If you’re planning bathroom cabinets, you’ve probably heard two opposite pieces of advice:
One person says,
“Always use WPC. It’s 100% waterproof.”
Another says,
“No, no… good BWP plywood lasts longer and is stronger.”
So which one is right?
Bathrooms are the harshest environment for any wood-based material.
There’s moisture every day, steam, wet floors, and sometimes small leakages nobody notices until it’s too late. This test shows what really happens when the material stays in water for several days , similar to actual bathroom conditions.
What is BWP Plywood?
BWP = Boiling Water Proof
This is IS 710 marine-grade plywood made with:
• Hardwood veneers
• PF resin (phenol formaldehyde)
• Strong bonding
• Anti-borer treatment
It is highly resistant to water but not fully waterproof.
In soaking conditions, plywood will show some swelling but remains structurally strong — if it’s high-quality BWP.
The 72-Hour Water-Soak Test Setup
To keep the comparison fair:
• One piece of 18 mm WPC board
• One piece of 18 mm BWP plywood
• Both cut to the same size
• Both submerged completely in a bucket of water
• Duration: 72 hours (3 days)
• Temperature: Normal room temperature
• Laminate not applied (to test raw core behavior)
Test Results After 24 Hours
BWP Plywood (After 24 Hours)
• Slight swelling at the edges
• Slight softening
• No delamination
• Shape intact
• Still very strong when pressed
WPC Board (After 24 Hours)
• Absolutely unchanged
• No swelling
• No softening
• Same weight and feel
Winner for 24 Hours:
WPC board (as expected)
Test Results After 48 Hours
BWP Plywood (After 48 Hours)
• Slight increase in swelling (1–2 mm)
• Color darkens slightly
• No layers separating
• Edges feel a little raised
• Center area still solid
WPC Board (After 48 Hours)
• No change in thickness
• No shape change
• No warping
Winner for 48 Hours:
WPC board
But plywood still holding strong.
Test Results After 72 Hours
BWP Plywood (After 72 Hours)
• Noticeable swelling at edges (2–3 mm in some areas)
• No peeling or layer separation
• Still strong internally
• After drying for 24–48 hours, most swelling goes down but edges remain slightly raised
WPC Board (After 72 Hours)
• Zero swelling
• Zero expansion
• Zero shape change
• Same as when it went into water
But Water-Soak Isn’t the Full Story
(Strength & Practical Use Matter Too)
If bathrooms had only water and no weight or hardware, WPC would win in every home.
But bathroom cabinets need to:
• Hold weight
• Mount on walls
• Take hinges
• Hold drawers
• Support heavy items like buckets, bottles, cleaners
This is where plywood performs differently.
Strength Test: Which One Is Stronger?
WPC Board Strength
• Softer material
• Screws loosen over time unless special anchors are used
• Hinges may sag with heavy shutters
• Large cabinets may bend slightly at the bottom
• Not ideal for very heavy loads
BWP Plywood Strength
• Very strong
• Holds screws well
• Ideal for heavy cabinets and drawers
• Handles wall-mounts easily
• Takes hardware without issues
Strength Winner:
BWP Plywood
Screw Holding Test
WPC
• Screw threads hold weakly
• Strips easily if tightened too much
• Requires stainless steel or special screws
• Hinges on WPC need extremely careful installation
Plywood
• Excellent screw grip
• Supports hinges and channels long-term
• Works with all normal hardware
Winner:
Plywood
If we judge only by water soaking, WPC board wins easily.
But if we judge overall suitability for bathroom cabinets, BWP plywood often performs better in real life because:
• It is stronger
• It holds screws properly
• It supports heavy loads
• It works with all hardware
• Finishing is smoother
Best Real-Life Choice:
BWP plywood with WPC only at base or wet-touching zones
