What is pre-painted trapezoidal sheet?
Pre-painted trapezoidal sheet is roll-formed from steel that is first hot-dip zinc coated and then painted on a continuous coil-coating line (PPGI). The zinc layer protects the steel against corrosion; the paint adds colour and shields the zinc from the environment. This two-layer protection makes pre-painted sheet a longer-lasting choice than plain galvanized sheet for visible roofs and facades.
Choosing a colour
Colours are specified by RAL code. The most requested shades for trapezoidal sheet are:
- RAL 9002 grey white: industrial buildings and warehouse walls; a light tone that reduces heat gain on roofs.
- RAL 3009 oxide red: close to roof-tile colour; houses, barns and agricultural roofs.
- RAL 7016 anthracite grey: modern facades and residential roofs.
- RAL 6005 moss green and RAL 5010 gentian blue: rural buildings and corporate-colour facades.
Other RAL colours can be supplied on request. Ordering all sheets for a project at once reduces the risk of shade differences between production batches. See pre-painted steel colours and RAL codes.
Paint system
Standard pre-painted trapezoidal sheet uses polyester (PE) paint. For strong sun and UV exposure, coastal or chemically aggressive environments, SMP or PVDF systems keep colour and gloss longer. We compare them in PE, SMP and PVDF paint systems.
Profile, thickness and length
Pre-painted sheet is roll-formed in the same profiles as galvanized trapezoidal sheet. The most common roof and wall profile is 27/200; for industrial roofs with wide purlin spacing the higher-rib 38/151 is preferred. Thickness is usually 0.40–0.50 mm for walls and 0.50–0.70 mm for roofs; the final choice depends on purlin spacing and snow and wind loads. Sheets are cut to the required length in one piece. See trapezoidal sheet sizes for effective widths.
Handling and installation
- Lift sheets rather than dragging them to avoid scratching the paint; remove any protective film right after installation.
- Abrasive cutting discs burn the paint and leave rust spots; use shears or a nibbler.
- Use colour-matched self-drilling screws with EPDM washers. For screw size and quantity see trapezoidal sheet screws and roof pitch.
- In heated buildings condensation can form under a single-skin sheet; where insulation is needed consider a sandwich panel.
What we need for a quote
Price depends on thickness, RAL colour, paint system, profile, sheet length and total quantity; because steel prices change often, current prices are given as a quote. Please send the colour (RAL code), thickness, profile, sheet length and quantity (or roof dimensions) and delivery location. Request a quote for pre-painted trapezoidal sheet.
Applications
- Industrial and warehouse roofs
- Factory and warehouse facades
- Residential roofs
- Barns, greenhouses and agricultural buildings
- Canopies, car parks and garages