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Sheathing Plywood Class 3 Exterior Grade 2440mm x 1220mm | 12mm or 18mm

Original price £0
Original price £26.04 - Original price £35.34
Original price
Current price £35.34
£26.04 - £35.34
Current price £35.34

Our Class 3 Exterior Grade Sheathing Plywood is a high-quality, structural panel suitable for external wall sheathing, roofing, flooring, and general construction. Manufactured to meet EN 636-3 standards, this plywood is designed for use in humid and external conditions, offering strength, durability, and reliable weather resistance when correctly installed and protected.

✅ Board Size: 2440mm x 1220mm (8ft x 4ft)
✅ Available thicknesses: 12mm and 18mm
Class 3 rated — suitable for external structural use
✅ Manufactured from robust softwood or mixed hardwood veneers
✅ Ideal for roof decks, external walls, cladding backing boards, and site hoarding

This sheathing ply is intended for use behind weatherproof membranes or cladding systems and provides dependable structural performance under building standards.


🛠️ Typical Applications:

  • Roof decking under felt, EPDM, or membrane systems

  • External wall sheathing for timber frames

  • Floor decking for temporary or permanent use

  • Site hoardings and construction screens

✔️ Durable, versatile, and easy to cut and fix
✔️ Complies with EN 314-2 Class 3 glue bond
✔️ Suitable for projects requiring external-grade performance
✔️ Nationwide UK delivery available


🧠 Important Notes:

  • Although Class 3 sheathing ply is rated for external environments, it must still be correctly installed with waterproof membranes or protective finishes to ensure maximum lifespan.

  • Edges and cut surfaces should be sealed if exposed.

Pickup available at Alter Supplies

Usually ready in 2 hours

Alter Supplies & Contracting

4.9

93 reviews on

Caroline Clulow
September, 2025
This may sound crazy but, honestly, I've never had such good service. Young men, mostly, who were knowledgeable and so helpful. Don't google for wood, most places are very expensive. Pieces that were £15 on Google were £4 here. 1.8 metre slats at £1.20. Great company.
George Davies
August, 2025
Friendly polite staff nothing to much trouble fast home delivery service would recommend to everyone
Adam Plenderleith (RevRev)
August, 2025
Another delivery from Alter Supplies today. Amazing service even for a relatively small order. Timber and slabs delivered promptly by a very cheery young man! An easy 5* given!