In 1911, Folly Farm was bought by Zachary Merton, who asked Lutyens to extend it again. In 1912, Lutyens provided a dining room, master bedroom and further domestic services. He also added a large, T-shaped wing incorporating a two-sided cloistered court of monumental, battered brick buttresses which separated the new design visually from the earlier building. Internally, the later design is only connected to the former work by corridors at the ground and first-floor levels. The service areas were moved from the area once occupied by the original cottage, allowing the creation of a billiard room and sitting room. Paradoxically, perhaps, Lutyens designed this in his vernacular style as if it pre-dated his earlier extension at Folly Farm, and referred to the new addition as the ‘cowsheds’. As if to emphasise the formality of this earlier work, the new one is set down a level, making use of a gentle slope; the new creation is about mass and solidity, with its huge catslide roofs and monumental chimneys. Gertrude Jekyll was employed to design the gardens.
Successive owners altered the house to suit their needs: chimney stacks were removed, fireplaces lost, rooms subdivided, a staircase moved and, most significantly, the balconies in the hall removed. Moreover, after decades of alterations the hard architecture of the garden and the planting were in much need of attention.