As Jennifer Lucchino and Freddie Croce converted a three-story brick building into a home and office, they experimented eagerly.

"We did treat this whole building as an opportunity to test some ideas about building design, spatial layout, materials and system design," Mr. Croce said.

The two architects, whose home is part of tomorrow's 16th annual Friendship House Tour, met 10 years ago in San Diego when Ms. Lucchino worked on Petco Park, home of the San Diego Padres.

"We settled in this neighborhood because we thought it was ripe for possibility," Ms. Lucchino said, adding that the building was attractive because of its location and sturdiness.

In January 2008, the husband and wife moved into the building, which sits between an Italian restaurant and a Vietnamese noodle shop on Penn Avenue. Marco, the couple's 3 1/2-year-old son, loves the third-floor outdoor deck, which doubles as a green roof.

Mr. Croce used what architects call a datum, or line, to organize space. That line is delineated by bamboo floors and low, painted bulkheads that hide mechanical systems. On the other side of the line are large, open spaces such as the second-floor living room and the third-floor dining room and kitchen.

"We used planes to define volume and space," Mr. Croce said. Color differentiates the bulkheads; some were painted green, others orange.

The family lives in the front of the building and sleeps in the back. With its use of deep, primary colors and vertical space, the home is light and airy, a little bit tree house meets clubhouse.

The place is full of aha moments, some of which Mr. Croce experienced while walking through the aisles of Home Depot or IKEA. The dining room table, which seats six, is an old drafting and layout table from his bachelor days. It rests on a steel frame and its wheels came from an old dolly. A tall white IKEA wardrobe serves as a pantry in the kitchen. A staircase banister is made of aluminum, a material Mr. Croce cut easily with a portable band saw.

Green design was used, too. The front of the building has a hard roof treated with a 96 percent reflective white coating that dramatically reduces its heat retention, which keeps the building cooler.

Rainwater flows underneath the trays that hold plants, which make up the green roof. Then, the water is diverted to a scupper, which is a hole in the side of a wall, through a downspout and into two 55-gallon rain barrels. The barrels' pipes slow the flow of rain water into the city's overloaded storm water system.

In the second-floor living room, black bookshelves Mr. Croce made from medium-density fiber board stretch 20 feet high to the ceiling. In between the shelves are 12 double-hung, insulated windows that afford a view of the street and allow in as much available light as possible.

Mr. Croce plans to build a conservatory ladder out of wood and steel that will roll back and forth on wheels, providing easy access to the books.

Off the living room, a corridor holds sliding white doors that conceal the washer, dryer and gas, forced-air heating system. Farther down the hall is Marco's bedroom and the master bedroom.

In the second-floor bathroom, a black bamboo counter floats between the sills of two frosted glass windows; beneath it is a long black IKEA sideboard. The sideboard, normally used in a living room, was bolted to the countertop, making it easy to clean the floor.

Above the bathroom counter hangs a 6-feet-wide, 30-inch-tall mirror that swings upward, revealing an extremely large medicine cabinet with lots of shelves. There's a white rectangular porcelain sink by Ron Bow and a stainless-steel shaft faucet by Cifial. The tub has Hans Grohe fixtures. Instead of ceramic tile, tub walls are lined in engineered stone tile that has a pattern that harmonizes well with the bamboo floor.

"Jen wanted natural light in the bathroom," Mr. Croce said, and that's why the space has two frosted glass windows.

The third floor contains a dining room, kitchen and outdoor deck. The kitchen island incorporates a breakfast bar, workspace, a gas stove and built-in cupboards that hold spices.

The kitchen island's painted black EQ countertops are made of green particle board by VT Industries. Three silver pendant lights hang over the breakfast bar.

The island's black counters contrast with IKEA cabinets covered in red laminate. Above the sink are four frosted glass cabinets. The Forbo tile floor, made from linseed oil, has shades of pumpkin and red.

Off the kitchen, a small deck and green roof offers a view of Garfield. The green roof, planted with red and green sedum, is a low ground cover of succulents that will flower into a colorful mix of purple, orange, yellow, red and green flowers next spring and summer. Eventually, the sedum will grow 8 to 12 inches high. Installed about a week ago, the plants came from Corso's Perennials of Sandusky, Ohio. The trays that hold the plants were provided by Live Roof, which is based in Michigan.

"After the first few weeks, we won't have to water it at all unless there's a drought," Ms. Lucchino said.

In the center of the green roof is the top of an old chimney, which the couple plan to skirt and use as a spot for barbecuing food once they install a custom-made grill. Corrugated metal siding frames the green roof.

The couple's commute to work entails walking down a flight of stairs. On the first floor, bifold glass doors that open to the street for special events allow pedestrians to see their architectural office, which is not quite finished, although the back of the space is filled with drafting tables and work areas. Eventually, the front of the first floor will contain a reception area, conference room and library.

The couple opened their business, inter*ARCHITECTURE, in 2003. They have designed space for businesses and homes. Both are also adjunct faculty in Carnegie Mellon University's architecture department.