It shouldn’t do. Most companies will do all the interior work first, and the last job to do will be creating the opening from the house to the conversion. A reputable company will make sure they cause as little disruption as possible during this time.
South Brent
South Brent (population 2,822) is a huge village on the southern edge of Dartmoor, England, in the valley of the River Avon. The parish includes the little hamlets of Aish, Harbourneford, Lutton, Brent Mill, and also lots of scattered farmhouses. It is five miles (8 kilometres) north-east of Ivybridge and also 14 miles (22 km) east-northeast of Plymouth. On the high moorlands are many hut circles, rooms, and barrows, all dating from the Bronze Age. The manor of Brent came from Buckfast Abbey from the time of the foundation of the abbey in the very early 11th century. It was bought at the Dissolution by Sir William Petre, a big receiver of monastic spoils in South Devon. South Brent was initially a woollen as well as market centre with two yearly fairs. Brent Hill is the steep hill just outside the town where it takes its name (Old English brant-- steep). On it are the ruins of an old building, supposed to have been a chapel, as well as of a windmill constructed concerning 1790.