How to choose a plywood grade without over-specifying
Boiling water proof everywhere is a waste of money. A short guide to matching grade to the actual condition.
The most common specification error in residential joinery is not under-specifying — it is buying marine grade board for a bedroom wardrobe that will never see a drop of water.
Grade is about the adhesive and the veneer quality, not about strength in the way most people assume. A boiling water proof board resists moisture ingress at the glue line; it does not make a shelf carry more weight. For load, look at thickness, core construction and span.
Work condition by condition. Anything within a metre of a sink, in a bathroom, or against an external wall in a humid city earns a BWP or IS 710 grade. Internal dry joinery does not — a BWR panel marked to IS 303 will serve it for decades.
One caveat worth the money: the carcass base of any kitchen unit. Floors get mopped, pipes weep, and replacing a base means pulling the whole run out. That is the one place we would always specify up.
