The Yorkshire house going underground

A concealed underground extension has given this house an extra 100sqm of space.

Sales Director Greg Parkin fought unsuccessfully for three years to extend the family home, a historic Cruck barn near Barnsley, until an extraordinary

alternative was proposed that completely transformed his way of thinking.

Instead of extending outwards, the extension would be below ground, creating a modern 100sqm living space - comprising two bedrooms, living room, bathroom, hall, kitchenette and store room – built under the garden.

“When we moved into the house it was just the right size, but when our second son was born we needed more space, particularly when people came to stay,”

says Greg.

Plans for a garden room were rejected on the grounds that it would alter the appearance of the historic long barn. An appeal was lodged and lost, so then Greg enlisted the help of a local architect Andrew Brown, from Design Space Architecture.

“We were thinking of building a glass box between the kitchen and detached garage to use as a dining room or flexible living area. That idea was also rejected,” recalls Greg. “We had been trying to extend for three years and were getting nowhere. Then Andrew said, why not go underground? We dismissed the idea at first because we thought it would be damp and dingy, but Andrew drew up some sketches and we realised it might work. We took it to planning and – to our amazement - it passed straight away.”

Greg and his then wife Heather deliberately wanted to keep the extension modern - a complete contrast to the original 550-year-old Cruck house – so they

could have the best of both worlds.

“I wanted to have a bit of fun with it and create a bright, bold, colourful family space that we could all enjoy, but which would be flexible enough to evolve with the family's changing needs,” says Greg.

Building work began while the family were on holiday. They left with a lawn and returned to find a gaping hole - a five metre deep, 100sqm pit - in in its place. All the soil had been taken away by a convoy of diggers and trucks.

Ground testing revealed a base level of loose rock and shale which was easy to dig out and created firm boundaries in which to build the underground

extension. The walls were built out of polystyrene bricks filled with waterproof concrete which were assembled, Lego-fashion, within a few days. Breezeblock walls were built inside this outer layer and the building damp proofed with a waterproof membrane, then heavily insulated.

At the same time Greg oversaw the complex drainage system. Most of the rainwater runs off the glass roof of the light well and dissipates naturally

through six inches of surface soil and grass. The rest runs into channels and is pumped into the main drains.

The shell of the underground building, which includes steel support beams and a concrete covered steel mesh roof system, was completed in five months. The biggest challenge was fitting the light well. It weighs just under a ton and had to be supported by a ring beam.

Joining the extension to the main house was the turning point. At first the builders thought one whole side of the older house would have to be

underpinned, but the rock beneath was so solid that a structural engineer said it wouldn't be necessary. Instead the wall is made of three layers of blockwork and two cavities.

“While the hole was dug between the old and new properties, and a new staircase built, we moved into rented accommodation nearby for two months,” says Greg. “When we came home everywhere was freezing cold and covered in dust, but it was a great moment. It was the turning point of the build because we could start to see it all come together.”

The extension had to dry out while the builders made sure it was completely waterproof. “We didn't want to plaster out and decorate and then find there was a problem. But the structure is amazing. It's just like a large, solid bunker, only with masses of light.”

Inside, the curved red cedar wall was inspired by the Velodrome. “It took eight weeks for the wood to come from Canada but it was worth the wait

– it's my favourite feature,” says Greg, who is a keen cyclist. “It's fitted to a curved frame and is lit from the top – the slit windows are just above ground level – and also from the floor. I enjoyed sourcing the furniture. I wanted it to be bright, colourful and modern - very different to the main house. I wanted great design on a budget.”

Slit windows and insets add interest to the large expanse of curved timber. The skimmed floor withstands the rigours of day-to-day living while the Ligne Rose sofa, dining table from Made and Vitra chairs from Nest bring clean, modern lines and plenty of colour into the room.

The extension is fitted with a heat recovery system and high spec electrics, including mood lighting, both from Norcroft Energy, which bis based in Dodworth, Barnsley.

There were a number of times during the build when the budget was spiraling out of control and they thought they might have made a big mistake, but agreed that in the end it was definitely the right thing to do.

The extension almost doubled their living space. And as family circumstances have changed, and the house is now only occupied by Greg, the underground section is to become Air B and B accommodation which can easily be separated from the original house.

“It's an ideal location for Air B and B,” says Greg. “It's modern, private and well disguised under layers of soil and turf. When you look at the flower beds and paths around the garden you hardly know there is a building underneath.”


Andrew Brown Architect: 01226 762697.

Norcroft Energy, heat recovery and ventilation system and electrics: 01226 763127,

Home Automation including cinema: 07768 456869,

Aluminium Trade Frames: 0161 653 8900,

Wardrobes, Supafit bedrooms: 0114 250 7665,