Delamination
Delamination is the separation of bonded layers in a laminated material — in plywood, it means the adhesive bond between veneer plies has failed, causing the plies to separate and compromising the panel's structural integrity.
In Detail
Delamination in Wood Panels
Delamination occurs when the adhesive bond between layers in a laminated panel fails, allowing the layers to separate. In plywood, this means veneer plies peel apart. In OSB, the equivalent failure mode is strand separation, though it is technically not delamination since OSB is not laminated in the traditional sense.
Common causes of delamination include:
- Prolonged moisture exposure that exceeds the panel's adhesive rating (Interior-rated panels exposed to weather)
- Manufacturing defect — insufficient adhesive, inadequate press pressure or temperature
- Excessive heat exposure (fire or proximity to heat sources)
- Chemical exposure that attacks the adhesive bond
Delaminated panels must be replaced — there is no field repair. A delaminated structural panel has lost its load-bearing capacity and is a safety concern in structural applications like shear walls and roof diaphragms.
Related Terms
Exposure 1
Exposure 1 is a plywood adhesive classification indicating the panel uses waterproof glue that will not fail from moisture, but the panel is designed for temporary construction moisture exposure — not permanent outdoor use.
Edge Swell
Edge swell is the permanent expansion of panel edges — particularly OSB edges — that occurs when the panel absorbs moisture, creating raised ridges at panel joints that telegraph through roofing, flooring, and other finish materials.
Related Materials
CDX Plywood
This is a test description for CDX plywood as we work on the technical backend of the website.
Marine Plywood
Marine plywood is a premium plywood panel manufactured with waterproof adhesive and void-free core veneers, designed for permanent or chronic moisture exposure in boat building, dock construction, and marine-adjacent structural applications.