What are the 4 types of plywood?
By exposure and use, the four common categories are interior, exterior, structural, and marine. Interior plywood uses an MR bond for dry indoor work; exterior and structural use a water-resistant bond for weather and load; marine adds a void-free core for wet service. Read the bond class (WBP vs MR) alongside the veneer grade (A to D).
What are the 3 types of plywood by ply count?
3-ply, 5-ply, and multi-ply. 3-ply is the thin, common board for light indoor work; 5-ply is a middle-weight interior board; multi-ply has seven or more veneers for structural strength in roofing and framing.
What are the plywood grades A, B, C and D?
They grade the face veneer. A is smoothest and near knot-free; D is roughest with open defects. A and B suit visible, paintable faces; C and D suit hidden structural work. Panels are often labelled with two faces, such as B/C. An X, as in CDX, signals an exterior-capable bond rather than a separate grade.
Which types of plywood are used in construction?
Softwood sheathing, structural (CDX-type) plywood, and OSB do most construction work — usually C or D faces with an exterior bond, chosen for strength rather than looks. Film-faced and overlay panels handle concrete formwork.
Is any plywood fully waterproof?
No. Plywood is water-resistant, not waterproof. Marine and WBP-bonded exterior panels resist moisture and delamination far better than interior board because of a void-free core and a weather-and-boil-proof glue line, but all plywood still needs sealing and correct grade selection for wet service.
