Is shuttering plywood waterproof?
No. Shuttering plywood is water-resistant under a WBP bond class, not waterproof. The phenolic film face and weather-and-boil-proof glue line are built for wet concrete, rain delays, and outdoor stacks between pours. They are not a permanent-immersion or marine warranty.
What does WBP mean on shuttering plywood?
WBP means weather and boil proof — a glue-bond classification tested under boil and moisture exposure, not a claim that the finished sheet is impervious forever. Extended submersion, open cut edges, and breached film still admit water. On an RFQ, write the bond class in plain text rather than the word waterproof.
Is Form Extra a Class 3 phenolic panel?
No. Form Extra uses Superior Glue MUF in the core, sits in EN 636-2, and is not Class 3, even though it carries the same phenolic face family as Form Basic. Phenolic Class 3 writing applies to Pro Form Lite, Pro Form, and the HDO range. Mixing those labels is how the wrong sheet arrives on site.
Can shuttering plywood be reused after it gets wet?
Yes, when the film face is intact and cut edges are resealed. Short weather exposure between pours is normal for a WBP shuttering programme. Panels stored in standing water or left with open saw cuts lose face life long before the glue line itself fails.
Does edge sealing really protect water resistance?
Yes. Cut edges are the first moisture path into film-faced shuttering plywood because water travels along end grain faster than through a sound face film. Seal every fresh cut before the next pour. Peeled corners and open nail holes create the same early failure, even on a Class 3 phenolic sheet.
How should I write bond class on a shuttering RFQ?
Name EN 636-2 MUF or EN 636-3 / Class 3 phenolic in plain text, then name the grade and overlay family. Add thickness, size, quantity, discharge port, and expected reuse as up to N. Ask for mill documents before deposit so the exposure calendar matches the glue class that ships.
