Long before the recent trend to building small enclaves of housing in the District began, Barrett M. Linde was doing it successfully on Capitol hill - and any other place he could convince owners of the right pieces of ground to come in with him as partners.

In 18 years, the 40-year-old builder has completed more than 30 projects, about equally divided between sale and rental housing. Altogether he has built some 400 dwellings.

After graduating from Harvard and undertaking graduate work at the University of Pennsylvania's Wharton School nights while working days for a realty firm. Then he started building.

"I guess studying law got to be too much - and besides, I really like doing physical things, such as building or sports, rather than being sedentary," he said the other day as he made the rounds of some of his projects.

These include 28 one-bedroom apartments behind a town house faced in the 1700 block of Q Street NW and a group of rental apartments in a traditional town house design on a small site at 16th and Irving streets NW. Both were designed by Edmud W, Dreyfuss & Associates.

Also under way are 51 one-bedroom of Corcoran Street NW, a site purchased recently for $660,000 by Management & Development Associates, Inc., and Linde. (This site was picketed some years back by neighborhood preservationists when another prospective buyer planned a high-rise for the site.)

In January, Linde plans to begin building in the Palisades area at McArthur Boulevard and Arizona Avenue NW, using designs for 25 town houses and three detach houses drawn up by the Patterson & Worland architectural team.

Newly completed are 19 rental units inside a town house configuration at 19th Street and Florida Avenue NW. Other Linde rental units have been conmpleted recently in the area of 18th, 19th, Swann and T Streets NW.

In reviewing his track record, Linde says he has exposed the role of the small developer-builder to maintain control of his projects.

"But I'd have say that my motivation, other than for reasonable financial success, has been to be a part of this city, where my family has lived for several generations," he said.

"Expect for the Westbard Mews town houses in Bethesda and Pommander Walk town houses in Old Town Alexandria, my other small developments have been in the District - many in Southeast and Northwest and one in Noetheast. We like to think that what we have built has contributed to raising the residential level of the areas. That's been the goal and our product acceptance indicates success."

When he says "we," Linde refers to a relatively small organization. In addition to a secretary and a bookkeeper, he has one general superintendent, Don Carle, and three young "supers." The latter handle jobs on the sites.

Some of the men have had some college education and some started as laborers. Carle was a carpenter when he joined Linde more than 10 years ago. The job superintendents, Doug Miles, Kirt Barbee and John Paton> work on a bonus-incentive basis, part of the Linde to delegate responsibility without relinquishing his own day-to-day direction.

Linde has gained a reputation as an intown innovator. He copied Capitol Hill's traditional English basements (separate rental units) when he built in that neighborhood, and later included them in town houses he built elsewhere in the city. This type of construction enables the owner of a two-level town house to have a first-floor rental unit or separate apartment for a family member.

The layout has been carried over to the developments where Linde rents rather than sells units. His complex of town house renatl units of Lanier Place NW, for instance, have English basement apartments that rent for $315 a month with two-level units above that rent for more than $500.

Currently, Linde and his superintendents have been finding satisfaction in a new design - one-bedroom condominuim dwelling called Dupont Row on the north side of Q Street NW, near 18th. Designed by William Henry of the Dreyfuss architectural staff, the town house-like dewlling include three separate units on four levels.

The lower, one-floor dwelling is a few steps below grade, while the second level has one unit a few steps above grade. The top, two-story units run front to back and are side. The pattern is repeated inside seven distinctively different town houses, which have been traditional facedes.

The 28 unit ranging in price up to $60,500, are nearly completed and ready for occupancy. Only five are unsold.

In more than 18 years in construction, Linde has also built a few single-family houses. One of them, a classic traditional house on A Street SE, now belongs to a long-time Linde friend, Army Secretary Clifford Alexander.

Linde's approach to construction in the city often means bying land in neighborhoods he feels can be upgraded. About six years ago, for instance, Linde and reahor Henry E. Nichols combined forces to build a row of 13 houses inthe 1700 block of Corcoran Street. The surprisingly quick sale of those $50,000 houses surprised skeptical realty professionals. Now the dwellings are selling for nearly twice the price.

What about future Linde projects, now that a strong housing market has been established in-town for young buyers with good incomes?

"We have our area of experience an savvy," the builder said, "so we plan to keep on doing our own small-scale thing, modifying the floor plans to small where the sites are expensive but also building larger houses on prime locations. Both the sale and rental markets are strong here - if the product satisfies today's life styles and stays within the range of economic reality."