Roof sandwich panel installation: the sequence from preparation to inspection

Compare the design with the order: model, lengths, installation direction and cutbacks. Prepare a panel layout and agree unloading and lifting onto the roof. Do not lift long elements without verifying equipment capacity and accessories.

Check structural alignment and verticality, corrosion protection and connections. Verify support spacing and bearing widths. Load tables apply only to the correct panel configuration and structural arrangement. Do not remove a purlin because the sheet reaches from eaves to ridge: production length is not allowable span.

One manufacturer’s roof-system instructions require a pitch greater than 5% for continuous panels without rooflights, increasing to greater than 7% where end laps or rooflights are present. These are requirements for a particular system, not universal limits. They are percentages, not degrees. Confirm the requirements of the panel actually being purchased.

For example, 5% means a 5 cm height difference over 1 m of horizontal projection. “Greater than 5%” does not mean exactly 5%. Account for actual geometry and structural deflection: local ponding may occur even when the drawing states an acceptable angle. Checking supports before installation helps identify that risk.

Prepare supports and required tapes, and remove protective film as instructed. Position the first panel precisely relative to the eaves and roof axis. Any initial alignment error will accumulate with subsequent elements.

A vacuum lifter may be suitable for placing panels, provided it matches their weight, coating and working conditions. Not every suction device is appropriate. Avoid sliding metal facings over one another. Check the next panel’s joint without damaging edges, and follow the system and roof layout for lap direction.

Select fasteners for the panel and substrate, considering length, drilling capacity, corrosion protection and washer. Where fixing through a rib requires a saddle washer, use the correct type. A similar-looking ordinary washer is not a substitute; its shape must match the facing profile.

Fixing quantity comes from the design. Roof edges may need a different arrangement from the central area. Install screws perpendicular to the surface and compress seals correctly without crushing the facing. Main structural fixings and lap-stitching screws have different functions: stitching adjacent sheets does not replace fixing to a purlin.

Plan joints and cutbacks before ordering. A manufacturer’s 2026 catalogue describes cutbacks from 50 to 250 mm in 10 mm increments. This is a production range, not unrestricted choice on site. The correct length follows the eaves or lap detail and system documentation. Confirm the cutback side and installation direction as well.

After fixing the panels, install flashings to the specified details, including eaves, ridge, side edges and penetrations. Sealants must suit the coating and intended use. Foam is not an arbitrary replacement for all tapes. Rooflights and large openings need planned supporting members; cutting an opening changes panel behaviour.

Remove swarf and material residues. Check coating damage, fixing tightness, seal continuity, drainage and gutter terminations. Photograph details and retain product documents. The manufacturer’s instructions prohibit cutting panels with an angle grinder because of heat and coating damage.

Work within the safe conditions specified for the selected panel system and lifting equipment. Check wind limits, panel installation temperatures and sealant conditions separately; do not transfer limits between manufacturers. Stop if elements cannot be guided and fixed safely. Resolve deformation, loose connections and leaks before acceptance.

No. The general sequence may be similar, but joint details, fixings and permissible slopes depend on the system.

No. Flashings, seals, cleaning and detail inspection are still required. They often determine whether the roof is weather-tight.