Originally built in the 70s, this gable fronted cottage overlooking the sea needed extensive work. Existing flat roofed extensions were at the end of their life and additional space was required for a growing family. The house was also not making the most of its spectacular setting, in an Area of Outstanding Natural Beauty backing on to National Trust land and the dramatic cliffs of Wembury Bay.

The brief was always to maintain something of the original house. The white gable is a familiar marker in the landscape and provided the base for the transformation. The house has been stripped back to its core and the land adjacent excavated to double the footprint. The original gable has been mirrored with a 1.8m wide gap between. Clad in slate, this new gable hunkers into the sloping site and the two volumes have an intuitive relationship with their surroundings. Recognisable as a simple repeat of volumes they offset comfortably against the wonderful disorder of the wooded valley.

The separation allowed us to slip-in the circulation necessary for the 4 bedroom layout centrally, and helped to define zones within the more open ground floor. More importantly it left space for the landscape to permeate the building. Allowing views from the front door to the sea, this space creates a sense of connection to the surroundings and draws you through the house.

At ground floor the seaward elevation is completely opened up to the view with extensive glazing, and an open plan layout creates a sense of space and connection to the surroundings. The double height atrium has large windows at first floor, washing the space with light and allowing views through. The stair rises in this space to a balcony from which the 4 double rooms are accessed.

The extension was built as sustainably as possible with appropriately oriented and situated openings, timber frame with as much insulation as the budget would allow and on a shoestring – many of the finishes being kept and upcycled from what was removed from the old house.

The project was a collaboration between Zac Monro Architects in London and Tim Offer Architects in Devon, and it was the subject of the TV series Inside Out Homes on C4

• Winner Build Architecture Award 2017