Inspecting industrial building flashings before the cladding crew leaves site

On a large building, identify photographs by grid line and detail number so each inspection can be traced to its location. Assess the work against the approved drawings and the materials actually supplied. Resemblance to a detail on another building is not evidence that this one was built correctly.

Check material, thickness, folded section, lengths and quantities. Match verge trims to the panel thickness and gable arrangement and starter profiles to the wall-base detail. For bespoke items, make sure the drawing is the correct revision, particularly where dimensions changed during construction.

Identify the coated face and check mirrored items. A piece folded the wrong way may expose the reverse surface; where the two faces have different purposes this is more than a cosmetic defect. Confirm galvanised, aluminium-zinc-coated and colour-coated sheets from the documentation rather than appearance alone.

Follow the route from ridge caps, valleys and verge ends to the gutter aprons. Inspect laps wherever the direction changes. A reversed lap or a pocket can direct water behind a cover. Ends at eaves and corners often reveal more than a long straight stretch of neatly folded metal.

On the walls, examine opening surrounds, corners and plinths. Assess chimney and service penetrations against their individual details. A large bead of visible sealant is not a sign of quality on its own: the product, its position and the shape of the junction must work together.

Checking the covers does not establish that the main panel fixings are correct. Verify that the panels are attached to the specified substrate as designed, then check the separate flashing attachments. A thin trim cannot correct a missing support or a poorly fixed panel.

Check fastener type, spacing and condition. An overtightened washer or distorted sheet may require correction. Do not add screws wherever a surface happens to be accessible. Where the detail allows thermal movement, verify that the installed connections can still move as intended.

Remove filings, offcuts and loose metal fragments; they can stain or damage the cladding. Look for trapped protective film at laps and fixings as well. Remove it as directed for the sheet, rather than leaving it as permanent protection for the building.

Inspect surfaces for scratches and dents. The appropriate repair depends on the coating and the extent of the damage. A local touch-up does not restore a deformed section or replace corroded sheet. Distinguish a removable mark from a defect that requires replacement, and record the location and scope of each agreed repair.

Hand over records of the materials, coatings, seals and significant changes from the design. Retain fabrication drawings for special flashings so replacements can be ordered without measuring the original folds again. Identify the locations that need periodic cleaning and inspection.

Explain how to check outlets, joints and surfaces without damaging them. Set inspection intervals to suit the building’s exposure and the material supplier’s recommendations. The handover record provides a baseline for distinguishing later wear from an installation defect and choosing a suitable repair.