The main issue with using a non marine plywood is the eternal problem of time.
Boats cabinets laminated playwood.
Plywood is an engineered wooden product manufactured by bonding wood veneers with each other using an adhesive and high temperature and pressure.
Marine plywood construction boards if you ve got a big repair job that needs marine plywood teak lumber or fiberglass boards you ve come to the right place.
Given sufficient time and use it may be that the protective fibreglass layer becomes damaged allowing water to permeate the surface and begin to rot the underlying plywood.
If the plywood is required structurally then this becomes a messy problem indeed.
I would state in your contract that you can not warranty any laminate over a plywood substrate.
Plywood is normally sold in rectangular sheets of 4ft by 8ft 1220mm x 2440mm.
It is the water resistance of the type of glue used to laminate the piles which determines the grade of the ply as well as wood of the veneers.
If it calls for it in the plans ask the builder to call the architect or customer to see about changing it to mdf.
The more veneers that are used the stronger and stiffer the plywood becomes so for bending fewer is better.
Tricel honeycomb panels are as strong as plywood for bulk heads cabinetry and furniture.
Plywood is used for a plethora of interior exterior and structural applications.
Mdf is the way to go.