Photography by Will Scott, courtesy of De Rosee Sa

De Rosee Sa are a hands-on London architecture and design practice. Led by husband-and-wife duo, Max De Rosee and Claire Sa, they recently completed a lakeside cabin for De Rosee’s parents that the team not only designed but also built themselves. Total budget: £25,000 ($36,281)—it pays to have an architect in the family.

The design replaced a dilapidated building on the property.

The live-edge cladding is shiplapped spruce treated with the firm’s secret formula: “It was blackened and sealed with recycled tractor oil donated by a local farmer.”

Members of the firm took many weekend trips to Belgium to work on the construction.

The cabin has glazed doors on three sides and double windows on the fourth.

The western elevation has a cleverly integrated pocket porch.

The porch is used as an outdoor mudroom.

Thanks to the soaring ceiling, the 35-square-meter (approximately 376-square-foot) interior feels surprisingly spacious; it’s heated by a wood stove.