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18mm Marine Plywood Sheets

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630 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

Collect from BN5 9XR: -

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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 / 5 630 reviews
John quinn, 10th December
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Quick despatch quality wood.
Verified, Collected by Cut My
Sarah Skeet 52103, 10th December
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Good quality ply, and a very fair price for the panels ordered.
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Tom Moth, 10th December
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Item was well wrapped came just about in time but had a nick right in the middle, not the end of the world but a tad disappointing
Verified, Collected by Cut My
John White, 10th December
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Supplied exactly as ordered, good service, will use again
Verified, Collected by Cut My
Ian Smith, 6th December
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Good value, exactly as described
Verified, Collected by Cut My
Mike Plowman, 4th December
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The birch ply is excellent and it was cut exactly as I specified.
Verified, Collected by Cut My
russ.anton.g, 4th December
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Pleased with this good work, many thanks!
Verified, Collected by Cut My
Andrew Welch, 3rd December
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I was going to buy a sheet, cut it (probably involving buying a jigsaw to cut it) but I got this instead, for way less money and hassle, and delivered in about five days! Millimetre perfect, too. Couldn’t be happier
Verified, Collected by Cut My
Mrs Woods, 1st December
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The cut was quite complicated but you cut it perfectly and it fits the space perfectly. Thank you very much.
Verified, Collected by Cut My
Mr Michael Glover, 1st December
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Delivery of the cut to size items was as stated, I was concerned it would be delayed as I had a particular time line due to time constraints, the goods came perfectly within my schedule. The items were very well packed to avoid damage. I can easily recommend Cut My and would use them again without hesitation.
Verified, Collected by Cut My
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