063-T5/T6 or 6061-T6 with a powder-coated or anodised finish. This guide explains what each profile does, typical wall thicknesses and weights, the guard height and load rules designers must meet, and how to choose alloy and finish. Metline supplies the railing profiles and stock; installation and the finished railing are the responsibility of the fabricator.
- Alloys
- 6063, 6061, 6005A
- Tempers
- T5, T6
- Wall
- About 1.0 – 3.0 mm
- Finishes
- Powder, anodised, woodgrain
Why aluminium is used for railings
Railings and balustrades on stairs, balconies, terraces, walkways and ramps are a natural fit for aluminium extrusions: they do not rust, need no repainting, weigh about a third as much as steel, and the profile can integrate screw ports, glass channels and cable routes in one section.
A railing system is normally designed by a system company or fabricator and built from repeated standard profiles, which keeps die costs low and makes site assembly quick. Posts are fixed to the slab or stringer with base plates or side fixings; the handrail and bottom rail span between posts; infill of pickets, cables, perforated sheet or glass fills the space between them.
For residential and commercial buildings the main choices are style (picket, glass, cable or panel infill), the post spacing that the profiles can support, and a finish that suits the exposure. Coastal balconies, pool surrounds and public walkways call for a heavier finish class and careful detailing of fixings.
The profiles in a typical railing system
Posts
Square, rectangular or round hollow sections that carry the handrail load down to the fixing. Corner and end posts carry more load and often use thicker walls or internal reinforcement.
Bottom rail
Holds the lower end of pickets or panels and keeps the infill aligned. Lightly loaded, so thinner walls of about 1 mm are common.
Handrail brackets and wall rails
Separate profiles or castings that mount a secondary grab rail to a wall or to posts, as required on stairs.
Glass base shoe and channels
Heavy-wall U-channels that clamp toughened laminated glass along the floor edge, used for frameless glass balustrades.
Pickets and infill
Small square or round tubes, flat bars or perforated sheet panels between rails.
The table shows an example profile set from a typical balcony and stair railing system, with wall thickness and mass per metre. It illustrates how load-bearing members use 2 mm walls while infill-holding rails use about 1 mm.
| Profile | Wall thickness (mm) | Mass (kg/m) |
|---|---|---|
| Top handrail (large) | 2.0 | 2.470 |
| Top handrail (compact) | 2.0 | 2.090 |
| Handrail bracket section | 2.0 | 1.280 |
| Baluster / intermediate post | 2.0 | 1.440 |
| Corner post, 90° | 2.0 | 1.930 |
| Corner post, alternative | 2.0 | 1.987 |
| Bottom rail | 1.0 | 0.320 |
| Bottom rail, alternative | 1.0 | 0.330 |
| Bottom rail cover | 1.0 | 0.280 |
Example values for one system; mass depends on the exact section. Send your drawings for weights of your profiles.
Guard height, openings and design loads
Railings that protect a drop are guards (barriers), and building codes set their minimum height, maximum openings and the loads they must resist. The profiles must be sized so the assembled railing meets these rules with an appropriate safety factor.
| Requirement | International Building Code (US) | Typical European / UK practice |
|---|---|---|
| Guard height, commercial | 1067 mm (42 in) minimum | 1100 mm common for balconies and external edges; check national annex |
| Guard height, dwellings | 914 mm (36 in) under the residential code | 900 – 1100 mm depending on location |
| Handrail height on stairs | 864 – 965 mm (34 – 38 in) | 900 – 1000 mm typical |
| Maximum opening in infill | Must not pass a 102 mm (4 in) sphere | Usually 100 mm sphere |
| Horizontal load on top rail | 0.73 kN/m (50 lb/ft) line load or 0.89 kN (200 lb) point load | Line loads from EN 1991-1-1 national annex or BS 6180, from about 0.36 to 3.0 kN/m by occupancy |
Summary only. Always design to the current code and national annex for the project location; local authorities may impose stricter rules.
