Backed by Science: University of Maine Puts Sub-Flooring to the Test

November 1, 2019
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All sub-flooring panels undergo some measure of product testing before they’re introduced to the industry. A few panels go even further.

LP Building Solutions has been putting its LP Legacy® premium sub-flooring panels through rigorous, sometimes extreme, testing far beyond industry standards since the product was introduced to the market. Those efforts continued at the University of Maine’s Advanced Structures and Composites Center, where wood scientists put the LP Legacy panels, along with plywood and commodity OSB, through seven months of rigorous testing to determine real-world performance. Unlike lab tests for strength and stiffness that might last an hour, the university’s study took place in four phases and lasted over 14 months including a conditioning period to truly emulate the conditions builders and homeowners see in the real world. 

The university’s study consisted of four phases:

Phase 1:

Fastener holding capacity tested by creating small-scale floors of oak hardwood flooring stapled to the sub-floor and pulled off with a specially designed test jig. LP Legacy offered a 35% higher withdrawal capacity compared to the other two subjects.

LP University of Maine Sub-Flooring
For Phase 1, testers attached the sub-floor panels to hardwood flooring and forced them apart on a jig to gauge fastener-holding capacity.

Phase 2:

Testers subjected the panels to a simulated rainstorm for eight hours, brought the panels back down to their original moisture content for 48 hours, and then repeated the process two more times. LP Legacy took two-and-a-half times longer to absorb the moisture compared to the other two products, and once again had the highest fastener holding capacity. 

Phase 3:

Testers simulated seasonal moisture variations that exist in most homes by taking the samples from the Phase 2 wetting cycle, attaching hardwood flooring, and cycling between moisture extremes in a conditioning chamber. After nearly a year, the LP Legacy sub-flooring panels had no significant dimensional changes. 

LP University of Maine Sub-Flooring
Panel subjects were placed in the conditioning chamber for nearly a year.

Phase 4: 

Finally, the panels underwent a 50,000-footstep load simulation. Testers looked for floor squeaks, as well as the withdrawal capacity of fasteners after all of the exposures. After four phases of testing, the fastener capacity of LP Legacy remained virtually unchanged. 

LP University of Maine Sub-Flooring
In Phase 4, a machine simulated walking on the panels 50,000 times.

“After all of the exposures, the repeated wetting, the repeated hydrothermal cycling, and the repeated loading, the fastener capacity of Legacy sub-floor has virtually remained unchanged,” reported Benjamin Herzog, a Wood Technologist for the University of Maine who was conducting the tests. 

The tests add to the many others LP has conducted over the past several years to push LP Legacy to help builders see how it will perform under jobsite conditions (and then some); the simulations are in addition to, and often have gone far beyond, tests required by the industry or offered by APA-The Engineered Wood Association. LP’s protocols included a “Tested Extreme” campaign, which saw Legacy panels sent over a waterfall, converted into muddy mountain bike ramps, and submerged as a shark cage. 

Made with Gorilla Glue Technology®, LP Legacy sub-flooring is the stiffest in its class and one of the industry’s strongest panels. The panel’s stiffness makes it ideal for hardwood flooring and tile applications, and high panel density provides exceptional fastener holding strength and a quieter floor. And with superior moisture resistance, LP Legacy sub-floor panels carry a Covered Until It’s Covered® no-sand warranty.

To learn more about the University of Maine testing and hear from the scientists conducting the study, watch this video.

Note: The views expressed by University of Maine staff should not in any way be considered to be, and do not constitute or imply, the endorsement, recommendation, or favoring of any particular product.

Senior National Product Manager for OSB and EWP

Kelly Harmon is the Senior National Product Manager for OSB and EWP for LP Building Solutions. He is one of LP's most experienced industry and product experts, having spent almost twenty years in sales, marketing and management roles for leading building products manufacturers.

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