OSB3 Board – Structural OSB Boards 2440 x 1220mm, 9mm, 11mm & 18mm, OSB Sheathing Board for Flooring, Roofing & Walls
OSB3 Board – Structural OSB Boards 2440 x 1220mm, 9mm, 11mm & 18mm, OSB Sheathing Board for Flooring, Roofing & Walls
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Buy our structural OSB3 boards in the standard 2440 x 1220mm (8 x 4ft) sheet size, in 9mm, 11mm or 18mm thickness — engineered OSB board for load-bearing use in flooring, roofing, wall sheathing, sheds and timber-frame builds.
Manufactured to EN 300 from cross-layered wood strands bonded with water-resistant resin, OSB3 delivers consistent strength, excellent screw-holding and moisture resistance for humid conditions.
Choose Your Thickness
9mm OSB board — lightweight and versatile for internal linings, shed walls, hoardings, van interiors and general sheathing.
11mm OSB board — the balanced mid-range for roofing, timber-frame sheathing, garden buildings and shelving.
18mm OSB board — heavy-duty for subfloors, loft boarding, racking and load-bearing work with minimal flex underfoot.
| Specification | 9mm | 11mm | 18mm |
|---|---|---|---|
| Board Size | 2440 x 1220mm | 2440 x 1220mm | 2440 x 1220mm |
| Grade | OSB3 (EN 300) | OSB3 (EN 300) | OSB3 (EN 300) |
| Moisture Resistance | Yes | Yes | Yes |
| Load Bearing | Light-duty | Medium-duty | Heavy-duty |
| Typical Uses | Linings, shed walls, hoarding | Roofing, sheathing | Flooring, lofts, racking |
| Approx. Weight | 16kg | 20kg | 30kg |
| Fixing | Screws, nails or panel adhesive | Screws, nails or panel adhesive | Screws, nails or panel adhesive |
Related Boards & Timber
Compare with our MDF boards and hardwood plywood, or browse all timber & sheet materials.
Delivery
Free UK mainland kerbside delivery on OSB orders, shipped by pallet or large-item courier. Store boards flat and dry, away from moisture.
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FREQUENTLY ASKED QUESTIONS
What is OSB3 and how is it different from regular OSB?
OSB3 (Oriented Strand Board Type 3) is a structural-grade board manufactured to EN 300. Unlike standard OSB, OSB3 is engineered for load-bearing use in humid conditions, making it suitable for roofing, flooring and external sheathing where moisture resistance is essential.
Can these boards be used outside?
Yes — OSB3 is moisture-resistant and can be used in external applications such as sheds, hoardings and roofing. If exposed directly to the elements it should be sealed or painted and protected with suitable waterproofing or cladding.
What's the difference between 9mm, 11mm and 18mm OSB?
9mm – lightweight, ideal for internal linings, signs, van walls and temporary hoardings.
11mm – a balanced general-purpose board for roofing, timber-frame sheathing and shed walls.
18mm – heavy-duty strength for subfloors, loft boarding, racking and load-bearing work.
Can I cut and drill OSB3 boards easily?
Yes. OSB3 works with standard woodworking tools — it cuts cleanly, holds screws well, and can be nailed or bonded with panel adhesive.
Are these OSB boards suitable for flooring?
18mm OSB3 is the most suitable thickness for flooring, including loft floors and subfloors, giving the rigidity and load-bearing capacity to prevent flexing or squeaking.
Do the boards come treated or unfinished?
They are untreated with a smooth, unsanded finish. For exposed or decorative use, prime, paint or seal the surface.
Is OSB3 eco-friendly?
Yes — OSB3 is typically FSC or PEFC certified from responsibly sourced timber, and production makes efficient use of wood strands and offcuts.
How should I store the boards before installation?
Store OSB flat and dry, ideally indoors or under cover, away from water and with good ventilation to prevent moisture absorption or warping.
Do you offer delivery and how are the boards packaged?
Yes — nationwide kerbside delivery across mainland UK, with boards securely palletised or wrapped for safe arrival on site.
MONEY BACK GUARANTEE
Here at Rackerman, we take customer satisfaction very seriously. If you are unsatisfied with the quality of your product, please email us info@rackerman.co.uk or give us a call: 01665 497513 and we will make it right.
SHIPPING
It should take no longer than 1-2 business day to process your order, then 3-5 working days (5-10 working days on RSJs + Chippings) to then receive your order from us after dispatch.
If you haven't received your items in this time frame, please contact us.
RETURNS
If you are unsatisfied with your purchase, that's completely fine! We offer a 30 day money back guarantee to all customers, no questions asked! Please contact us to arrange a return.