Choosing the right board for a DIY project is usually a toss-up between OSB and plywood. Both have a lot to offer, are readily available and offer power, versatility and value.
While there is crossover that both are suitable for some home renovation or DIY projects, there is usually a choice to be made between the two.
OSB And plywood has unique characteristics, so it’s important that you choose the right one. Make the wrong choice, and you can iterate and fix much sooner than you should. Nobody wants that, and this guide will make sure you make the right choice.
How do OSB and plywood differ?
OSB and plywood are popular options for DIY projects and share similarities, but the main difference is how they are manufactured. At Mark Irving, Building Expert Build and plumbexplains. “OSB (oriented strand board) is an engineered wood panel made from compressed layers of wood strands bonded with adhesives.”
“Plywood, on the other hand, is a flat sheet of wood veneers glued together,” he continues, “with the grain of each layer rotated 90° relative to the previous layer.”
The difference in their make-up and construction is the main reason why you might choose one over the other for your DIY projects, as we’ll come to explain.
Mark has over 20 years of experience in the building sector, leading to a wealth of knowledge around building and renovation that he enjoys sharing with others looking to complete their own building projects.
How to choose between OSB and plywood
Martin Dooley, carpentry specialist and founder MD Carpentry WorkshopHere’s a quick summary of how to choose which board you need. “If the board is hidden and you need a strong, budget-friendly sheet, OSB is often a wise choice.
“However, if the board is going to be exposed, painted, stained or turned into furniture or shelves, plywood is usually worth the extra money because it’s easier to finish and looks better,” he advises.
“Start by asking if the board will be seen and what kind of wear it’s going to get, and the right choice usually becomes pretty obvious,” he adds.
Martin Dooley is a carpentry specialist and director of the MD Carpentry Workshop. With decades of experience, he specializes in all aspects of carpentry, from bespoke staircases to home renovations.
Buy tools and boards for your next DIY project
This marine plywood is ideal for high humidity areas. Made from hardwood veneers bonded with weather and boil proof (WBP) adhesive, each sheet measures 1220mm x 610mm x 12mm.
Einhell 50nm Cordless Drill
If plywood or OSB is used on a DIY project, you will often need to fix it to the frame. This daily exerciser has plenty of power and includes a charger and two batteries, so it’s ready to use.
Rigid and strong, this OSB measures 2.44m x 122cm x 9mm, making it a good choice for wall cladding over timber frames. Grade 3, making this board ok for wet conditions.
Advantages and disadvantages of OSB vs plywood
Understanding the strengths and weaknesses of each type of board can help you figure out which one is right for your intended use. Here we break down the pros and cons of OSB vs plywood using some key features:
1. Strength
Mark Irving notes, “The structure of the wood fibers in OSB gives it high strength and good load-bearing capacity along the length of the panel,” although plywood is just as strong. “The pattern creates nearly equal strength in all directions, because the crossing veneers in the plywood make it very rigid and able to span distances without sagging,” he notes.
That said, while OSB has high strength, it can struggle with improper handling. “The unprotected edge of OSB can be easily damaged,” Mark explains, especially during transport or installation.
2. Water resistance
“Modern adhesives make OSB highly resistant to delamination or deterioration when exposed to moisture for short periods of time,” says Mark Irving. “But, although it may be water resistant, it is not waterproof. Ideally, OSB should still be kept dry,” he notes.
“If the edges are exposed to too much moisture for too long they can swell,” adds Martin Dooley. This affects the integrity of the board.
Compared to OSB, plywood is less sensitive to moisture, but for more humid areas, marine plywood is better. Plywood is also prone to delamination, especially when exposed to excessive moisture; Which means it can start to fall apart.
3. Appearance
Martin Dooley says of OSB, “The downside is that it’s not the prettiest board in the world, because it has a rougher surface. It’s less suitable where appearance matters,” he adds.
While on the other hand, the smooth finish of plywood is a big plus. Higher grades have fewer natural defects, and there are also different wood finishes to choose from.
4. Weight
Knowing the weight of each item is also important as it can vary depending on where you want to use it and carry the board.
