IS 710 : 2010Marine Plywood - Specification

IS 710:2010 is the specification for marine plywood (BWP — boiling-waterproof grade) — the highest-durability structural plywood, for permanently or frequently wet, structural and high-reuse applications: boat building, marine and waterfront work, heavy-duty concrete shuttering/formwork, exterior structural panels and humid-environment joinery. Where IS 303 is general-purpose plywood, IS 710 is the marine/structural grade.

It is read with the plywood and formwork stack:

• IS 303 — plywood for general purposes (the lower, non-marine grade)
• IS 1734 (parts) — methods of test for plywood (the acceptance methods)
• IS 848 — synthetic resin (phenolic) adhesives for plywood
• IS 4990 — plywood for concrete shuttering · IS 456 — the concrete that formwork shapes

IS 710 is defined by a far more demanding set of requirements than general plywood:

• BWP bond — phenol-formaldehyde (PF) resin, with a severe 72-hour boiling-water glue-adhesion test (vs the milder BWR test of IS 303)
• Timber species — only specified, durable hardwood species permitted for the veneers
• Preservative treatment — mandatory chemical preservative treatment for biological durability (borer/fungus)
• Higher mechanical properties — minimum modulus of rupture and modulus of elasticity (it is a *structural* board), plus glue-shear strength
• Tight construction quality — limited permissible defects, good bonding, low moisture content

The marketing term 'BWP' legitimately belongs to IS 710; 'BWP/BWR' on a IS 303 board is not the same thing. A correct specification calls up *IS 710*, the thickness, and the ISI licence, and verifies it by the IS 1734 boil test on the delivered lot.

Scenario: 18 mm IS 710 plywood for architectural-concrete shuttering needing many reuses.

Step 1 — spec: call up IS 710 BWP, 18 mm, film-faced if a high-quality concrete finish is required; ISI-marked.

Step 2 — sampling: draw boards per the IS 710/IS 1734 sampling plan from the delivered lot.

Step 3 — the decisive test — 72 h boil: subject specimens to the IS 1734 72-hour boiling-water cycle then knife/glue-shear test. A true IS 710 board survives; an IS 303 'BWR' board passed off as marine fails here — this single test catches the most common substitution fraud.

Step 4 — mechanical + moisture: MOR/MOE meet the IS 710 minimums; moisture content within limit; preservative treatment evidenced.

Step 5 — verdict & use: accept only lots passing the boil + mechanical tests; for formwork, expect many more reuses than general ply, protect edges, and re-inspect for delamination between pours. The boil test, not the stamp, is the acceptance.

1. Accepting IS 303 'BWP/BWR' as marine ply. The grades and the boil test differ fundamentally — only an IS 710 board passes the 72-hour boil; insist on it and test the lot.

2. Specifying 'marine ply' with no IS 710 + ISI call-up. You receive a cheaper general board with marine branding; state the standard and verify.

3. No lot boil test. The ISI mark alone is regularly abused — the IS 1734 boil/glue-shear test on the delivered material is the only reliable check.

4. Using it but ignoring edge sealing. Even marine ply degrades through unsealed cut edges in wet/formwork use — seal edges and detail to shed water.

5. Over-specifying IS 710 for dry interior joinery. It is expensive; for dry interior non-structural work, IS 303 MR/BWR is the economical correct grade — match grade to exposure both ways.

• IS 303 — plywood for general purposes (non-marine grade)
• IS 1734 (parts) — methods of test for plywood (the 72-h boil test)
• IS 848 — synthetic resin (phenolic) adhesives for plywood
• IS 4990 — plywood for concrete shuttering work · IS 5509 — fire-retardant plywood
• IS 5539 — preservative-treated plywood · IS 2380 — particle/fibre-board tests
• IS 456 — RCC (formwork surface-finish requirements)

IS 710:2010 is a reasonably current revision and remains the benchmark for marine/structural/high-reuse plywood; the persistent industry problem is not the standard but grade fraud — general IS 303 ply sold as 'marine/BWP/710-grade'. The only reliable defence on a project is to specify IS 710 + thickness + ISI licence number and run the IS 1734 72-hour boil/glue-shear test on the delivered lot, not the sample board.

For formwork economics, genuine IS 710 (or film-faced IS 710/IS 4990) delivers many more reuses and better concrete finish than general ply, so the higher unit cost is usually justified on cost-per-pour for repetitive work — but only if it is actually marine grade. Match the grade to the exposure in both directions: IS 710 where it is wet, structural or high-reuse; IS 303 where it is dry interior — over-specifying marine ply for dry joinery just wastes money.