The short answer: An 18 mm thick OSB board weighs approximately 11 to 13 kilograms per square meter (about 2.3 to 2.7 lbs per square foot). A standard 4x8 foot sheet weighs roughly 33 to 39 kg (73 to 86 lbs).
18 mm OSB board weight by type
Oriented strand board (OSB) is an engineered panel of compressed wood strands. Weight scales with thickness and density.
| Sheet / measure | Typical weight |
|---|---|
| Per square meter (18 mm) | 11-13 kg/m² |
| 4x8 ft sheet (18 mm) | 33-39 kg (73-86 lbs) |
| 4x8 ft sheet (12 mm) | 22-27 kg (49-60 lbs) |
| 4x8 ft sheet (22 mm) | 40-48 kg (88-106 lbs) |
| Per square foot (18 mm) | about 2.3-2.7 lbs |
What affects 18 mm OSB board weight
- Thickness. The 18 mm grade is heavier than thinner OSB and lighter than thicker panels.
- Density. Denser boards weigh more for the same dimensions.
- Sheet size. Larger panels weigh more in total.
- Moisture content. OSB absorbs moisture, adding weight when damp.
- Resin and wax. The binder and waterproofing content affect density.
- Wood species. The type of wood strands used influences overall density.
How 18 mm OSB board weight compares
A standard 18 mm OSB sheet at around 36 kg weighs about the same as a large bag of cement, or roughly a medium-size dog.
Frequently asked questions
How much does a full sheet of 18mm OSB weigh?
A standard 4x8 foot sheet of 18 mm OSB weighs roughly 33 to 39 kg (about 73 to 86 lbs).
Is OSB lighter than plywood?
OSB is often slightly heavier than plywood of the same thickness, though it varies by product.
What is the weight of OSB per square meter?
An 18 mm OSB board weighs around 11 to 13 kg per square meter.
