Thickness selection by pour element
Wall and column shutters typically use 12mm or 15mm film-faced plywood backed by steel waler systems. Slab soffits and table forms use 15mm or 18mm to handle the longer span between joists. For heavy raft foundations and thick walls, 18mm to 21mm panels reduce deflection and improve finish quality. Consultants should specify thickness in the shutter drawing notes, not leave it to the subcontractor.
Across UAE and KSA high-rise projects, 18mm has become the default slab thickness because it balances weight, handling, and span capacity on H20 timber joists at 400mm centres.
Core selection: hardwood, combi and poplar
Hardwood cores (eucalyptus, keruing) deliver the highest density (550-650 kg/m³) and the longest reuse cycles. They are the consultant's choice for architectural exposed concrete and long programmes. Combi cores (hardwood face veneers with poplar inner plies) offer a mid-range compromise at 500-580 kg/m³. Poplar cores (400-480 kg/m³) are lighter and cheaper but suited to short-duration or non-critical pours.
Specifying core type by density range rather than species name reduces substitution risk on site.
Film weight and concrete finish class
Standard phenolic film weights are 120 g/m², 220 g/m² and 240 g/m² per face. For general structural concrete hidden behind plaster, 120 g/m² is adequate. For fair-faced and architectural concrete where the shutter imprint becomes the finished surface, 220 g/m² is the minimum consultants should specify. Superform-grade 240 g/m² film delivers Class A finishes on repeated pours.
The film should be smooth, non-porous and free of scratches at delivery; consultants can request a sample panel for approval before bulk order.
Glue line and standards compliance
WBP (Weather and Boil Proof) phenolic glue lines to EN 314-2 Class 3 or BS 6566 Part 8 are the minimum for GCC outdoor formwork. MR (Moisture Resistant) melamine-urea glue is acceptable only for protected indoor shutters. Consultants should reference the glue standard explicitly in the specification, not assume the supplier will default to WBP.
For projects requiring third-party certification, specify mill test certificates showing glue shear strength and boil-test results.
Edge sealing and on-site durability
Unsealed edges are the single largest cause of premature delamination on GCC sites. Consultants should specify waterborne acrylic edge sealant applied at the factory and re-sealed after every panel cut on site. The specification should state "all cut edges to be re-sealed within 24 hours" to protect against UAE summer humidity and concrete bleed water.