Americans' growing fears about the economy and foreign crises are producing a mini-boom in "survival" real estate.

Small firms of architects, builders and real estate promoters are beginning to specialize in doomsday properties -- new and remodeled homes that can survive civil unrest and extended breakdowns of public services and food supplies. They don't look different in any way from neighboring houses.

The properties contain everything from independent power-generating systems to reinforced concrete food storage and radiation shelters, steel doors, sophisticates security sensors and weapons, water wells and pumps. Their locations range from quiet suburban neighborhoods outside major northeastern and West Coast cities to rural retreats in the Rockies, the South and near ocean resorts.

Costs go from $20,000 and up for "security" remodelings to $65,000 and up for newly constructed homes.

Some of the properties are even being marketed as multi-purpose tax shelters -- rental investment homes during normal years, bomb shelters and survival refuges during times of national crisis.

Joel Skousen, president of Survival Homes Corp. of Hood River, Ore., has eight full-time architects who have worked on projects in 30 states in the past 10 months. He says the trend is "far more pervasive and long-term in the United States than most people would care to believe or talk about."

Executives in suburbs in the Midwest or the East "don't go out and tell all their neighbors that they've just installed a security shelter equipped with food, tools and emergency supplies in the cellar of their brick colonial," Skousen observed.

Nor do lawyers, engineers and businessmen in the South and West necessarily tell their neighbors that the "second home" they've just built in the mountains has independent power-generating equipment, food stocks and other survival gear.

"It's like the bomb shelter issue in the 1950's," Skousen said. "You don't want your neighbors to think you might lock them out."

An East Coast developer who's actively involved in the trend is selling survival homes to what he considers a "mass market." These are families who live within five hours of the Maryland-Delaware seashore who can afford the monthly payments on a $65,000 to $89,000 second home.

Robert Firth, vice president of Firth Realty in Ocean Pines, Md., equips his subdivision homes with "everything you'd need to exist indefinitely if public services and normal food supplies were cut off."

This includes a propane-fueled, five-kilowatt electric generator adequate to run appliances for weeks and a radiation-resistant concrete cellar -- sealed off by steel doors -- containing one year's food supply. It also includes 1,000 rounds of ammunition, rifle and shotgun; a 250-gallon propane tank, an indoor water well and cistern, a $2,800 fiber glass skiff with outboard motor and a custom set of tools and farm implements.

Other features: a wood-burning, high-efficiency furnance with hot water coils, silent alarm systems, flares, extensive medical supplies, a library of survival and self-sufficiency books.

Located in a land development near Ocean City, Md., Firth's homes look like others in the area and are selling briskly, despite the financing squeeze. With virtually no advertising, Firth says he has sold or completed 10 semi-custom survival retreats in the past eight weeks alone.

Firth's building company got into the survival field after he read Howard Ruff's best-selling book, "How to Prosper During the Coming Bad Years." Firth says he doesn't subscribe to all of Ruff's forecasts of gloom and doom, but thinks "there's enough to be concerned about to justify a little preparation for the worst possibilities."

For city-based buyers who are interested in renting out their survival unit, Firth has even prepared cash-flow, depreciation and tax-shelter projections. The units lease for $350 to $400 a month year-round, and can generate $5,000 to $6,000 in deductions the first year, by his reckoning.

"Why not use the federal taxes system to help pay for your own survival, or your tenants?" Firth asks. "It's a concept that a lot of people are taking seriously than you think!"