A PLAYHOUSE remodeled from a jungle gym has won an award from the Washington Metropolitan Chapter of the American Institute of Architects. There's hope for architecture after all.

When the AIA can admit that a good playhouse is as worthy of an award as a monster office building (though admittedly not as profitable) it's a sign from the heavens that this year the world will not be totally encased in concrete.

Perhaps Superman has caused the world to turn around the other way -- the jungle gym-into-playhouse remodeling even cost $900 -- much less than manufactured play equipment of the same size.

Reginald H. Cude, a Washington architect, has a daughter, Jennifer, then 4, who went to the Rock Springs Cooperative Preschool at 50110 Little Falls Road in Arlington. The playschool is for children 3 and 4 years old. fThat's the adventurous age when equipment had better be designed well.

In the play yard was a jungle gym made of a steel pipe -- an unattractive nuisance of the sort that turns up often. The infernal thing was a peril. This distance between the pipes was too high for children of that age. The children couldn't resist trying to climb and swing on it. But the teachers couldn't devote every minute to trying to keep them from hurting themselves.

The school thought the students' fathers should come over on Saturday and tear it down. But the pipes were set in concrete, no easier for the fathers to tear down than the teachers to patrol.

Fortunately, the preschool had the foresight to have an architect in the parents cooperative. Cude is a vice president with Mariani Associates, Architects. He usually designs schools, hospitals, big buildings. But he knows that architecture at its best should begin early to make life safe, comfortable, and even a bit of fun. "I felt sort of guilty," said Cude, "because I hadn't put in my Saturdays working for the school. So I designed this for them, instead."

Cude used the steel gym as the framework and the hand railing for a series of plywood floors, two feet apart, attached with a U-shaped clamp.Plywood ladders give a safe climb from one floor to the next. A rope is zigzagged between the bars to give more protection against falling. A plywood roof serves as a wall in some places.

The whole form is an open air playhouse, a fantasy structure that pulls even the shyest, least venturesome children to try their strenghts.

"The wood materials visually soften the steel frame to blend with the wooded site," said Cude. He thinks the principles involved -- using the pipe structure to support sturdy wood floors -- could work in smaller jungle gyms in individual families' back yards. "Just be sure the gym itself is well-anchoared," he said.

Edgar Slack of Arlington was the contractor.

Jennifer is 9 now and way up there in school. But after five years, children are still playing in safety on the Cude design.

Another recreation structure won an award, this one for the Cooper-Lecky partnership. This one was on a vastly bigger scale: the District of Columbia Center for Therapeutic Recreation, 3030 G St. SE. The five zones of the complex hold a gym/auditorium, swimming pool, classrooms, administration and a preschool. All except the preschool are grouped around the enclosed central court with its brilliant skylight. The central court, the architects said, makes it easier to find the different facilities, serves as a friendly, informal place to meet other people and helps the staff to control the building.

George Martin was the contractor; Vincent Lee-Thorp, mechanical/electrical engineers; and K.C.E. structural engineers. The building was completed in 1977.

Six other projects won awards.

Calvert Heights on High Street in Chestertown, Md., was designed by the Chesapeake Design Group (Donlyn Lyndon, John W. Hill and Roger K. Lewis). The 22-unit housing project has both two- and three-bedroom units. Each house has a front and rear yard, a porch (even if their columns do look rather spindly) and a parking place. A grassy area and tot lot serve the children. The children can go anywhere in the project without having to cross streets or driveways. The units have nice tall windows. The brick and the roof colors were chosen to harmonize with the neighborhood. Even the pale peach color is in the Eastern Shore tradition. The dining and kitchen spaces are combined in the manner common to the area. Each unit has a bath and a half.

Harkins Commercial was the contractor, Larry O. Degelman of College Station, Tex., the engineer. The development was completed in 1978.

The Foundry, 1055 Thomas Jefferson St., NW, was built in 1856 as a foundry. Later it became a Civil War animal hospital and the gas company warehouse. The office and shopping mall with its oak, brick, mirror and glass has a friendly, comfortable, warm feeling that seems to chug along with its neighbor, the C & O Canal.

Arthur Cotton Moore Associates were the architects for the schematic design, design development, interior design of lobbies, elevator and public spaces and design finished. Vlastimil Koubek Associates did the construction documents. John Stolorow of California was the interior designer for the Foundry restaurant. Tishman Realty & Construction Co. of New York was the contractor. Inland Steel Development Corp. is the owner of the 1975 building.

The Washington Mall master plan and circulation systems were the National Park Service's first step in closing the Mall to automobile traffic, a laudable goal surely. Skidmore Owings & Merrill's Washington office were the architects. The project replaced Washington and Adams Drives with pedestrian walks. Unfortunately the walks are surfaced with crushed stone, slurried clay, sand and water. It's difficult and uncomfortable to walk on, even if, as the archiatects say, the surfacing was used in Versailles and the Tuilleries.

Carson & Gruman Co. was the contractor.

Arnold Associates were the landscape architects with SOM for Constitution Gardens, a pleasant, romantic landscape which comes as a relief from the formality of the Mall. And, of course, the gardens are a vast improvement over the World War I tempos which once desecrated the site. The six-acre lake, meadows and trees are bounded by Constitution Avenue on the north, the Lincoln Memorial Reflecting Pool on the south, 17th Street on the east and Henry Bacon Drive on the west.

Flippo Construction Co. was the contractor.

Northhamption Golf Clubhouse at Largo, Md., was designed by Saunders, Cheng & Appleton Ltd. on a 22-acre site surrounded by the Northhampton community. The pavilion-like structure houses the pro shop and snack bar under interlocking half-trust, gabled structures of sawed-wood paneling and exposed beams. The project was notable for coming in at $15,000 under budget.

The other prize winner was Hugh Newell Jacobsen's sensitive house for an artist. An article about that house and another Jacoabsen award winner with photographs by award-winning architectural photographer Robert Lautman will run in Living June 22.

Judges were Donald Canty, editor of the AIA Journal; Sarah P. Harkness, Architects Collaborative of Cambridge; and Louis Sauer, head of the Carnegie-Mellon University (pittsburgh, Pa.) architecture department. Seventy-four projects were submitted, all completed after Jan. 1, 1974.

The awards this year were notable for going to projects and architectural firms both small and large. Half the awards, as usual, were won by names that always appear on awards lists, but at least a few are people we don't always hear about, who've designed buildings that haven't already won umpteen awards. But all the winners are to be congratulated for making at least some effort at serving people rather than architectural egos.