What grade of plywood is used for formwork?
Formwork plywood is graded on three parallel layers: face appearance (A–D or E–IV), bond class (EN 636-1/2/3 in Europe, Interior / Exposure 1 / Exterior in North America), and overlay performance (Plyform Class I/II in the US, EN 636-2/3 with film-faced or HDO/MDO overlays in Europe and globally). The right grade depends on the number of pour cycles, the moisture exposure, and the concrete finish required — not on the face appearance grade alone.
What is the difference between EN 636-2 and EN 636-3?
EN 636-2 (Class 2) panels are bonded with WBP melamine adhesive and rated for humid conditions and short exterior exposure. EN 636-3 (Class 3) panels are bonded with WBP phenolic adhesive and rated for full exterior service — prolonged wetting, alkaline concrete paste, freeze-thaw cycling. Class 3 panels carry the higher reuse-cycle ratings and are mandatory for high-reuse formwork and outdoor or wet-climate pours.
What does APA Plyform Class I mean?
APA Plyform Class I is the premium North American formwork grade — sanded face and back, group-1 species (Douglas fir, southern pine), Exterior bond. Often paired with HDO overlay for high-reuse and architectural fair-face concrete work. Class II is the mid-range alternative with broader species tolerance.
Is Plyform plywood the same as film-faced plywood?
No. Plyform is the APA's North American classification for concrete-forming plywood and refers to the structural grading and bond rating of the panel — with optional HDO or MDO overlays. Film-faced plywood is the global term for plywood with a phenolic or melamine film overlay, common across Europe, Asia, Australia, and the Middle East. A panel can be both (HDO-overlaid Plyform Class I) or one without the other (a phenolic film-faced panel that doesn't carry APA Plyform certification).
What grade is shuttering plywood?
"Shuttering plywood" is the UK and Indian trade term for formwork plywood. In the UK, shuttering plywood typically refers to EN 636-2 or EN 636-3 panels, often film-faced. In India, shuttering plywood is graded under BIS IS 4990 with BWP (boiling-water-proof, equivalent to EN 636-3) and BWR (boiling-water-resistant, equivalent to EN 636-2) bond classes.
Can I use B/BB plywood for concrete forms?
Only if the bond class is appropriate. B/BB describes the face/back appearance grades — the bond chemistry between veneers is a separate specification. B/BB-faced plywood with EN 636-1 (interior bond) will fail rapidly in formwork service. B/BB-faced plywood with EN 636-2 (Class 2 melamine) is suitable for short-cycle indoor commercial pours; B/BB on EN 636-3 (Class 3 phenolic) is suitable for full exterior formwork service. Always read the bond class on the spec sheet, not just the face grade.
What standard does formwork plywood need to meet in the UK?
UK formwork plywood must carry CE marking under EN 13986 with bond class declaration (EN 636-2 or EN 636-3 for formwork applications), formaldehyde class E1, and Declared Performance values for bending strength and stiffness. UK construction project specifications historically referenced BS 8110, now superseded by Eurocode 2 (BS EN 1992-1-1) which itself references EN 13986 for panel performance. The practical specification is the EN 636 bond class.
How many reuses do you get from each formwork grade?
Reuse counts depend on overlay type, bond class, and care. Typical maximum ranges with proper handling: B-B Plyform / unfaced EN 636-2 panels — up to 5 pours. MDO Plyform / EN 636-2 melamine film-faced — up to 8–12 pours. Plyform Class II / 120 g/m² phenolic film-faced — up to 15 pours. HDO Plyform / 220 g/m² phenolic film-faced (Pro Form) — up to 20 pours. All values are maximums under good care.
