Not all OSB is the same. Different grades and thicknesses are designed for different applications. Understanding the options helps you choose the right product and avoid overpaying.
Common Thicknesses of OSB
Thickness (mm) | Common Named | Applications |
6mm (1/4") | Underlayment | Lightweight panels, packaging, displays |
9mm (3/8") | Sheathing | Wall sheathing, roof sheathing |
12mm (15/32") | Flooring base | Subflooring, structural panels |
15mm (19/32") | Heavy subfloor | Subflooring, industrial packaging |
18mm (23/32") | Structural | Roof decking, heavy-duty sheathing |
OSB Grades (North American Standard)
Grade | Descriptions | Applications |
Exposure 1 | Designed for construction use, can withstand some moisture during building | Wall sheathing, roof decking, subflooring
|
Exposure 2 | For interior use only, not recommended for prolonged moisture | Furniture components, packaging |
Exterior | Fully waterproof with exterior resin, suitable for direct weather exposure | Structural panels, outdoor uses
|
OSB Grades (European Standard)
Grade | Descriptions |
OSB/2 | Load-bearing boards for dry conditions |
OSB/3 | Load-bearing boards for humid conditions |
OSB/4 | Heavy-duty load-bearing boards for humid conditions |
Common OSB Panel Sizes
² 1220 x 2440 mm (4 x 8 feet) — most common
² 1220 x 3660 mm (4 x 12 feet) — less common
² 1250 x 2500 mm — European size
How to Choose OSB
Applications | Thickness (mm) | Grade |
Wall sheathing (residential) | 9mm or 11mm
| Exposure 1 or OSB/3 |
Roof decking | 11mm or 12mm | Exposure 1 or OSB/3 |
Subflooring | 15mm or 18mm | Exposure 1 or OSB/3 |
Heavy-duty flooring | 18mm or thicker | Exposure 2 or OSB/2 |
Outdoor structural use | 15mm or thicker | Exterior or OSB/4 |
Packaging and displays | 6mm to 9mm | Exposure 2 or OSB/1 |
Important Note
OSB edges can absorb moisture if left exposed. For applications where edges may be exposed to damp conditions, edge sealing is recommended. For long-term outdoor use, proper sealing or covering is necessary.
At Acepro, we supply OSB in multiple thicknesses and grades. Contact us for samples, specifications, or a quote.
