The large main residence has two storeys plus an attic and basement as well as a one storey wing with lobby, kitchen and rooms for servants. The roofs are all pitched slate roofs. The timber frame has external vertical wooden cladding with finely profiled edges and there are carved decorations between the windows facing the road. The tall windows generously flood the three ground floor reception rooms with daylight.

The 1914 centenary exhibition which was held in Frognerparken in Oslo, was a very important showcase for Norwegian architecture, crafts and industrial production. The architect August Nielsen designed in collaboration with Rudolf E. Jacobsen several buildings for the exhibition, among others the agricultural buildings. The main residence at Jennestad which was built four years later, has much in common with the exhibition's farm house.