The site of a former underground reservoir struck a chord with Richard Bennett and Felicia Böhm, who featured on Grand Designs in 2019, but their earth shelter build wasn't without its setbacks. 

grand designs tv house converted reservoir hull 2019 exterior

Image: One wall of the reservoir frames the entrance to the courtyard, with the concrete broken down and left in its original state; the plan is to allow it to age naturally over the years. Photo: Andy Haslam

When Richard Bennett and Felicia Böhm bought this site near the Humber estuary from Yorkshire Water for £98,000 in 2013, it was a dark, cavernous concrete underground reservoir. Built in the late 1950s, it originally held up to 2.5 million litres of water. 

Despite the industrial nature of the site, Richard and Felicia were attracted by the possibility of creating an eco-friendly home and exploring the concept of an earth shelter, which harnesses the thermal properties of the ground to reduce energy use.

Watch the episode: Hull, 2019

Hands-on approach

Richard, an independent building services engineering consultant, also wanted to return from working abroad and in London to his native Yorkshire, and felt a deep emotional pull towards the site. ‘I got the idea that the place wanted to be set free. The empty reservoir had been down there on its own long enough, so I felt that the void needed to disappear to let the sunlight in,’ he explains.

grand designs tv house converted reservoir hull 2019 - courtyard garden

Image: Steel pipes from the reservoir were repurposed as planters. The pipes have developed a patina over the years. Photo: Andy Haslam

Neither Richard or Felicia are strangers to a building site: they met working on a construction project in Hungary where Felicia, whose mother and grandfather were both architects. With this background, both were hands-on throughout the project and Richard undertook much of the design work himself, supported by Ilkley-based architect Richard Addenbrook for the final architectural polishing, along with a structural engineer and a thermal-modelling expert.

Read more: How to project manage your own self build

Low carbon considerations 

First on the list of jobs was to demolish all 650 square metres of the reservoir’s roof, leaving the foundation slab and the retaining walls as the basis for the house.

Working to the principles of a low-carbon build meant recycling as much of the structure as possible, so the rubble from the roof was saved and used to help fill in the courtyard. Everything else, including the supporting steel pillars, was stripped out and sold to the steelwork fabricator for recycling, reducing the cost of the new metalwork. Not one skip was hired throughout the build. 

grand designs tv house converted reservoir hull 2019 kitchen

Image: The bare concrete walls were painstakingly ground by Felicia. The kitchen units are from Ikea and the overall sense is a welcoming home with a strong industrial slant. Photo: Andy Haslam

In the deep end 

The house sits in the huge space, which had previously been filled with water and rises a metre above the reservoir’s perimeter walls to allow light in through clerestory windows. Rooms are pushed to the edges of the site, looking out into a central courtyard. The main structure of the new building is a super-slim steel frame fixed to the concrete walls. 

A boarded, insulated roof has been covered with a waterproof rubber membrane after the original plan for a living roof was ditched due to the expense, cutting the roofing costs from around £ 40,000-£50,000 to £12,000.

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The only remaining aspect of the reservoir’s superstructure is the valve tower, a building that once controlled the release of water, which will eventually be converted into an office. It stands sentry-like above the broken-out entrance, a section of the retaining wall deliberately left to look like a ruin.

Read more: 9 of the best home conversions featured on Grand Designs

grand designs tv house converted reservoir hull 2019 living room

Image: High clerestory windows peep over the edge of the reservoir walls, the light highlighting the texture of the ground concrete. Photo: Andy Haslam

A rocky road 

Creating this cosy family home from such an unprepossessing bunker was never going to be easy, but Richard and Felicia didn’t expect to face far more serious battles along the way, too. In late spring 2014, just as the tank roof had been demolished in preparation for the build, Richard developed cancer, and subsequently a dangerous blood infection, which almost killed him. Work on the project had to come to a halt for three years.

For six years the family were in a cramped rented flat, where daughter Maya had no garden to play in. Although the house was not finished when the family moved in last summer, the need for space and not to be paying rent was pressing.

grand designs tv house in converted reservoir in hull - 2019

Image: Scottish larch cladding allows the exterior to blend with trees that surround the site. Photo: Andy Haslam

A work in progress

Work continues on making all of the spaces in the 455 square metre house fully habitable. An open-plan living/kitchen/dining area is complemented by a mezzanine snug and eventually there will be three to four bedrooms, three additional multipurpose rooms, a self-contained studio annexe for Felicia and a workshop for Richard.

There is still work to do, but so far Richard and Felicia have spent less than £150,000 on the build, in spite of the huge ambition of the project. This was done by planning each stage with precision and doing much of the work themselves, including fixing the roof membrane in place and, for Felicia, days spent laboriously grounding down the concrete walls. ‘After the illness there was a tectonic redesign philosophy to make everything self-buildable due to having very limited funds,’ says Richard. ‘But for any self-builder looking at a restricted budget, I would say that giving yourself time in the schedule is vital. So is writing down a list of everything that could possibly go wrong and working out what to do in those instances.’


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