Thorkil Schou was getting tired of his friends constantly asking what style house was being built on his Oakton land, so he gave it a label: Swedish Colonial.

"It's the only one, really," he said. The label seems to fit. after all, Schou is from Sweden, as is his house.

schou has taken the concept of do-it-yourself one step farther than most. He is the first known homeowner in the Washington area to design his own house, have it built by a Swedish factory and then shipped across the Atlantic to its present site, where it's about four weeks away from completion.

Having once worked for Sweden's largest developer, schou knew first-hand of his nation's reputation for factory-built quality homes with an emphasis on energy efficiency. As an architect and civil engineer, he also wanted to design his own house. Not being satisfied with American factory-built houses, and with the strong dollar on the European market, Schou decided to go with a Swedish firm.

"No, it's not for the average homeowner," he readily admitted.

Schou's odyssey began last March when his unassembled house arrived at the Baltimore harbor. After paying $6,000 in custom fees, Schou hired six trucks to deliver the contents of his house, which also had to be built with the Fairfax County housing code in mind.

Schou, who served as his own contractor, put the house together piece by piece, much like a jigsaw puzzle. Helping him were his wife, Lillemor, his three children, an American crew, specific directions from the Swedish factory and a crane. Preconstructed floors were laid down, then the walls. stuffed into two large crates were such components as windows, doors, kitchen cabinets and stairs. When emptied, the two crates were later laid into place to form two separate rooms, furthering the Swedish rule not to waste materials.

Schou said he is impressed with the home's features, especially its quality woodwork and features that should make it as energy-efficient as the average Swedish house.

The four-room home, totaling 4,000 square feet, cost nearly $400,000. The kit alone cost about $90,000. While the factory handled all the details for shipping, freight charges ran another $30,000. Construction and furnishings costs amounted to $270,000.

Because this was the Swedish factory's first house exported to the United States and the American crew lacked familiarity with the foreign-designed building-such as its use of the metric system-Schou said the project will take 11 months, twice as long as it should have. But because Schou wants to get into the business of importing Swedish homes someday, he figures his troubles were well worth it.

Although Schou's home construction efforts are unusual, the importation of quality-built homes from Sweden to the United States is becoming popular, especially in colder areas where energy-efficient homes can help most with heating bills.

Four years ago, only one Swedish company exported factory-built homes to the United States. Today, there are between 12 and 20 companies in the business, according to Toby Lander of the Swedish Trade Council in Chicago. With more than 150 companies making prefabricated houses in Sweden, it is inevitable that more firms will enter the U.S. market, Lander said. He added that, within a couple of years, these companies will end the expensive process of shipping their products, and instead open factories here using Swedish designs and technology.

Henry Kelly, executive director of the American Council for an Energy Efficient Economy, said that, although the Swedish builders won't ever be "a big chunk" of the market, he sees the American industry "already looking over its shoulder and saying, 'Hey, if we don't get our act together this could be a major problem.' "

Others agreed. Charles Graham, professor of architecture at Texas A&M University, who has done research on foreign companies entering the U.S. housing market, said, "The question is not if, but when" foreign competitors will invade the market. He said that besides the Swedish, the Japanese and the Danish also are beginning substantial housing projects in the United States. He added that he is concerned that, despite the trends he is witnessing, american builders are not taking any steps to counter the foreign competition. These foreign housing companies will bring quality products "that American buyers are not used to," he said.

Washington housing consultant Paul Kando said he sees the Swedish imports as "a catalyst" that eventually will eat into this country's prime housing market. As long as the dollar is sound, "They sell themselves," he added.

John Crowley, director of research and development for Ryan Homes in Pitrtsburgh, said that, while "the Swedes have found a market niche as Volvo and Saab have found (their) niche," he is not convinced the Swedes will have much of an impact on the American market.

Swedish Wooden Homes, the first Swedish firm to enter the market in 1981, employs "American engineers to meet U.S. codes, American architects to meet American tastes" and Sweden's building technology "to create the best of both possible worlds," according to its president, Seth Weinstein. His company has built homes throughout New England, in sizes ranging from 1,200 to 7,000 square feet, and priced from $100,000 to $1.5 million.

Aside from its own building projects, the company also sells houses to American builders. Two building projects are under way in Westchester County, N.Y., said Weinstein, who expects 1986 "to be the year when the volume of sales will take off." The company already has orders for 100 homes to be delivered next year to builders in New York and New Jersey.

Ric Guilbert, the company's architectural and planning chief, said that while his homes are highly energy efficient in keeping with Swedish tradition, such features are not the most important factor in selling his product. he added, however, that "the smart buyer is obviously looking toward the future."

One of the bigger Swedish housing projects in the United States is being built in the Boston area, where 220 houses and 345 condominiums are planned for completion in the next five years by Skanco Sharon-Foxboro Development Corp. Condominium prices have not been set, but the single-family homes are expected to average $245,000, according to the company's project manager, Lars Ersmarker. By next fall, the company hopes to be constructing three units each week.

Swedish designs, which traditionally mean smaller bedrooms, fewer baths, and less square feet than American homes, would not sell here, said the company's American architect, Ed Lyons. His new homes have kept Sweden's high-quality features, he said, but have been redesigned to be "stylistically appropriate to New England."

With the exception of the foundation, and the electrical and heating systems, the Skanco homes are entirely Swedish. The sides arrive with finished exterior walls, insulation in place, and windows and doors mounted. Only the interior walls are left unfinished to allow for installation of the electrical system.

Lyons, who said that the Swedish technological advances are "far superior" to anything he's seen in his 20 years in the industry, added that American builders have the capability to match their Swedish counterparts. "We just haven't," he said.

At least one American factory home builder has incorporated Swedish technology into his business. Brian Curran, President of Buffalo Homes in Butte, Mont., said he had been producing factory homes for about four years, but that he started using Swedish factory techniques because ''their technology was advanced over ours'' to secure more energy efficiency.

Curran, whose company is building 50 to 80 units a year in the $40,000 to $80,000 price range boasted that his business has been doubling every year with the aid of the foreign technology.

Curran's operation, with its practice of using an American-based factory to incorporate Swedish components, might reflect the future for the Swedish market, that way Swedish advancements could be brought to the U.S. market and costs could be lowered by eliminating expensive shipping and custom costs, according to some housing experts.

Because of the harsh Montana winters, an important feature of curran's homes is their energy-efficiency package, which includesf a three-year warranty that promises to pay the amount of a homeowner's heating bill that exceeds $100 a year.

Curran added that he'd like to see more Swedish technology here but American builders are standing in the way. American builders don't want to adapt because ''their Dads didn't do it that way,'' he said.