Extruded hat channel
Made from 6xxx alloys through a die. Walls can vary in thickness, corners can be sharp, and features such as screw ports, serrations or gasket grooves can be built in. Best for structural rails and visible sections.
Omega and top hat sections
Aluminium Hat Channel & Top Hat Sections
An aluminium hat channel, also called a top hat or omega section, has a raised centre and two outward flanges, so it can be fixed to a wall or frame through the flanges while its top face carries cladding, boards or panels at a set distance. Metline supplies extruded and roll-formed hat channels in 6063, 6061, 6005A and 5xxx alloys, in standard sizes or to drawing, to customers worldwide.
- Shape
- Top hat / omega section
- Routes
- Extruded or roll-formed
- Alloys
- 6063, 6061, 6005A, 5052, 3003
- Standards
- ASTM B221 · EN 755 · EN 1999
What is an aluminium hat channel?
The section has five elements: two flanges that sit against the supporting surface, two webs that rise from them, and a crown that forms the top of the "hat". Fasteners go through the flanges into the substrate; panels, boards or skins are fixed to the crown.
Because the material sits away from the neutral axis in both directions, a hat section is far stiffer than a flat strip of the same weight, and stiffer than an angle in most fixing arrangements. It also creates a cavity between the substrate and the finished surface. That cavity is the reason the profile is everywhere in building envelopes: it ventilates rainscreen cladding, levels uneven walls, and leaves room for insulation, cables or acoustic layers.
Aluminium hat channels replace galvanised steel where weight, corrosion and thermal movement matter. Aluminium weighs about one third as much as steel for the same volume, does not rust at cut edges or fixing holes, and moves at the same rate as aluminium cladding panels, which avoids stress and rattling at the fixings.
Extruded and roll-formed hat channels
Roll-formed hat channel
Bent from flat aluminium strip on a roll-forming line, with uniform wall thickness and inside radii. Economical for long runs of thin sections; tooling is quicker to set up than a die for some shapes.
Top hat cladding rail
A vertical rail fixed to wall brackets that carries rainscreen panels. Commonly in 6063-T6 or 6005A-T6 with 2 – 3 mm walls.
Furring hat channel
A shallow section, often around 22 mm (7/8 in) deep, fixed to masonry so plasterboard or panels can be screwed to a flat plane.
Perforated hat channel
Punched with slots or holes for fixings, drainage or weight saving; also used as cable support.
Aircraft hat stringer
Formed from high-strength 2xxx or 7xxx sheet and riveted to the skin of fuselage and wing panels. Supplied to drawing and aerospace specification.
Hat channel sizes
A hat channel is described by overall width across the flanges, height, crown width and wall thickness. The sizes below are common across North American and Commonwealth markets; metric equivalents and custom sections are made to order.
| Overall width | Height | Typical use |
|---|---|---|
| 2.75 in (70 mm) | 0.875 – 1.5 in (22 – 38 mm) | Furring, light cladding battens |
| 3.0 in (76 mm) | 0.875 in (22 mm) | Wall furring, ceiling battens |
| 3.32 in (84 mm) | 1.0 in (25 mm) | Panel support, trailer and truck bodies |
| 3.75 in (95 mm) | 0.5 in (13 mm) | Low-profile spacers |
| 4.0 in (102 mm) | 1.0 – 1.75 in (25 – 44 mm) | Cladding rails, roof battens |
| 5.0 in (127 mm) | 1.0 in (25 mm) | Wider panel joints |
| 5.44 in (138 mm) | 2.0 in (51 mm) | Deep cavities, acoustic linings |
| 8.1 in (206 mm) | 0.75 in (19 mm) | Wide flat supports |
Standard supply
- Wall thickness
- about 1.0 – 2.0 mm roll-formed; 1.5 – 4 mm extruded
- Lengths
- 3 m, 6 m, 93 in, 120 in and 20 ft; cut lengths to order
- Roll-forming range
- flange, height and crown up to about 75 – 90 mm, depending on strip thickness
- Processing
- Punching, slotting, drilling, cutting to length and bending
Steel furring channel is sold by gauge; aluminium sections are specified by actual wall thickness in mm or inches. When converting a steel design, check stiffness, not just thickness.
Alloys for aluminium hat channel
| Alloy and temper | Route | Min. tensile / yield | Best for |
|---|---|---|---|
| 6063-T5 / T6 | Extruded | 152 / 110 MPa (T5); 207 / 172 MPa (T6) | Cladding rails, architectural sections, anodised parts |
| 6005A-T6 | Extruded | 270 / 225 MPa (EN 755-2, ≤ 5 mm) | Stronger facade rails and brackets |
| 6061-T6 | Extruded | 260 / 240 MPa | Structural rails, truck and trailer bodies |
| 5052-H32 | Roll-formed | 215 / 160 MPa (typical 228 / 193) | Marine and corrosive environments, formed sections |
| 3003-H14 | Roll-formed | typical 150 / 145 MPa | Light furring and trim |
| 2024-T3 / 7075-T6 | Formed sheet | aerospace sheet values | Aircraft stringers and repair parts |
For building work the deciding factors are usually stiffness and the fixing pull-out strength, both of which favour extruded 6xxx sections with thicker flanges. For roll-formed sections, 5052 gives the best combination of formability and corrosion resistance; 6061 cannot be roll-formed tightly in the T6 temper.
