This four-floor residence was built in 1904 for Emma F. Platt and was designed by architect William A. Knowles. The contractor, W. L. Moore constructed the house for a total cost of $9400. According to the 1910 United States Census, Charles B. Platt (age 58) lived here with his wife Emma F. Platt (age 48), along with their daughter Gladys A. Platt (age 18) and a house servant from Sweden, Ellen Loeser (age 26).

Charles B. Platt was born in Connecticut in January 1852 and was the second vice president of J. A. Folger Company, the local manufacturer of coffee and teas. His wife Emma F. Platt was born in California in May 1861.

The residence was sold in August 1922 to Marion R. Roth for $20,000. Marion R. Roth was born in California in 1897 to German parents. Her husband Lester L. Roth was also a native Californian, born to French parents in 1884. He was the head of the Roth Blum Packing Company located at 1490 Fairfax Avenue in the Bayview district, once known as “Butchertown.”

Architect William A. Knowles was born in New York on January 3, 1873; as a child he came west with his contractor father, also named William. He lived in Oakland with his wife and son and was responsible for many of the distinguished buildings in that city. He is primarily noted for his designs of shingled residences (i.e., 3235 Pacific Avenue). However he was certainly adept at building with stucco, as seen in The Platt House. His designs include 3236 Pacific Avenue (1905), 3240 Pacific Avenue (1908), 123 Edgewood Avenue (1906), 3839 Jackson Street (1905) and the California Club (1907) at 1750 Clay Street. Knowles died on November 11, 1958 at the age of 85.

The Platt House was altered several times during the 1920s. In 1922 a bathroom and garage were added for $15,000 The garage was originally used as a ballroom. At that time the wood trim was also removed from the dining and living rooms. In 1926 a breakfast room was constructed for a fee of $1500.

More recent alterations include re-establishing the home’s original five bedrooms; replacing the outdated electrical wiring and plumbing systems; extending the kitchen; and reworking the ground floor to create a better flow. At the entrance, the steps, paneled sides, and front doors are new. Many layers of paint were removed from the exterior pediment and surround framing the entry, which is believed to be original.