Exterior and Marine grade plywood explained
It's a very common mistake to describe exterior plywood as "marine plywood."
DIY and building shows on television seem to call any plywood "marine plywood." Over the years “marine” has become a generic term to describe plywood that is exterior rated.
Standard exterior plywood is bonded using an exterior phenol glue. The specification for this is EN314-2 Class 2. Previously termed "WBP" (Weather and Boil Proof). Plywood bonded with this glue will not delaminate, even after 72 hours in boiling water.
Often, when a client is asking for Marine plywood they actually mean WBP bonded exterior plywood. This is a relatively inexpensive product and can be softwood plywood, tropical hardwood plywood and birch plywood.
There are other types of WBP plywood available but these are the most common.
Genuine Marine plywood is normally used for the boat building industry or where the board is going to be in contact with water and moisture for a very long time. The standard for marine plywood is BS1088 - bond specification EN314-2 Class 3. Above this is "Lloyds Approved". The glue that's used to bond the veneers together is exactly the same glue as in WBP plywood.
The BS1088 standard comes from the types of timbers used in the make up of the plywood and the quality of the timbers used. Obviously in marine plywood more naturally durable timbers are used and the quality of these timbers and the manufacture of the board is better. Marine plywood is a lot more expensive than exterior plywood and is generally used in applications where the cost of a failure of a board would be extremely high. In these situations the initial higher price of the marine grade is justified in exchange for peace of mind.
If you require actual marine plywood, then please contact us.
If you require standard exterior plywood in commercial quantities, then please contact us too.