Design and installation notes
- Structural design: facade rails are designed to EN 1999 (Eurocode 9) or the Aluminum Design Manual, using the cladding weight and the wind load for the site. Brackets and rails come from one engineered system.
- Thermal movement: aluminium expands about 2.3 mm per metre over 100 °C. Use slotted holes and sliding fixings so long rails can move, with one fixed point per rail.
- Fasteners: use stainless steel (A2 or A4) or aluminium fasteners; isolate from galvanised or carbon steel in wet conditions.
- Fire and cavities: in rainscreen systems, cavity barriers and the panel and insulation classification govern fire performance; aluminium rails themselves are non-combustible.
- Ventilation: leave the cavity open at top and bottom so moisture behind cladding can escape.
- Thermal bridging: fit isolator pads under wall brackets to reduce heat loss through the subframe.
Finishes, tolerances and inspection
Hidden subframe rails are normally supplied mill finish, because aluminium forms its own protective oxide. Visible sections are anodised (20 – 25 µm for exterior use) or powder coated, and black finishes are common for rails behind open-joint cladding so the gaps read as shadow.
Quality
- Dimensional tolerances
- EN 755-9 or ANSI H35.2 for extruded sections; roll-formed to drawing
- Straightness and twist
- Checked over the full length; critical for cladding alignment
- Coating
- Film thickness measured on anodised and coated sections; QUALANOD or QUALICOAT on request
- Certification
- Mill test certificate to EN 10204 3.1
Where aluminium hat channel is used
- Rainscreen and ventilated facades: vertical rails carrying ACP, solid aluminium, fibre-cement or terracotta panels
- Wall and ceiling furring: levelling masonry walls and soffits before boarding
- Acoustic linings: supporting acoustic panels and absorbers off walls and ceilings
- Roofing: battens and spacers for metal roofs and solar mounting
- Transport: stiffeners in truck bodies, trailer side walls and rail interiors
- Shopfitting and displays: concealed frames for wall panels and signage
- Aerospace: fuselage and wing stringers and repair sections
How to order aluminium hat channel
- SpecifyWidth, height, crown width and wall thickness (or a drawing), alloy and temper, finish, punching pattern, lengths and quantity.
- QuoteWe confirm the die (existing or new), alloy, temper, finish, packing and delivery terms (EXW, FOB, CIF or DAP) for your destination.
- SampleFor new or appearance-critical sections, a short length or finish sample can be supplied for approval before the production run.
- ProcessSections are extruded or roll-formed, cut to length, punched or drilled as required, and inspected for dimensions and straightness.
- DocumentEach delivery carries a mill test certificate to EN 10204 3.1 with cast analysis and mechanical results; coating thickness reports and third-party inspection on request.
- ShipLengths are film-protected, bundled with spacers and packed in cartons, crates or on pallets for sea, air or road freight to your port or door.
References and standards
- ASTM B221 – Standard Specification for 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
- EN 755-9 – Extruded rod/bar, tube and profiles: profiles, tolerances on dimensions and form
- EN 1999-1-1 (Eurocode 9) – Design of aluminium structures: general structural rules
- The Aluminum Association – Aluminum Design Manual (Specification for Aluminum Structures)
Aluminium (aluminum) hat channel: frequently asked questions
What is the difference between a hat channel and a top hat section?
They are the same shape. "Hat channel" is the common North American term, "top hat section" the British and Commonwealth term, and "omega profile" is often used in Europe.
Should I choose an extruded or roll-formed hat channel?
Choose extrusion for structural rails, thicker or varying walls, sharp corners and built-in features. Choose roll-forming for long runs of thin, uniform-wall sections, especially in 5052 or 3003.
Can aluminium hat channel replace steel furring channel?
Yes, in most cases, and it will not rust. Because aluminium is about one third as stiff as steel, the section or spacing must be checked so deflection stays acceptable.
Which alloy is used for rainscreen cladding rails?
6063-T6 and 6005A-T6 are the most common, with 6061-T6 or 6082-T6 for higher loads. The rail size and bracket spacing come from the system design for the wind load.
Do aluminium hat channels need a finish?
Not when hidden behind cladding; mill finish is normal. Visible rails are anodised or powder coated, often black behind open-joint cladding.
Can you punch hat channel to a pattern?
Yes. Hat channels can be supplied with punched slots or holes, cut to length and bundled per project zone, with mill certificates.
Need hat channel for a facade or fit-out?
Send the section, alloy, finish, lengths and quantity, and we will confirm the best route and a delivered price.
.jpg){kind=link}