Weigh the sheet to verify density
A 1220x2440x18mm sheet at 550 kg/m³ core density should weigh approximately 29-30 kg. If the sheet weighs under 26 kg, the core is likely low-density poplar or under-pressed plies. Weigh three random sheets from the sample batch and average the result.
Film adhesion and surface inspection
The phenolic film should be uniformly dark brown, smooth to the touch, and free of bubbles, scratches or patch repairs. Try lifting a corner with a fingernail: poor adhesion peels easily; quality film resists mechanical separation. Check both faces if the specification calls for double-sided film.
Edge sealing and core inspection
Inspect the panel edge for consistent acrylic sealant coverage. The core plies should be visible as uniform layers without voids, overlaps or foreign material. Gaps between plies indicate poor pressing and predict early delamination under concrete pressure.
Glue line and certification checks
Request the mill test certificate before paying a deposit. Verify the glue line is listed as WBP phenolic (not MR or commercial urea). Cross-check the mill name on the certificate against the factory name on the packing list; mismatches suggest trader-relabelled stock.
Dimensional tolerance and flatness
Lay the sheet on a flat surface and check for warping or twist. Film-faced plywood for formwork should be flat within 2mm over a 2440mm length. Excessive bowing creates concrete fins and increases finishing cost on fair-faced work.