Lewis Tilleard Natusch (always known as Charles) was born on 4 October 1859 at London, England, the son of Emma Sarah Dixon and her husband, Charles Francis Natusch, a mercantile clerk. Social contact with people of other countries played a part in shaping his character. The family had connections with overseas interests through an insurance broking business founded by his grandfather, René Frederic Natusch, centred at Bishopsgate Street and at Lloyd's, London, with agencies at Trieste, Venice, Paris and Havana. Young Charles was educated at Bancroft's School, London, and studied architecture under I. Barlow Badcock at Staple Inn, Holborn, London, and W. Phelps at High Wycombe. From 1882 to 1883 he travelled to the United States and Canada; this broadened his approach to design. On 14 March 1883 at the parish church of Kelvedon, Essex, he married Ada Spencer. They were to have 10 children.
The liberal political views of Natusch coincided with those of the philanthropist Lady Angela Burdett-Coutts. She was influential in having him commissioned for town planning at Westcliffe, Southend-on-Sea, Essex, where he designed a five-storeyed hotel called Westward Ho (1883–84). This was his last major work before departing for New Zealand. With his wife and two young sons he sailed from England on 31 May 1886 on the clipper Canterbury, arriving in Wellington on 13 September. There, on behalf of the architectural firm of Atkins and Clere, he prepared a schedule of quantities to establish the losses arising from a fire that had swept down Lambton Quay. This helped establish CT (as he became known) not only as an architect but also as an expert quantity surveyor. In 1887 he set up his own office and in 1890 received approval for a horse-drawn tramway from Wellington to Island Bay, although this was not built. His clients soon included wealthy landowning families such as the Pharazyns, Riddifords, and Williamses. Many other prominent people later appeared on his client lists in Rangitikei, Hawke's Bay and Gisborne.
The 1880s depression prompted Natusch to move with his family to Masterton, the centre of a growing community. Their first residence burnt down on 24 November 1892 and their 22-month-old daughter, who was overlooked in the confusion, died in the fire. Another infant daughter died three months later. After building a second residence around 1893 Natusch moved to Pahiatua, where there was commercial work designing shops, then on to Napier in 1895, where he purchased the practice of the recently deceased architect Robert Lamb. Many fine houses were built in the ensuing period of prosperity. Natusch opened offices at Gisborne in 1900 and at Palmerston North in 1908. Meanwhile, commercial work had increased in Wellington and he moved the family back there in 1906. He designed several houses at Belmont, and by the time he semi-retired in 1926 the firm of C. Tilleard Natusch and Sons had become a major practice based in both Wellington and Napier.
Natusch is now best remembered for his legacy of fine houses. In some of his work, such as Bushy Park, Kai Iwi (1905), there is a classical Florentine-style treatment, while a less formal approach evident in other houses such as Maungaraupi, Marton (1906), recalls the English Tudor and related American styles. He was a versatile architect who followed his own convictions in the use of appropriate materials. His approach to design resulted in his best works being imbued with a distinctive character, refinement and integrity, seldom equalled by other designers of large houses in the period from 1890 to 1910. Among the best examples of the 25 or more built were Gwavas (1890) and Matapiro (1907) in Hawke's Bay, Erewhon in Taihape (1898), Westella in Feilding (1901), Silverford in Napier (1903), and Shalimar (1906) and Atawhai (1908) in Palmerston North. Matapiro, like many other homesteads, became the centre of a community with separate schoolroom, outbuildings and woolshed. Erewhon, high up on the Napier–Taihape Road, is a house of great charm and architectural integrity. Bricks were made in a kiln on the site and timber milled there and seasoned for 12 months before building commenced. The half-timber frame and brick-panel construction provided good insulation as well as giving a unique exterior expression to this high-country homestead.
Natusch was also innovative in his designs for commercial, industrial and ecclesiastical buildings. In the Wellington Stock Exchange (1906) he used reinforced concrete for its superior resistance to earthquakes. He improved lighting in woolstores by introducing sawtooth roof structures from 1895. He designed a number of churches and chapels, notably Te Aute College Chapel (1900), a chapel at St John's Cathedral, Napier (1904), and St Andrew's Presbyterian Church, Hastings (1906).
Charles Tilleard Natusch was a member and fellow of the New Zealand Institute of Architects. He was closely associated with the Anglican church as a synodsman and lay reader and held a commission in the Ranfurly Rifle Volunteers. He was an expert horseman and swordsman. Remembered as a somewhat restless and outspoken character who did not suffer fools gladly, he never accepted poor workmanship. Nevertheless, he was a kindly family man who was loyally supported by his wife, Ada, a warm-hearted woman who ensured that the family homes in Napier and Belmont lived up to their name of Whare Puare (the house with an open door). He died in his 92nd year, on 16 July 1951, at Paraparaumu, survived by Ada and eight children.