What it is called, by market
One concept, four markets. Where a name means something else locally, the card says so rather than leaving you to find out on site.
United Kingdom
Same word, different thingOSB
also oriented strand board, sterling board
British "chipboard" means the fine-particle furniture and flooring panel, NOT OSB — so a substitution between them swaps a structural board for one that is not.
United Statesyours
Same word, different thingOSB
also oriented strand board, sheathing
American "particle board" is the fine-particle panel British usage calls chipboard; the word chipboard is uncommon there and can be read as either.
Canada
Close, not identicalOSB
also waferboard, particleboard (the fine panel)
Waferboard is an older related product with larger, unoriented flakes — structurally weaker than OSB and not a synonym for it.
Australia
Close, not identicalOSB
also structural particleboard, chipboard flooring
Australian practice uses structural particleboard for flooring far more than OSB, so the common sheet in a floor is a different product from the North American default.
The governing standard, by market
United Kingdom
BS EN 300
Oriented strand boards — definitions, classification and requirements.
United States
PS 2 / APA rating
Performance standard for wood structural panels, with span ratings.
Calculators for this
Each works in either measurement system, and the terminology on the page follows whichever market you have selected.
Frequently asked questions
- Is chipboard the same as OSB?
- Not in British usage, and the difference is structural rather than cosmetic. OSB is made from large wood STRANDS laid in oriented layers and bonded under pressure, which gives it directional strength and stiffness suitable for sheathing walls and roofs and for structural flooring. Chipboard, in British usage, is made from small particles with no orientation, which makes it dimensionally convenient and considerably weaker — it is the panel used for furniture carcasses and for some flooring grades. Substituting one for the other because both are described as engineered wood panels puts a non-structural board where a structural one was specified, and it is the moisture behaviour that usually reveals it first.
- What does a span rating tell you?
- The maximum spacing of supports the panel is rated for, which is the property that actually matters when sheathing or decking. North American structural panels carry a rating that names the permitted spacing for roof and floor use, so a sheet can be selected against the framing centres directly rather than by thickness alone — two panels of the same thickness from different products can have different ratings. European and British practice specifies the board by its grade and its structural class instead, with load-span tables published separately. Either way, thickness on its own is not a specification: it is the rating or the class, against the support spacing and the load, that decides whether a panel is adequate.
- How do these boards behave when they get wet?
- Differently, and it is the property that most often decides which is acceptable. Standard chipboard and particle board swell substantially and largely irreversibly when wetted, particularly at cut edges, and they lose strength as they do — which is why a flooded floor of standard board is replaced rather than dried. OSB swells too, mostly at the edges, but generally retains more of its strength and is manufactured in grades intended for humid conditions and for temporary exposure during construction. Moisture-resistant grades of both exist and are a specified product rather than a general property. None of them is a waterproof board, and none should be left exposed to weather beyond the period its grade allows.