He is best known for designing the original plan of Nantes Cathedral in Brittany and commenced the building in 1434.

He also commenced the building of Johannisborg Castle, but died during the construction period.

He commenced the building of Muckross House on his estate in Killarney.

In 2012 the University commenced the building of a major new development for its School of Art & Design.

In 1907 he commenced the building of a modern photographic studio in the main street, where the Hotel Palcát now stands.

This led him to commence the building of three large cloth mills in Fall River in 1889.

Originally using the estate as a country house, he commenced the building of production halls in 1901 and moved in with the company the next year.

Neill-Wycik commenced the building of an expansion in December 1986.

In 1923 the City Council commenced the building of a concrete stand which could accommodate 2 000 spectators.

He commenced the building of Balfour Castle on the island on the site of an older structure.