OSB is generally heavier than standard plywood, making it more difficult to transport and handle. As such, plywood may be more suitable if you need to move many boards upstairs for example in a loft conversion or bedroom.
5. Durability
In the sustainability stakes, OSB is generally considered the more eco-friendly of the two, as well as using smaller, faster-growing trees for its lumber, Mark Irving notes how, “OSB uses raw materials efficiently, produces less waste and can potentially incorporate recycled materials.”
Plywood, on the other hand, uses wood that depends on trees that take longer to mature than OSB.
Costs and sizes for OSB and plywood
As Mark Irving confirms, in terms of size and thickness, OSB is generally cheaper than plywood. “OSB is cheaper than plywood, and can cost 15% to 30% less for the same sheet size and thickness.
For example, this 2440mm x 1220mm x 12mm hardwood plywood from B&Q Currently £27. This comparative OSB3 board from B&Q Currently £22. A difference of about 20%, which can make a big difference on larger projects.
A common size for both OSB and plywood is 2440mm x 1220mm, although both are available in smaller sizes. In regards to thickness, Mark says, “OSB is available in sizes from 9mm to 40mm, with the thicker sizes typically made for heavy-duty uses and specialty applications. Plywood is typically available in thicknesses from 3mm to 25mm, with the thicker panels being better for structural applications.”
In addition to size and thickness, OSB and plywood are available in different grades. OSB is rated from 1 – 4, while plywood is graded from Class 1 – 3 for the performance of standard plywood. There is also marine plywood, which is bound to stricter standards and is more resistant to moisture.
OSB3 is generally a popular choice. Mark describes it as, “Load-bearing OSB for use in damp conditions.” Effectively, this means most DIY projects. Plywood is also classified based on appearance. AB plywood is the highest grade in terms of appearance, with CC grade being the lowest.
When purchasing OSB or plywood, check the grade and rating to make sure it meets the needs of your project. As a general rule, what you buy in hardware stores is fine for common DIY projects. However, if you need a specialist, be sure to check before you buy.
Where to use OSB?
OSB is a popular choice for many DIY projects where appearance is not important. This makes it a good choice for:
- Subflooring – OSB is a better choice for subflooring when building a timber frame for example. It is cheaper and more flexible, and can be covered with more aesthetically pleasing flooring.
- Wall and ceiling covering – Both OSB and plywood are acceptable, but Mark Irving recommends OSB. “OSB performs better if you use a moisture-resistant grade and avoid direct exposure to water.” For example, if Tiling on woodThat is, OSB, you need to add backer board like this Hardibaker backerboard from B&Q.
- Shade floor and ceiling – Martin Dooley says, “For sheds, I’d happily use OSB. It’s strong, practical and extremely cost-effective, especially for roofs and floors because no one can see it.” It is commonly used in Cheap shade.
If you are putting together a new shed using OSB, I recommend that you treat the exterior surface before you begin construction. A sealer like this Ceramico Coatings Liquid Rubber Roof Coating from Amazon Will help protect against moisture and extend the lifespan of your shade. Don’t forget to seal the edges too.
Where to use plywood?
Plywood is a popular choice for many DIY projects where appearance is important, and in some cases can be used as an alternative to OSB. This makes it ideal for:
- Furniture and shelving – Plywood’s smooth appearance makes it an ideal choice for furniture and shelving. “It can be practical and cost-effective when making furniture and can be used to make cabinet carcasses in kitchens and bedrooms,” says Mark Irving.
- walls and floors – It can be used for walls Wooden frame and exterior walls, as long as the right type of plywood is used. For subflooring, it can be an alternative to OSB. Ceilings that offer a natural look or painted finish are also choices.
- Bathrooms and kitchens – You can use plywood in high humidity areas if it is treated/sealed and covered, for example with tiles. Alternatively, you can use marine-grade plywood. However, marine plywood is more expensive than standard plywood.
If you’re using plywood for your DIY projects, you’ll need to know how to treat it to achieve the best finish. Our guides are ongoing Painting plywood And Waterproofing plywood will help prolong its life. Alternatively, you can use Plasterboard optional For interior finishes.
