For 20 years, Spencer Leineweber ran her architectural practice in the "mini" Mendonca Building, which she owned with her husband, Michael. Constructed in 1913 at the corner of Smith and Hotel streets, the building measures just 980 square feet on each of its levels — a basement, first floor and second floor.

"It’s small, but it worked well for my firm’s needs," recalled Leineweber, who is a professor and graduate chairwoman of the University of Hawaii’s School of Architecture. "For one thing, it had high arched windows, which provided really good natural light. It also had a basement for storage. Back then, both were important for an architect’s office, although they’re less so today with the advent of computers for drawing."

When a friend, who was a Navy nurse during World War II, learned the Leinewebers had purchased the building, she chuckled. "During the war she waited outside the building for more than an hour, thinking she was in a ration line for bread," Leineweber said. "When she finally got to the front door, she found out the building was a brothel. There were a lot of men standing in line, but she hadn’t paid attention to that — and none of them told her what the line was for!"

Participants will pick up intriguing tidbits like that during a two-hour, two-mile walking tour of Chinatown that the Hono lulu chapter of the American Institute of Architects will be hosting Saturday as part of its fifth annual observance of Architecture Month.

The tour will spotlight more than a dozen architecturally significant buildings in Chinatown, the oldest intact commercial area on Oahu. Constructed between 1854 and 1965, the buildings on the route include the Kame ha meha V Post Office, Yoko hama Specie Building, Nippu Jiji Building, Oahu Market, Wo Fat Building and Hawaii Theatre.

About 20 members of AIA Hono lulu, including Leineweber, will be serving as guides and "building docents" for the tour. As a historical architect, Leineweber has worked on numerous conservation proj ects in Hawaii as well as new structures in historic preservation areas such as Chinatown.

The two-story "main" Mendonca Building is across from the building she and her husband sold in 2002. Built in 1901, it covers a full block on Hotel Street, which makes it the largest historic building in Chinatown.

"Joseph P. Mendonca was a luna (supervisor) for Kane ohe Ranch," Leineweber said. "He owned a lot of property in Chinatown, all of which had windows with either red frames or red brick around them. That was his building identity, to let everyone know how many properties he owned. At one time there were more than 10 buildings in Chinatown with that signature red trim."

Two devastating fires swept through Chinatown in 1886 and 1900, reducing the majority of its wooden structures to ashes. Today, Hono lulu’s oldest buildings are clustered at the edge of Chinatown, around the intersection of Merchant and Bethel streets where the fires didn’t reach. The two-story Kame ha meha V Post Office, built in 1871 on one corner of that intersection, is one of Leineweber’s favorite buildings.

"Initially you picked up your mail ‘by language’ — Chinese, Japa nese, Hawaiian, English and ‘other’ at individual windows," she said. "In the 1890s brass mailboxes were added under the covered arcade. There’s still a small window on the Diamond Head side where you just bought stamps. From the second-floor lanai, you could watch all the activity on the street, which was then the center of town. Also notable are the Tuscan columns and the curved balcony whose wood jigsaw work sunshade was added later."

In 1976 Leineweber was a member of the team that restored this elegant Hono lulu landmark, which was added to the National Register of Historic Places in 1972. "It was one of the first restoration proj ects that I worked on as the proj ect architect for the firm Anderson and Rein hardt," she said. "There’s so much more I can say about this building; in fact, that’s where I’ll be and what I’ll be doing during the walking tour on Saturday."

Cheryl Chee Tsutsumi is a Honolulu-based freelance writer whose travel features have won multiple Society of American Travel Writers awards.