Ferstad is one of the few farms in Os that have not belonged under Lyse Monastery or any of the other large agricultural estates. From 1670 and for 200 years hence, priests and officers have been the owners, and they naturally had others to run the property for them. At the end of the 19th century the farm also served as a guesthouse.
The oldest part of the main house is from 1645, after all the houses on the farm had burned. This was before the time when government employees were given agricultural estates, and this building was an ordinary farmhouse. It was in the 1700s that the house gained its stately appearance. At that time a servants’ quarters and a house for the oldest generation were added as wings to the main house.
The main house has been restored and contains many fine details in the interior.