Moisture resistant plywood is generally used for indoor furnishings, wardrobes, wall panels and cabinets, where humidity will be encountered but rarely. Not all moisture resistant plywood is created equally. Lower grade boards may swell, warp, and/or delaminate after time passes.
What Moisture Resistant Plywood Is Designed For
It is important to know what moisture resistant plywood is designed for before you evaluate the quality. These boards are designed for indoor use, but they will not hold up under heavy moisture conditions. Use moisture resistant plywood in dry or semi-dry growing locations such as bedrooms, living rooms, or modular furniture; do not use in locations that are regularly exposed to water (e.g. basements, kitchens, bathrooms, etc.).
Check the Core and Veneer Layers
The core of a good quality moisture resistant plywood is the strongest part. Check for evenness of the veneer layers on the exposed edge of the sheet. High Grade MR plywood has very evenly stacked layers with minimal gaps. If the layers are unevenly layered or if there are air pockets between the layers, then the board will ultimately experience less durability than other MR plywoods.
The Adhesive Bond Strength and Quality
Adhesive bonding is one of the primary reasons that moisture resistant plywood has moisture resistance. Know the adhesive used in the moisture resistant plywood’s core. High Grade MR plywood uses strong synthetic resins that will prevent the laminates from separating during periods of increased humidity. Weak adhesive bonds can lead to delaminating during long term use.
Physically Test Cognitively
Performing a quick tap test can give insight to the internal quality of the moisture resistant plywood. Lightly tap the surface and a solid sound indicates that the plywood has a solid core. Hallow sounding plywood indicates that there could be gaps that would ultimately lead to weak spots.
Check Surface Condition
The finished surface of MR plywood should be smooth and polished, to allow other materials to properly adhere to it.
Certifications and Manufacturer Standards
Look for IS certification, manufacturer markings and the batch number. Moisture resistant plywood is required to undergo testing to ensure that it meets bonding and moisture resistance standards. If the plywood does not have appropriate markings or documentation, then do not purchase it.
Weight and Density
Moisture resistant plywood should feel balanced in weight; it should not be too light or too heavy. Extremely light weight boards are usually made with substandard wood or replaceable fillers that compromise the board’s strength and durability. Therefore, proper density should indicate that the manufacturer has used a good quality raw material and has followed production controls.
Purchase from a Reputable Manufacturer
Most of the moisture resistant plywoods are manufactured by well-respected companies. Well-respected companies such as Royale Touche produce moisture resistant plywood that can be trusted to perform and last well within an indoor environment.
