Best Options for Sub-Flooring: LP Legacy® vs. LP® TopNotch® 350

Choosing durable sub-flooring for your projects is crucial to a strong structure and successful build, but finding the right fit for your projects among a variety of commodity and premium product offerings can be overwhelming. LP offers two high-performance sub-floor material options at differing price points to suit a variety of needs.

We spoke with Jeff Jayne, OSB/EWP Process Product Development Manager at LP, to break down each product and help you discover the best options for sub-flooring for your next build. 

What is LP® TopNotch® 350 Sub-Flooring?

LP TopNotch 350 Sub-Flooring is a high performance OSB product aimed to help reduce the impact of moisture and add strength to residential and light commercial builds. It is trusted by builders looking for a stable, solid structure that boasts moisture resistance at a great price point. 

“With LP TopNotch 350 Sub-Flooring, you get enhanced moisture-resistant properties and uniform thickness—two areas of value add,” says Jayne. 

LP TopNotch 350 panels feature unique RainChannel® technology to help drain water away during construction. The self-draining notch system allows water to drain quickly from the surface and helps minimize swelling. Combined with a moisture-resistant edge seal the RainChannel system helps fight moisture absorption and edge swell, reducing the need for sanding.

What is LP Legacy® Premium Sub-Flooring?

LP Legacy Premium Sub-Flooring is a strand-based composite wood panel designed for demanding sub-floor applications. The product is proven tough and APA-verified for exceptional stiffness and strength. It’s LP’s most premium sub-floor material. 

“LP Legacy panels bring a handful of values to the table—first and foremost, stiffness and strength,” says Jayne. “Stiffness directly translates to deflection so the consumer will see a noticeable difference in the way it feels under their feet compared to other products. While strength isn’t as physically noticeable, it gives consumers peace of mind and comes into play in heavier loads such as pianos and large appliances.” 

Wood strands used to make LP Legacy sub-flooring are coated with a water-resistant adhesive that uses Gorilla Glue Technology® for added stiffness and moisture resistance. For further protection, the edges on each board have a clear high-performance edge seal.

LP Legacy panels are also known for high density for exceptional fastener holding which, combined with high stiffness, results in a superior sub-floor to support high-end floor coverings like hardwood and tile.

Curious about just how stiff it is? Here are the stats:

• Bending Stiffness: Parallel Direction (Nominal 8´) – 395,120

• Bending Stiffness: Perpendicular Direction Nominal (4´) – 160,980

• Bending Strength: Parallel Direction Nominal (8´) – 1,300

• Bending Strength: Perpendicular Direction Nominal (4´) – 750

• Panel Weight Southern species: 82 lbs; Northern species: 76 lbs

What is the Best Material for Sub-Flooring?

LP TopNotch 350 Sub-Flooring boasts moisture resistance and durability at a great price point, while LP Legacy panels offer greater stiffness and strength in addition to moisture resistance for higher demand builds.

As you plan for your next build, consider what the structure will be used for. Is it residential? Commercial? Will there be heavy furniture or foot traffic? 

Refer to the product summaries below to inform your decision as you answer those questions.

LP TopNotch 350 Sub-Flooring

• Best value in durable sub-flooring

• Moisture resistant

• Sanded for uniform thickness 

• Backed by a 200-day “no-sand” warranty and a 50-year transferable limited warranty

LP Legacy Premium Sub-Flooring

• Proven to be one of the stiffest sub-floors on the planet 

• Higher moisture resistance due to resins made with Gorilla Glue Technology®

• Sanded for uniform thickness

• Covered Until It’s Covered® no-sand warranty—plus a lifetime limited warranty that lasts as long as the structure

As you weigh your sub-floor material options, remember that even for a single home or commercial structure you aren’t tied to using one product. Many projects will allow for use of both LP Legacy and LP TopNotch 350 panels depending on an area’s level of exposure to the elements, weight bearing capacity and budget. 

“During construction, the second level of a build may be exposed to the elements for a longer period of time,” says Jayne. “In that case, opt for a more premium product such as LP Legacy Premium Sub-Flooring for maximum protection.”

In addition to exposure, the serviceability of an area will also determine where to use certain sub-flooring. Structures such as apartments that have a storage area on one level and living spaces on other levels can utilize a combination of the two sub-flooring products. Jayne suggests using LP TopNotch 350 panels for regularly trafficked living spaces and LP Legacy panels for areas that will bear more weight. 

LP also offers LP Legacy® Premium Sub-Floor Adhesive, designed to be used either with LP Legacy panels or LP TopNotch 350 panels. This adhesive protects against squeaks by expanding to create a tight seal in small gaps between panels and supports. No matter the sub-flooring project you choose from LP, you can boost its effectiveness with a high-performance adhesive. Read more about it here.

Interested in learning more about sub-flooring from LP? Check out warranties and installation instructions for LP TopNotch 350 Sub-Flooring here and learn more about LP Legacy Premium Sub-Flooring here.