Two home improvements stores are accused of deceiving the buyers of four-by-four boards, the big brother to the ubiquitous two-by-four.

The alleged deception: Menards and Home Depot (HD) market and sell the hefty lumber as four-by-fours without specifying that the boards actually measure 3½ inches by 3½ inches.

The lawsuits against the retailers would-be class actions, filed within five days of each other in federal court for the Northern District of Illinois. Attorneys from the same Chicago law firm represent the plaintiffs in both cases. Each suit seeks more than $5 million.

“Defendant has received significant profits from its false marketing and sale of its dimensional lumber products,” the action against Menards contends.

“Defendant’s representations as to the dimension of these products were false and misleading,” the suit against Home Depot alleges.

The retailers say the allegations are bogus. It is common knowledge and longstanding industry practice, they say, that names such as two-by-four or four-by-four do not describe the width and thickness of those pieces of lumber.

Rather, the retailers say, those are “nominal” designations accepted in government-approved industry standards, which also specify actual minimum dimensions — 1½ inches by 3½ inches for a two-by-four, for example, and 3½ inches by 3½ inches for a four-by-four.

“Anybody who’s in the trades or construction knows that,” said Tim Stich, a carpentry instructor at Milwaukee Area Technical College.

True enough, said Yevgeniy (Eugene) Turin of McGuire Law, the firm that represents the plaintiffs in both cases.

However, Turin and his clients dispute that the differences between nominal descriptions and actual dimensions are common knowledge.

“It’s difficult to say that for a reasonable consumer, when they walk into a store and they see a label that says four-by-four, that that’s simply — quote unquote — a trade name,” Turin said in an interview.

Turin said his clients don’t argue that the retailers’ four-by-fours (and, in the Menards’ case, a one-by-six board as well) are not the correct size under the standards published by the U.S. Department of Commerce. The product labels, however, should disclose that those are “nominal” designations and not actual sizes, Turin said.

With some of Menards’ lumber products, both the nominal and actual size are shown, a document Turin filed in the case against Menards says. But the lumber in question is labeled only with a nominal size — “4 x 4 — 10’,” for example — that consists of numbers “arranged in a way to represent the dimensions of the products,” the document says. That leaves the “average consumer” to conclude that the pieces measure four inches by four inches, Turin said.

Some Menards customers aren’t buying it.

“They haven’t measured four inches by four inches since the ‘50s,” said Scott Sunila after loading purchases into his pickup.

“My God, that’s crazy,” the 60-year-old bulldozer operator said of the lawsuits. “Let me on the jury. They ain’t winning. And they’re gonna pay me extra for my time.”

But an unscientific survey of 18 Menards shoppers found that about a third were unaware that “four-by-four” doesn’t represent actual dimensions of that piece of lumber.

Stich, the carpentry teacher, also said the average homeowner might not know about such distinctions between lumber names and dimensions. And Turin said comments on the Home Depot website show that “there are actual customers being confused.”