RIBA House of the Year contender: dramatic, ultra-modern north London home shortlisted for top award following epic five-year build

Ask an architect to design you a home and, within reason, the law, and your budget, you can have whatever you want — and, if you are lucky, you’ll get even more.

Which is what has just happened in Highgate, where a marathon five-year build has created an award-winning double-fronted house longlisted for this year’s prestigious RIBA House of the Year.

Designing this outstanding dream home set a benchmark in style and quality for award-winning young married architects, Cousins & Cousins.

Ben and Jelena Cousins met at university and married in 2000, starting their own practice in 2012, when they’d worked on lots of domestic architecture.

That year, their company builder asked their advice. He’d found a large plot that he wanted to build a big modern house on but like most plots, it was complicated.

First, there was a “falling down” Sixties house already on it. Second, it was in a conservation area in Hampstead, and third, a big old tree in the garden might not be removable, by law.

Married with children and in his mid-forties, the builder already lived in a nice period house with a big garden, but dreamed of crafting something ultra-modern, large and light, with a swimming pool and cinema. His wife, a keen gardener, wanted a visual and actual connection to outdoors.

When Ben visited he saw the poor state of both house and tree, which a tree specialist confirmed.

Nevertheless, to buy a plot on that basis would still be risky, for only the planners can make the final call, and the builder would have to buy it before going to planning.

From their experience, Ben and Jelena felt pretty sure planners would let them replace the dilapidated house with another, as long as it suited the area, so they designed a home to fit the bill: a double-fronted villa whose front has similar height and massing to the neighbour’s, and also gives a nod to the local Arts and Crafts vibe.

It would be made in elegant modern bricks with stucco bands across, with a seamed zinc roof and simple lines.

The house would be a tale of two halves, pushing out at the back into a striking glassy, boxy modern house that’s invisible from the street. To this, a ground-level glass extension would provide further living space.

Finally, digging out below the entire house allowed that swimming pool and cinema.

However, to keep this lower level as light and airy as possible, the architects proposed plunging a three-storey volume right down through the house, and adding an incredible, sculptural spiral staircase to the lower floor.

Just in case planners insisted on keeping the old tree, they also prepared a design for a smaller house to work round it. Since this Plan B minimised his risk, the builder bought his plot.

Ben and Jelena went to pre-planning in spring 2013. Jelena says they were encouraged by Haringey’s welcoming attitude to thoughtful modern design. Unusually in a conservation area, there were no objections or changes required.

That winter, the builder got to work on his extraordinary seven-bedroom home. After tearing down the old house, a massive excavation for the 6,500sq ft new one took months.

The design keeps the house very open. At its heart a cantilevered oak open-tread staircase lets light through, so the gardens are visible from the front door. Two concrete cores either side of these stairs are attractively board-marked, making watery ripples enhanced by sunlight.

This surface interest complements beautiful brown Travertine used elsewhere, and the grain of oak. Everywhere, vistas of garden, or views into other rooms delight and add to a sense of space and flow.

Ben points out narrow shadow gaps and full-height oak doors. Though technically challenging, the finish everywhere is immaculate, all done by this builder client and his team.

Tricky polished plaster ceilings; special metallic plaster to clad that spiral staircase; a bespoke stained oak and porcelain kitchen; a Travertine feature wall to hold the see-through fire? No problem.

“From the start, it was a collaborative project,” Jelena explains. Ben adds, “Our builder is very interested in detail. I’ve never met a builder with such a refined sensibility; he is so precise and meticulous that on one job he did there was no snagging.

“Everything was perfect. We were impressed by what he did here. He’s our dream builder.”

Risk, innovation, and meticulous attention to detail meant that it took five years, but it’s worth it.