Despite its uninspiring name and haphazard appearance, there is much more to OSB than meets the eye. It is in fact a versatile timber-based board suitable for a wide range of DIY and home renovation projects.
It's commonly used as an alternative to plywood and, in some cases, as a plasterboard alternative, adding an industrial aesthetic to interior design projects. While it could be argued that it's less visually appealing, its composition still makes it a very attractive option for many DIY builds where aesthetics aren’t the number one priority.
Here, we delve into where it can be used, its benefits and drawbacks, and how much you can expect to pay.
What does OSB stand for?
OSB stands for Oriented Strand Board. Paul Kerr, building specialist at Beatsons, explains its makeup. “It's basically a wood panel made by heat pressing wood strands with glue.”
Mark Irving, building expert at Build & Plumb, explains what makes it appropriate for use in a variety of DIY projects. “The boards are strong and durable, which means they are commonly used for construction projects.”
Shop OSB board and tools to protect it
This 18mm thick OSB board comes in sheets measuring 2440mm x 1220mm, making it ideal for floors and walls. It is free of natural defects and is moisture-resistant
A quick-drying sealer that works on most types of wood, including MDF and OSB. The sealer goes on milky white, so you can see where you’ve painted, but it dries clear
This brush and roller set is ideal for sealing and painting. It includes a 9-inch roller tray, 3 medium-pile roller sleeves, and 1-inch and 2-inch brushes
Paul Kerr is a building specialist at Beatsons Building Supplies Limited, where he advises homeowners and trade professionals on durable, practical solutions for home renovation.
Mark has over 20 years of experience in the building sector, leading to a wealth of knowledge surrounding building and renovating that he enjoys sharing with others who are looking to complete their own building projects.
Popular uses for OSB
OSB is a popular choice for a lot of DIY and home renovation projects, but it's typically used inside the home explains Mark Irving. “OSB is most commonly used in internal construction projects, as it is incredibly strong and durable. Typically, it will be used for wall sheathing, roofing, loft boarding and site hoarding.
“OSB can also be used for subfloors, partition walls, and shelving" he adds, "as it provides a solid, stable surface.”
OSB is rarely used for work outside the home notes Paul Kerr, “as the boards are usually not weatherproof, and unless treated specifically, should not be used for external projects.”
If however the boards are protected or treated, they can be used on a range of projects, continues Mark. “OSB can be suitable for large-scale building projects such as timber-frame construction, sheds and DIY renovations.”
And, while it's often covered over, it can also be left exposed says Paul. “You sometimes see the odd interior design project using OSB for rustic shelving and tables,” he agrees. It’s also sometimes left bare on walls to create a more industrial aesthetic.
Pros and cons of OSB
Mark Irving reveals the key benefits and drawbacks of OSB:
Pros
- COST-EFFECTIVE: It is typically cheaper than plywood yet offers the same structural strength, making it the most popular choice for large construction projects where budgeting is crucial.
- DURABILITY: Because the wood strands are layered in different directions, OSB offers exceptional load-bearing strength, making it ideal for flooring and roofing.
- CONSISTENCY: OSB panels are typically manufactured in consistent sizes and densities to reduce weak spots and voids often found in timber projects.
Cons
- VULNERABLE TO MOISTURE: Standard, untreated OSB can often swell or deteriorate if exposed to moisture and water, particularly around panel edges.
- APPEARANCE: While it is incredibly practical, OSB has a rougher, more industrial appearance than standard timber or plywood, so it is often not a great choice for decorative applications.
- HEAVY: OSB is typically much heavier than standard plywood, meaning transportation and handling can be more difficult.
What sizes does it come in and how much does OSB cost?
As well as its strength and durability, there’s another reason why it's so attractive for DIYers and that's the cost. However, the price is determined by several factors, including size, thickness, and grade.
“OSB is one of the more affordable options for construction, with prices ranging between £15 and £35 per sheet,” says Mark Irving.
“The industry standard is 2400mm x 1200mm, and the thickness varies from 9mm up to 18mm," expands Paul Kerr. “The thinnest OSBs usually start from around £10, and usually don't sell for more than £25.”
As an example of price, this OSB 3 OSB 2440mm x 1220mm x 9mm from B&Q sells for just under £20. The smallest size sells for around £11. This 18mm OSB 3 OSB 2440mm x 1220mm x 18mm from B&Q sells for £24.
The cost of OSB is also why it's considered an attractive alternative to plywood in certain situations, continues Mark.
“Typically, OSB is cheaper, which makes it the ideal choice for structural applications where the appearance of the project is less important than the budget or the performance.“
“It's usually about 20% cheaper than a plywood board," adds Paul, "which is the reason why it's taken over as the most popular board for internal framing work.”
FAQs
Should I use nails or screws to fit OSB?
Both nails and screws can be used to install OSB. Which one you use can depend on the project. If installing OSB on internal walls, ceilings, and floors, screws are a popular choice because they are much easier to remove if you need to replace any OSB. Screws will also pull OSB tight against any frame and hold well.
These Single Thread Countersunk Pozi Screws from Toolstation will do the job. The screw length should be approximately twice the OSB thickness. If you are using 18mm OSB, 40mm or 60mm screws will suffice.
Nails are quicker to install, especially with a nail gun, and are often used for fixing to exterior framing as they offer more give.
If using nails, galvanised or stainless-steel ring-shank nails are recommended. Galvanised nails such as these Tacwise Extra Galvanised Framing Nails from Amazon are good for general DIY projects, as long as they aren’t regularly exposed to moisture.
Can I paint or tile directly onto OSB?
Yes to painting, no to tiling.
OSB is porous, which means it absorbs a lot of liquid. If you are going to paint OSB, you will need to start with a primer/sealer, such as this Zinsser B-I-N from Screwfix, to seal the surface and create a stable base for subsequent coats of paint.
When it comes to tiling, it's important to know that the board will absorb the moisture if you apply the tile adhesive directly to the board, causing it to fail. Tiles can fall off walls or start to shift and crack. However, it can be used as a substrate for tiles, provided you install a cement backer board (such as this HardieBacker 6mm Backerboard from B&Q) over the OSB.
You’ll also need to make sure that the OSB is secure and doesn’t flex. This is more applicable to floors than walls or ceilings. If it does, you’ll end up with adhesion issues.
How long does OSB last?
It depends very much on its usage. If installed correctly and protected, e.g., with wall sheathing, it can last for 20+ years. However, if left unprotected and exposed, it will depend on the environment. Internally, it can last for years, as long as it is not exposed to moisture.
If used externally and left exposed to the elements, OSB will be lucky to last a year. However, if well protected, with a sealant such as Siramico Coatings Liquid Rubber Roof Coating from Amazon, it can easily last five years. To extend its lifespan, make sure to seal the edges and reapply any sealant/paint every 3-5 years.
OSB is a multi-talented board; not only can it be used on its own, but it is also part of SIPs (structural insulated panels), which are a popular product for building extensions and homes.
