Surveyor to the Grosvenor family"s London estates from 1821, he was involved in the initial stages of the development of Belgravia and Bloomsbury, and also designed country houses in a picturesque Gothic style. After serving an apprenticeship with a builder in Plymouth, he moved to London at the age of 21. At the age of 28 he was employed as clerk of the works at Normanton Park, under Samuel Pepys Cockerell.
Following Cockerell"s retirement he was retained by Sir Gilbert Heathcote to complete the alterations in progress.
He then set up in business as an architect and builder, and in 1821 was appointed surveyor to Earl Grosvenor"s London estates, in succession to William Porden. He had previously altered two houses on the estate, in Grosvenor Square.
During his tenure the basic layout of Belgravia was developed, but he died before much construction had been carried out. Buildings which Cundy built or altered significantly include Middleton Park and Osterley for the Earl of Jersey, Tottenham Park in Wiltshire, Hawarden Castle, Burton Constable, Syon House, Northumberland House in London and Wytham in Oxfordshire.
He exhibited several designs for these and other buildings at the Royal Academy.
He died 28 December. Cundy married Mary Hubert in 1789. They had six sons: Thomas (1790–1867), also an architect.
James (1793–1826, a mason).
Samuel (c 1794-1819). Joseph (1795–1875, an architect and builder). William (c 1797-1829).
And John (c 1802-1828).