Structural design of the aluminium members follows the Aluminum Design Manual in North America or EN 1999-1-1 (Eurocode 9) in Europe. The usual governing checks are post bending at the base, deflection of the handrail between posts, and the strength of the base fixing and anchors into concrete or timber.
Alloys and tempers for railing profiles
| Alloy and temper | Min. yield strength | Where it is used |
|---|---|---|
| 6063-T5 | 110 MPa | Handrails, bottom rails, pickets, decorative profiles |
| 6063-T6 | 170 MPa | Posts and rails in standard residential systems |
| 6061-T6 | 240 MPa | Heavily loaded posts, base plates and brackets |
| 6005A-T6 | Higher than 6063-T6 | Structural posts in European systems |
6063 and 6061 minimums from ASTM B221 for extruded profiles; EN 755-2 values apply to EN orders.
6063 gives the smoothest surface for anodising and complex shapes; 6061 and 6005A are chosen when post spacing or loads push 6063 beyond its limits. A useful rule: if the calculation needs a thicker 6063 post wall than about 3 mm, a 6061-T6 or 6005A-T6 post with a thinner wall is usually lighter and cheaper.
Finishes for indoor, outdoor and coastal railings
- Powder coating: the most common finish, in any RAL colour. Specify AAMA 2604 or Qualicoat class 2 for exterior railings and AAMA 2605 or PVDF for severe coastal exposure.
- Anodising: natural, bronze or black, at least 20 µm thickness for outdoor use. Hard-wearing on handrails because there is no paint film to chip.
- Woodgrain: sublimated wood-effect over powder coat, for warmth to the touch and appearance.
- Brushed or polished: for interior stair rails, protected by clear anodising or lacquer.
In marine environments, the fixings matter as much as the finish. Use stainless-steel fasteners with nylon or EPDM isolating washers, avoid direct contact with copper-bearing timber treatments, and seal cut ends and drilled holes before coating where possible.
Cutting, joining and installation notes
- Cut and machineProfiles are cut to length and punched or drilled for pickets and fixings, ideally before coating so that cut edges are protected.
- JoinMost systems are screwed or clipped together with concealed connectors; welding is possible but reduces 6063-T6 and 6061-T6 strength near the weld and spoils the finish.
- FixBase plates bolted to concrete with approved anchors, or side-fixed to the slab edge; edge distances and anchor capacity must be checked.
- InspectCheck post plumb, handrail alignment and opening sizes; load-test sample sections where the specification requires it.
References and standards
- International Code Council – International Building Code, Section 1015 (Guards) and 1607 (Live loads)
- EN 1991-1-1 – Eurocode 1: Actions on structures, imposed loads on barriers
- BS 6180 – Barriers in and about buildings: code of practice
- EN 1999-1-1 – Eurocode 9: Design of aluminium structures
- The Aluminum Association – Aluminum Design Manual
Aluminium (aluminum) railing profiles: frequently asked questions
Which aluminum alloy is best for railings?
6063-T5 or T6 for handrails, bottom rails and pickets, because it extrudes complex shapes with a smooth finish. Highly loaded posts and brackets often use 6061-T6 or 6005A-T6 for extra strength.
How thick should aluminium railing profiles be?
Load-bearing handrails and posts typically have walls of about 2 – 3 mm, while bottom rails and infill channels are often about 1 mm. The final thickness depends on post spacing, the code line load and the fixing method.
How high must a balcony railing be?
Under the International Building Code a commercial guard must be at least 42 in (1067 mm) high; many European projects use 1100 mm for balconies. Local codes vary, so confirm the rule for your site.
Are aluminium railings suitable near the sea?
Yes, with the right finish and fixings: anodising of 20 µm or more, or AAMA 2605 / PVDF coating, stainless fasteners isolated from the aluminium, and sealed cut ends.
Can you supply railing profiles to our own design?
Yes. Send the profile drawings and we can supply the extrusions in the required alloy, temper and finish, cut to length. Fabrication and installation of the railing remain with your team.
Need profiles for a railing project?
Send your profile drawings, finish and quantities. We will confirm alloy, temper, finish and delivery for your site.
