Plywood is a staple in many construction and woodworking projects, but in marine environments or cold storage spaces like refrigerated ships, ordinary plywood won’t do. That’s where BWP plywood—Boiling Water Proof plywood—comes in. Let’s explore what it is, its properties, and why it’s ideal in ship flooring, boat building, and refrigerated ship linings.
What is BWP Plywood?
- Definition: BWP plywood refers to plywood treated and manufactured such that its layers bonded with waterproof/boil-proof adhesive (often phenolic resin), enabling it to resist exposure to boiling water without delamination or structural failure.
- Standard: In many places (incl. India), there is a specification (for instance IS:710) that defines marine plywood / BWP plywood standards.
- Construction: Typically comprises multiple veneer layers (plies) of hardwood or treated woods; glue/resin between plies is very strong and water-resistant. Surface and core are often treated to resist fungal attack, termites, warping etc.
Key Properties
Here are the features that make BWP plywood especially suited to harsh, wet, or temperature-sensitive environments:
| High Water Resistance / Boiling Water Resistance | Does not delaminate, warp or deteriorate even under repeated water exposure |
| Dimensional Stability | Dimensional Stability |
| Resistance to Biological Decay & Pests | Resistance to Biological Decay & Pests Resists fungal decay, termites, borers, especially with chemical treatments |
| Good Finish & Workability | Can be cut, shaped, laminated, sealed, etc. for aesthetic and functional surfaces |
Key Properties
Let’s look specifically at three demanding applications: ship flooring, boat building, and refrigerating ship linings. For each, we’ll see why BWP plywood is often a top pick.
1. Ship Flooring
Ship decks and internal flooring present several challenges:
- Constant exposure to moisture / spray / condensation
- Heavy foot traffic, load from cargo etc.
Variation in temperature and humidity
How BWP helps:
- Its high water resistance prevents swelling, rot, and delamination caused by water ingress.
- Dimensional stability means joints, fixtures, and coverings stay tight; fewer gaps even when wood moves.
- Resistance to fungal and pest attack is especially important in saltwater/marine environments.
Ability to take finishes, anti-slip coatings, etc. makes BWP suitable for exposed floors or gangways.
2. Boat Building (Hull, Decks, Interiors)
Boat structures are continuously exposed to water: hull surfaces, frames, interior panels near wet zones.
Advantages of using BWP:
- Hulls often see continuous wetting. BWP plywood resists water penetration better than standard plywood; this extends lifespan and reduces maintenance.
- In lightweight boats or vessels, plywood often forms bulkheads, deck modules, cabin furniture. Using BWP ensures that these parts don’t deteriorate prematurely.
Reduction in warping / swelling helps maintain structural integrity and sealing (i.e., watertightness).
3. Lining of Refrigerated Ships (“Reefers”)
Refrigerated ships have special demands:
- Interior cold temperatures with high humidity; condensation can be a problem.
- Surfaces often come into contact with water due to frost, thawing, washdowns.
- Insulation and linings need low thermal expansion, good bonding so that the linings remain sealed and efficient.
Benefits of BWP for refrigerated ship linings:
- By resisting moisture, BWP plywood avoids rot/mold which could compromise hygiene and structural safety.
- Stable dimensions under cold and then warming help avoid cracks or gaps through which moisture or pests could enter.
- Compatible with adhesives, coatings, maybe composite skins used in cold store panels.
Challenges / Considerations
While BWP plywood is strong and highly suited for these applications, it’s not without cost or limitation. Here are things to keep in mind:
- Cost: Typically more expensive than MR (Moisture Resistant) or standard plywood due to better adhesives, treatments, higher quality veneers, stricter quality control.
- Weight: Depending on species and thickness, may be heavier; under-designing support structures or using too thin ply can lead to issues.
- Certification and Quality Control: It’s critical to ensure you are getting true BWP plywood—look for certifying marks (e.g., IS:710 or equivalent), good manufacturer reputation, test data. Poor glue or low resin content may mean a product labelled “BWP” doesn’t perform.
- Maintenance: Though more durable, finishes should still be maintained (paint, varnish, sealants), joints sealed, regular inspections for damage.
