John L. Wettlaufer was born on September 1, 1882, the son of George Wettlaufer and Nancy Lichti.

John's grandfather, Conrad, was born in Germany in 1826 and emigrated to Canada in 1850. The family settled in Wilmot Township in Waterloo County. Conrad and his wife,

Elizabeth, raised three children, including John's father, George, in a one-and-a-half storey stone house erected in 1853.

In 1878, George married Nancy Lichti, a Lutheran of German descent who was residing in North Easthope. George, who had been a farmer like his father, was an implements agent by 1881. George and Nancy had four boys, including John. By 1891, the family had relocated to Stratford.

The sons followed their father's footsteps and, by 1901, John was an implements agent alongside his older brothers Christopher and William. Despite being second generation, they still conversed in German. Business must have boomed for, in 1902, George had the first steam car in Stratford. A Stanley Steamer from Cleveland, it "didn't sound like a lawn mower. It went one worse and sounded like a tractor. It could be heard all over town."

John's stay at 16 Avon appears to have been relatively brief, lasting from late 1907, a year after the house was erected, until about 1909 when he moved to Toronto. However, during his time here, he married Sarah Boyd and they had a sons George and Charles, and daughter Irene in Stratford. Louis was born in Toronto in May 1909, suggesting that the family had already relocated there at the time of his birth. John and Sarah would have one more son, Edward, who was born in 1914.

By late 1900, Wettlaufer Bros was operating in Stratford, and it expanded rapidly as Canadian industry prospered in the early 1900s. The business specialized in cement mixers as construction using concrete boomed in Canada. It is difficult to ascertain the exact location of the business in Stratford, but city directories suggest it was at Mill Street (now Douglas Street) and Huron Street just north of the bridge. A sales office was located downtown Stratford. In 1904, the company set up its main factory in Mitchell, Ontario.

The Wettlaufer's were innovative businessmen. At the Good Roads Convention in Toronto in 1915, the company displayed rock crushers, tile machines, and concrete mixers, while gaernering particular attention for its road roller and paver. John and brother William were in charge. John further diversified his portfolio incorporating with partners to manufacture machinery and tools under the Canadian Drill & Chuck Company, Ltd. in 1915. John had at least one patent under his name for a concrete mixer. By 1921, Wettlaufer Bros had its head office and ware rooms at 178 Spadina Avenue, Toronto as well as offices in Buffalo and Detroit. It operated factories in Mitchell, Stratford, Galt, and Woodstock. Machinery for concrete production formed a significant part of its production. Perhaps most impressive, in an era of American branch plants setting up in Canada, Wettlaufer Bros was "the first purely Canadian firm to establish a plant and offices in the United States."

John's younger brother, Edward Litchy Wettlaufer, became president of Wettlaufer Bros in 1915. A golfer and hockey and football player, Edward also had interests in mining, discovering and developing Wettlaufer Mines in Cobalt, Ontario. He was also president of the National Potash Corporation.

John died in 1948 and Sarah in 1968. Both are buried in Avondale Cemetery