Maybe it’s the lack of frills, the run-of-the-mill shape, the austere lines. Or maybe it’s simply the sheer number of the low-slung houses, blanketing the suburban landscape like hardy ground cover.

But something about ramblers often stirs surprise and even skepticism when preservationists string them together with the word “historic.”

As more ramblers pass the half-century mark, Minnesota historians want residents to know that their simple floor plans and Pepto Bismol-pink bathrooms have an important story to tell. Largely built in the decades following World War II, their age now makes them potentially eligible for the National Register of Historic Places.

“People that own those homes don’t typically think of them as historic … because they are not necessarily architecturally unique,” said Ginny Way, a National Register architectural historian in the State Historic Preservation Office. Still, she added, “it’s hard to deny the importance of the largest building boom in U.S. history.”

Some Twin Cities suburbs have been working in recent years to raise the profile of the no-nonsense rambler with presentations, grant or loan programs for home remodeling and advice on how to renovate them with history and preservation in mind.

Coon Rapids has held programs on the building quality of the suburb’s famed Orrin Thompson homes, which popped up on pastureland in the 1950s and ’60s.

And in Fridley, a new historic home and garden tour Sunday will call attention to the historic value of ramblers and why they remain appealing to current and prospective homeowners.

Unlike owners of Twin Cities bungalows or other housing types, few rambler owners have so far expressed interest in listing on the National Register, Way said, despite clearing the 50-year guideline for inclusion.

That may partly stem from a lack of awareness, preservationists say.

It can be tough, after all, to value the history you’ve lived through, said Rebecca Ebnet-Mavencamp, executive director of the Anoka County Historical Society.

“They are not these big, castle­-like structures,” she said. “They are modest homes that were built postwar and served a very distinct, utilitarian purpose.”

Growing cachet

Ramblers largely rose on the landscape as GIs returned home after World War II. Acres of farmland and pasture turned into subdivisions with neat rows of tract houses roosting on broad green lawns. Ramblers often dominated the curvy streets and cul-de-sacs.

“They were built as starter homes,” Way said. “They continue to serve that function, and they serve it well.”

Many home buyers priced out of neighborhoods in the urban core are setting their sights on inner-ring suburbs and scooping up ramblers, local real estate agents say. Ranch-style houses dot some of the hottest housing markets in the Twin Cities, from Richfield to Fridley to Crystal.

Ramblers are one of “very few houses out there” near a starter house price, sometimes selling for about $250,000, said Betty Hardle, who has been in the homebuilding business for nearly five decades and is president of Residential Research Services in Columbia Heights.

“There’s a shortage of them on the market,” Hardle said. “As soon as they come on the market, they’re pretty much bought within a week.”

But even these simple houses have seen prices rise, thanks in large part to their locations, said Brad Fox of Fox Homes, a Minnetonka-based real estate brokerage that also specializes in home renovations in the Twin Cities.

Fox said some buyers are drawn from boxy urban bungalows to inner-ring suburbs in their hunt for a bit more space and the one-level bedrooms that ramblers offer. With midcentury aesthetics enjoying new cachet, Fox has even seen some residents wanting to keep their pink-tiled bathrooms intact.

Plus, a rambler’s rectangular design makes it easy to dress up, he said: “The things that make them simple and clean are also what give them the most amount of potential.”

Often free of mold and leaky roofs, the houses defy the ticky-tacky image of popular culture, with real estate agents praising their rock-solid construction. Slowly, ownership is changing hands.

“We are starting to finally get some turnover from those original owners,” said Coon Rapids Mayor Jerry Koch, a real estate agent.

‘Ramble back in time’

In Fridley, the ramblers dotting the landscape recall the suburb’s most famous era: the 1960s. Many houses still standing tell of tremendous postwar growth — along with those knocked down by monster tornadoes.

A 1965 tornado outbreak remains etched in the city’s collective memory and into the very walls of area houses, including 82-year-old Warren Olson’s rambler near Rice Creek. The Olson family rode out the storm in the basement of their 1961 home.

People will be able to glimpse Olson’s home in Fridley’s home and garden tour from 1 to 5 p.m. Sunday, anchored by the theme “Ramble back in time.”

Olson, a retired teacher and coach, is his rambler’s original owner. As young parents, Olson said, he and his wife Sandy made a beeline for the house with big trees.

“We bought it 20 minutes after he put the for-sale sign up,” Olson said. “When you stay in one place long enough, it becomes history.”