Pressure Treated Roofing Battens made from steel strip serve as the supporting framework for tiles on sloped roofs. They are shaped by cold roll forming and are intended to replace timber battens, which can rot, attract insects, or lose strength over time. SENBO keeps incoming inspection records for strip thickness and coating mass, and the roll forming lines are checked regularly for profile accuracy. The battens are cut to the required length before delivery.
The main raw material is Al-Zn alloy coated steel strip in grade G550 with AZ150 coating. The coating contains about 55% aluminium and 43.5% zinc by weight, which gives better protection against corrosion than ordinary galvanized strip. The steel must show a tensile strength of at least 370 MPa, a yield strength of at least 265 MPa, and an elongation after fracture of at least 26%. Salt spray testing follows GB/T 10125-2012, while tensile testing follows GB/T 228.1-2010. A minimum nominal thickness of 0.8 mm applies to metal tile battens in pitched roof work.
Standard pieces are 3 m to 4 m long, but longer lengths can be supplied on request. Pressure Treated Roofing Batten spacing follows the effective cover of the tile and usually falls between 300 mm and 370 mm. The applied coating is at least 85 μm thick. Coloured finishes in polyester or PVDF can be added if the design requires a specific appearance.
| Property | Value | Basis or Comment |
|---|---|---|
| Steel grade and coating | G550, AZ150 (Al-Zn) | Also galvanized strip available |
| Tensile strength | 370 MPa minimum | From material certificate |
| Yield strength | 265 MPa minimum | From material certificate |
| Elongation after fracture | 26% minimum | From material certificate |
| Coating thickness | 85 μm minimum | Applied finish |
| Minimum base thickness | 0.8 mm | Pitched roof requirement |
| Common profiles | Angle, flat, omega, hat channel | Chosen by tile type and load |
| Standard length | 3–4 m | Longer lengths possible |
| Typical spacing | 300–370 mm | Based on tile cover |
| Test standards | GB/T 10125-2012, GB/T 228.1-2010 | Corrosion and tensile tests |
The batten system was load tested on a project with roof pitches between 45° and 60°. At the Minquan County Senior High School new campus, L30×4 mm galvanized angle battens were set at 340 mm centres beneath 300×400 mm sintered tiles. Wind forces pass through the tiles into the battens by copper wire ties and mortar, then into the main frame via counter-battens welded to embedded plates. Pull-out tests confirmed the assembly met the design wind load. Battens made from G550 Al-Zn coated steel are also used on large roofs such as airport terminals and stadiums, where long-term stiffness and coating durability are required.
Salt spray testing on AZ150 coated battens shows a marked improvement over ordinary galvanized strip. The combination of aluminium and zinc in the coating provides sacrificial protection and slows rust creep at cut edges. The minimum 85 μm organic finish adds a further barrier in humid roof spaces.
Timber battens in warm, damp climates can be damaged by termites and fungal decay. Steel battens do not support insect activity and do not absorb moisture. This property makes them suitable for southern coastal regions and areas with high termite pressure. Records from large public buildings show Al-Zn steel battens remaining in service for more than 30 years without replacement.
At the Minquan project, the total floor area reached 255,000 m² and the roof pitch ranged from 45° to 60°. The construction sequence started with counter-batten levelling, followed by batten fixing, then tile setting with double-strand copper wire ties and polymer mortar bonding. This approach stopped tiles from sliding on the steep surface and kept the roof watertight. The same sequence can be adapted to other steep pitch buildings.
Treated timber can last many years, but its performance depends on preservative retention and exposure. Steel battens with AZ150 coating do not rot or split and are not affected by termites. In coastal or high-humidity locations, steel is often the more predictable choice.
The tile manufacturer's installation guide normally states the required batten section and spacing. Angle and flat sections are common under heavy clay or concrete tiles. Omega and hat profiles are lighter and often used with metal or composite tiles. Confirm compatibility before ordering.
PV tiles have specific mounting and load requirements. The batten profile and spacing must be checked against the PV tile manufacturer's instructions. Additional fixings or reinforced battens may be needed to carry the extra weight and wind load.
AZ150 is usually the minimum for marine exposure. In very aggressive salt-laden air, a heavier coating or stainless steel may be required. The atmospheric corrosivity category should be determined first, then matched to the available coating options.
Before production starts, the steel strip mill certificate is reviewed for grade, coating mass, and mechanical properties. Dimensional checks during forming cover thickness, profile depth, and straightness. For larger contracts, samples can be sent for independent salt spray or tensile testing. Delivery inspection should confirm length, profile, and absence of coating damage.
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