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18mm Marine Plywood Sheets

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723 reviews
Rated 4.7 out of 5 stars
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18mm Marine plywood is a durable material which is ideal for external and moisture-prone areas. From storage to walls, it resists fungi and delamination. Our high-quality BB/BB grade marine plywood sheets suit gardens, bathrooms, and parks.

Please note that the colour of your marine plywood may differ slightly from the images as we buy from multiple suppliers.

Shop for your plywood sheets cut to size, with additional options for rounded corners, lacquering, cutouts and more

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mm
Min: 100mmMax: 2440mm
mm
Min: 50mmMax: 1220mm

Approximate Weight: 64.00 g

Free delivery when you spend £250+

Estimated delivery: from Check My Postcode

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Key Features

Our 18mm marine plywood is engineered to endure demanding outdoor applications, from boat-building to docks, trailer beds, and heavy-duty construction projects.

Made to Resist Water

Every component of our marine plywood is designed for strength and moisture resistance. It uses high-grade hardwood veneers that resist fungal decay. A waterproof adhesive bonds the layers to prevent delamination, even after years in the elements. Minimal gaps between veneers act as a barrier against water absorption.

Exceptional Strength and Workability

The 18mm thickness provides extra rigidity and stability for a solid building foundation. The added thickness also allows for clean cuts, drilling, and hardware installation without splitting. The cross-banded construction minimizes wood grain misalignment for splinter-free edges.

Ideal for Wet Areas

Marine plywood is perfect for damp areas prone to splashing or spills like bathrooms, laundry rooms, kitchens, wet bars, and pool houses. For boat-building and waterside structures, marine plywood far outlasts standard plywood.

Robust Structural Support

The thick 18mm plywood offers pronounced structural integrity for heavy-duty applications like workbenches, scaffolding, stage platforms, and trailer beds. It provides sturdy support without excessive weight.

Outperforms Standard Plywood

Our marine plywood surpasses standard plywood in strength, water resistance, and reliability. The layered construction resists delamination, warping, and fungal decay better than standard plywood. For marine and outdoor use, marine plywood is the clear choice.

Applications

For heavy-duty construction projects

  • Boat hulls and decks
  • Dock and pier decking
  • Trailers and ramps
  • Outdoor furniture and structures
  • Subfloors and flooring

Around areas exposed to moisture:

  • Bathroom vanities and cabinets
  • Laundry and utility rooms
  • Kitchen cabinetry and islands
  • Wall sheathing and roofing
  • Wet bars and pool houses

For structural support and stability:

  • Shelving
  • Workbenches
  • Stage platforms
  • Scaffolding
  • Formwork

Marine Ply Board Specifications

Material Plywood
Finish Marine
Thickness 18mm
Maximum Sheet Size 2420mm x 1220mm
Minimum Sheet Size 100mm x 50mm
Plywood Grade BB/BB
Manufacturers Tolerances +/- 10 % plus 0.4mm (e.g. 5mm cast sheet could vary from 4.1mm to 5.9mm)
Cutting Tolerances +/- 1mm

Frequently Asked Questions

What plywood thickness should I use?

Consider your project. For light crafts, use 4mm ply. For cabinet backs, 6mm plywood. For furniture and shelves, 9mm ply to 12mm plywood should be used, based on load needs. For heavy-duty uses like flooring, we suggest using 18mm ply board.

Is marine plywood waterproof?

No, but it has minimal gaps between layers to reduce water absorption. This provides strength.

How is marine plywood different?

It uses better wood, more layers, durable adhesive, and resists delamination and warping in wet conditions, unlike regular plywood.

What's the best way to seal marine plywood?

Use a penetrating waterproof epoxy, as it soaks deep into the wood and needs less maintenance.

When should I use marine plywood?

Anywhere your plywood will be near water since marine plywood is designed for moisture resistance.

How long does marine plywood last?

With care, over 25 years even with constant water exposure. Sealing and painting increase lifespan.

Is marine plywood chemically treated?

No, it gets water resistance from quality wood, adhesive, and laminated layers - not chemicals.

Delivery depends on the size of your order

Reviews

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4.7 / 5 723 reviews
Benjamin, 14th May
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Good quality and super efficient delivery, would recommend.
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Christopher, 13th May
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I was very pleased with the plywood sheet !
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David A, 12th May
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Quick Delivery and very accurate cuts. Perfect
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Shaun Lamb, 7th May
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Table top looks great in our van. A light sand and some natural varnish. Looks so professional.
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Paul, 7th May
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000808638 is my order number. I ordered on 17th April and still havent recieved my order. I emailed on 3rd May and still not had a response. The product itself is good but the customer service and communication is appaling. Im still awaiting my order...
Verified, Collected by Cut My
MARIA MARBELL, 6th May
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All cut to size and delivered fast.
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Home Shaw, 3rd May
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Promise much, delivered poorly
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Robert Yates, 2nd May
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Awful quality. Full of voids and delaminations.
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Scott Minshall, 30th April
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Its wood it was good
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JGR, 29th April
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Outstanding.
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