LP® TopNotch® 350 Durable Sub-Flooring

Elevate your sub-flooring with LP® TopNotch® 350 Durable Sub-Flooring. Available in two options to fit any building project, our line of performance OSB sub-flooring helps you take your build to the next level.

Product Benefits


Incredible strength, stiffness and moisture resistance.

Easy Installation

Self-spacing tongue and groove design speeds installation.


Designed for optimum moisture resistance.


Wood sourced through programs certified under the Sustainable Forestry Initiative®.

RainChannel® Technology

Unique RainChannel notch system to help drain rainwater away during construction.

Product Specifications

  • Available performance categories from 19/32 to 1-1/8*
  • Can be used for residential and light commercial applications
  • LP TopNotch Sub-Flooring panels are certified by the APA – The Engineered Wood Association and are manufactured in conformance with U.S. Voluntary Product Standard PS2.
  • Additional information may be found in specific LP product literature and in literature from the APA, whose stamp of quality assurance appears on rated LP OSB products. You may contact LP at 1-888-820-0325 (Toll Free). The APA publications desk number is (253) 565-6600 and their extensive literature is available at
  • Consider our other OSB specialty sheathing products designed for wall applications (LP OSB Sheathing, LP LongLength and LP LongLength XL) and roof applications (LP TechShield Radiant Barrier Sheathing).

*Performance category replaces the fractional nominal thickness used in PS2. The Performance Category is consistent with the panel thickness used in the U.S. model building codes.


water on board

How It's Made

LP® TopNotch® 350 Sub-Flooring is manufactured by the leader in strand technology for a flat, strong and sturdy floor.

  • Rectangular wood strands blended with thermal-set, waterproof adhesives are arranged in cross-directional layers and bonded together under extreme pressure.
  • Notches cut into the panels contribute to RainChannel® technology.
  • LP TopNotch 350 Sub-Flooring product panels are surface sanded.
  • Moisture-resistant edge sealant is applied to all LP TopNotch products.

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