In 1670 the Duke of Lauderdale commissioned Bruce to remodel Thirlestane Castle, his 16th-century tower house in the Border country. Bruce, working with King's master mason Robert Mylne, extended the building with new corner pavilions and a new entrance, and re-planned the interior. Lauderdale continued to employ Bruce, often working closely with Lord Haltoun, Lauderdale's brother, during the 1670s, on his homes at Brunstane near Edinburgh, and Lethington (later renamed Lennoxlove), as well as commissioning a design for new gates at his English property, Ham House, near London, in 1671. At Ham Bruce may have had further involvement with the remodelling works going on there, under the direction of the English architect William Samwell. While engaged at Thirlestane, Bruce also designed the nearby Lauder Kirk, his only complete church. One of very few 17th century cruciform-plan churches in Scotland, it may have been inspired by François Mansart's similar church at Balleroy in France.