Experts weigh in on the use of OSB

The latest 2019 NWFA Guidelines define high-performance oriented strand board (OSB) as: “OSB products that have obtained a third-party evaluation documenting greater strength and stiffness compared to either plywood or commodity OSB by virtue of their engineered design and makeup.”

To learn more about these products and how they may be used, we asked experts with Huber Engineered Woods, Louisiana Pacific (LP) Building Solutions, and Weyerhaeuser their thoughts on this category.

What advantages do you see with high-performance OSB products being used in home construction today?

Kelly Harmon, Senior National Product Manager for OSB and EWP for LP Building Solutions: In today’s construction, with larger and more complicated homes, the cycle to get these homes to a “dried- in” state is taking longer. That means more exposure to the elements, which can compromise the performance of some products used for the structural frame. Not only reducing performance, but also shortening the life of these products due to delamination, flaking, swelling, and lateral movement. This is the main reason that more and more builders are using a high performance OSB. This high-performance OSB will help resist the performance issues you could encounter with commodity OSB. In addition to protecting the floor while being exposed to the elements during construction, it also provides phenomenal nail/staple retention values due to the high density of wood strands, MDI resins, and waxes. This helps in the consistent performance that you will need when dealing with hardwood flooring.

Alex Kuchar, OSB Technical Manager for Weyerhaeuser: High performance OSB absorbs less moisture, is more durable, and is easier to install. With more demanding floor finishes like hardwood and engineered wood flooring, a high performing panel will absorb less moisture when compared to the commodity OSB. These flooring products improve durability, and performance on the job site.

Mike Pyle, Director of Technical Services for Huber Engineered Woods: High-performance subflooring panels typically have strength, stiffness, and fastener holding power that surpass commodity offerings and are validated in a published evaluation report by an accredited third-party agency. These physical properties directly influence the overall performance of hardwood floors, especially deflection. A lot of attention is paid to fastener holding power, which is important, but the bigger influencer of performance is subfloor stiffness. Squeaks from staples or cleats occur when a fastener can no longer bear the stress a sagging or bouncy subfloor puts on the fastener. The more you control the deflection of the subfloor, the less stress is transferred to the hardwood flooring fastener and the risk for squeaks is lessened. Diagnosing and fixing squeaky hardwood flooring can be costly in terms of time, dollars, and reputation. High-performing OSB subfloors deflect less and hold hardwood flooring fasteners better than commodity OSB, which results in lower risk of squeaky floors and unhappy homeowners.

What are the benefits?

Harmon: Exceptional fastener holding and the resin technologies used in these products provide exceptional strength, stiffness, and moisture resistance qualities that allow manufacturers to provide provide exceptional warranties.

Kuchar: The homeowner can feel the solid floor stiffness when they walk into a home. Having a higher performing OSB will give you less deflection, when compared to a commodity OSB, which translates to a ‘solid’ floor that consumers can feel. For the builder, high-performance OSB will absorb less water compared to commodity OSB. The builder will experience less panel swelling, which will shorten the dry out time. The lower moisture absorption will also lead to a better fastener performance when the finished floor is nailed to the subfloor.

Pyle: A few standout benefits of high-performance engineered panels are the reduced risk of squeaky floors and, overall, a better feel underfoot. This results in the ultimate benefit – happy homeowners and fewer callbacks.

How do these products affect the builder who implements a moisture management plan during the construction of the building?

Harmon: For builders who want high performance products that help mitigate issues with water and/or moisture, high-performance OSB used for subflooring provides that needed element to ensure the floors of the home will not have reoccurring issues and perform for a quieter floor to foot traffic. After all, most of the call-backs, floor performance issues, and headaches come from the subfloor that gets exposed to the elements during construction. So why not use a high-performance product to help minimize these issues?

Kuchar: Using a high performing OSB can lead to reduced call backs. Since they absorb less water and dry out faster, it can also mean a faster building cycle, which will save the builder time a nd money.

Pyle: The moisture relationship between hardwood floors and the subflooring is critical for quality performance and appearance for both the short- and long-term. Commodity OSB has a reputation for swelling and losing strength when it is exposed to rain during construction. Similarly, ply wood is known for not staying flat and for delaminating when exposed to a lot of wet weather. Builders have to think and plan how the products they choose will withstand the rigors that the construction process puts on them and if they can withstand the abuse. High-performance OSB subfloors are moisture resistant and durable enough to withstand the construction process. They typically have lower water absorption rates, which means they take in less water when rained on during the construction process. Less rain in the panel results in less water that has to dry out before hardwoods can be installed, which lowers the risk of problems in the hardwood flooring installation.

How should moisture testing be conducted on high-performance OSB?

Harmon: When measuring the moisture content of our single-layer structural subflooring in the field, either a hand-held pin-type or pinless meter should be used. The pin-type measures electrical resistance between the two pins that are pressed into the subfloor, and the pinless meter is laid atop the surface of the panel and uses the principle of electrical impedance to measure moisture content.

Kuchar: For testing moisture content of our products in the field, a pin-type moisture meter should be used.

Pyle: Use a pin-type moisture meter for measuring the moisture content of our subflooring panels. In order to get the most accurate reading, the user just needs to ensure it is set to the correct species setting. Most come with an OSB setting.These high-performance subfloors are being used in more new construction buildings today than ever before. Be sure to understand the subfloor you are installing over to adequately prepare it for wood flooring installation.

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