Vellefaux was qualified as a master mason in 1585, sworn by the king as responsible of masonry works and topographer for Mr.
Prince de Conti, in 1611, great topographer of Saint-Germain-des-Prés, sworn mason controller of the buildings of the Hôtel-Dieu, in 1625.
Before 1610, he married Laurence Hébert, daughter of a merchant living in Saint-Germain-des-Prés and had three daughters: one, Laurence married a king's doctor, Valentin Hieraulme and the other, Anne, joined Gilles Sanglier, squire, lord of Noblaye in Touraine.
The third, Étiennette Vellefaux, married architect Christophe Gamard who succeeded his father-in-law as seer of the abbey Saint-Germain-des-Prés.
He was the first builder of the Hôpital Saint-Louis, on the plans of Claude Chastillon and François Quesnel, in 1607.