Mechanical Engineering Expert Allowed to Opine on Tile Flooring

This matter arises out of a slip and fall incident that occurred in the restroom at the Waffle House restaurant in Dillon, South Carolina. On January 3, 2020, Plaintiff Loretta Diaz entered the ladies’ restroom at the Defendants’ Waffle House location and traversed the restroom floor, when she slipped and fell on a foreign substance that had accumulated on the floor.

Plaintiff alleged in her complaint that the Defendants failed to maintain its property in a reasonably safe manner.

Plaintiff retained Dr. Bryan Durig to render an expert opinion as to the engineering of and the slip-resistance of the restroom floor. Defendants argued that Durig’s opinions in this case must be excluded because Durig performed a wet test of randomly selected tiles—rather than reading Plaintiff’s testimony about her slip and fall—and did not use the actual substance Plaintiff fell on for the test.

Mechanical Engineering Expert Witness

Dr. Bryan R. Durig is a registered professional engineer in the states of South Carolina and North Carolina, holds a Ph.D. in mechanical engineering, and is certified as a forensic slip expert by the National Institute of Forensic Studies.

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Discussion by the Court

In his report, Durig explained that he examined and tested the tile flooring in the ladies’ restroom of the Dillon Waffle House and that it failed to meet the minimum wet dynamic coefficient of friction required by industry standards to be considered slip resistant; thus, he opined that the flooring did not meet building codes or industry standards for a slip-resistant walking surface.

Defendants did not challenge Durig’s qualifications as an expert witness. Instead, Defendants contended that Durig’s testimony is irrelevant, immaterial, and unreliable under controlling South Carolina law because he tested the coefficient of friction of the restroom tiles only when they were wet rather than both when they were wet and when they were dry. They also argued that Durig’s opinion is unreliable because he was unfamiliar with Plaintiff’s deposition testimony, believed that the foreign substance Plaintiff slipped on was Coke rather than water, and did not know where in the ladies’ restroom Plaintiff slipped and fell.

Finally, Defendants asserted that Durig’s testing used a soap solution rather than water, that he presented no evidence to establish that the methodology used was peer-reviewed and scientifically approved, that he showed a lack of understanding regarding the tests and significance of the result numbers, and that he used a standard promulgated in 2022 for an accident that occurred in January 2020.

Analysis

The National Floor Safety Institute (“NFSI”) was designated as the standards developer for the ANSI in June 2006 to develop standards for safety requirements for slip, trip, and fall prevention, and ANSI approved the first NFSI standard in October 2009. 

Durig tested for the wet dynamic coefficient of friction of three flooring tiles in the ladies’ restroom of the Dillon Waffle House in accordance with the ANSI/NFSI B101.3 industry standard. Durig testified that he tested the wet dynamic coefficient of friction and did not test the floor in a dry condition because Plaintiff had stated she slipped on a liquid foreign substance.

As a result, the Court concluded that Durig’s opinion is based on a reliable methodology. Indeed, most of the issues Defendants raised to challenge Durig’s opinion and testimony are fodder for cross examination and did not render Durig’s opinion unreliable.

Held

The Court denied the Defendants’ motion to exclude the testimony of Bryan Durig.

Key Takeaway

The interests of justice favor leaving the difficult issues in the hands of the jury and relying on the safeguards of the adversary system—Durig’s testimony should be attacked by cross examination, contrary evidence, and attention to the burden of proof, not exclusion.

Case Details:

Case Caption:	Diaz V. Waffle House Inc.
Docket Number:	4:23cv45
Court Name:	United States District Court, South Carolina
Order Date:	January 09, 2026