Oriented Strand Board, commonly referred to as OSB, has long been a popular material in the construction industry. However, the National Roofing Contractors Association (NRCA) has recently taken a clear stance against using OSB for roofing in steep-slope applications. This recommendation represents a commitment to higher quality and durability in roofing systems. Here, we’ll examine what OSB is, why the NRCA has flagged it as unsuitable for steep-slope roofs, and what this means for the roofing industry moving forward.
What Is OSB, and Why Is It Problematic for Roof Decking?
Understanding the implications of using OSB for roofing is crucial for contractors and building owners.
OSB is engineered wood composed of thin, rectangular wood strands bonded with wax and synthetic resins. It’s valued for being lightweight, relatively inexpensive, and easy to work with, making it a common choice for various building applications, including roofing, wall sheathing, and flooring.
However, when it comes to steep-slope roofing, OSB has a significant weakness: its vulnerability to moisture. If exposed to water for prolonged periods, OSB tends to swell, disintegrate, and rot. The damage isn’t merely a cosmetic problem. Once moisture compromises the integrity of the decking, it creates a domino effect. Other crucial roofing elements, such as shingles and underlayment, can fail due to a weakened base. Over time, this leads to costly repairs and reduced lifespan for the entire roofing system.
BEPG has been aware of these drawbacks from the beginning. We’ve never recommended using OSB for steep-slope roofs, and we’ve actively supported industry efforts to move toward more reliable and durable alternatives. The NRCA’s updated recommendation reinforces a standard we’ve long advocated for.
Why Does This Change Matter for the Roofing Industry?
The roofing industry can breathe a sigh of relief with this clear and decisive guidance from the NRCA. By formally opposing the use of OSB for steep-slope roofs, the organization raises the overall quality bar for roof construction. It powerfully conveys to builders and contractors that better materials are essential for creating long-lasting roofs.
Having a respected trade organization like the NRCA take this stance helps regulate the industry in a way that benefits contractors and homeowners. It also reduces confusion about what materials are suitable for roofing applications. While the upfront cost of alternatives like plywood or high-performance sheathing may be higher, these materials offer superior resistance to moisture and greater durability, making them a wise long-term investment.
OSB Is Still Widely Used in Building Envelope Applications
It’s important to note that OSB still has its place in construction. For example, wall cladding commonly uses OSB. However, unlike roofing, no equivalent organization like the NRCA provides formal guidance for these applications. With fewer guidelines, the wall cladding industry often operates like the Wild West—as long as a material meets the minimum building code requirements, it’s deemed acceptable.
The problem here lies in the building codes themselves. While building codes establish baseline expectations for safety and performance, they represent the lowest level of quality a structure can legally have, leaving room for improvement and an opportunity for more innovative materials and practices. Builders who aim for higher standards can set themselves apart by choosing alternatives to OSB even where it isn’t explicitly required.
Higher Costs, Higher Quality
Switching from OSB to alternatives like plywood or laminated veneer lumber may increase material costs. However, the trade-off is higher quality and better performance, leading to a more optimistic and forward-thinking approach. Durable materials reduce the risk of failure, which saves money in the long run by minimizing maintenance and repair needs, fostering a sense of long-term planning and investment.
Quality should never be sacrificed for cost savings. That’s why we’ve always supported the use of materials that go beyond basic building codes. Though this shift will initially increase the price, it also represents progress toward more reliable, higher-performing structures.
A Step Forward for the Industry
The NRCA’s recommendation against using OSB for steep-slope roof decking is more than just a technical adjustment; it’s a commitment to better roofing standards. By steering the industry away from moisture-prone materials, the NRCA is helping contractors and homeowners invest in longer-lasting, higher-quality roofs. This progress should make everyone in the industry feel proud and motivated to strive for better standards.
Looking to the future, we encourage contractors and builders to take this momentum further. By applying the same diligence and quality-first mindset to other applications, we can continue to push the boundaries of what’s possible in construction. After all, building codes may represent the minimum, but there’s no limit to how much better we can aim.