A Modern Home Built on the Sea Wall

Sandwiched between traditional riverside houses, the newly completed Riverhouse stands within an Area of Outstanding Natural Beauty in the historic town of Dartmouth, where it quite literally hugs the bank of the River Dart. For Devon architect Robert Seymour, this uncompromisingly modern house has proved to be both a dream job and a logistical nightmare. Nothing about the project was straightforward – from gaining planning consent to constructing the technically demanding contemporary home – and stressful new challenges arose around every corner.

“When I was first invited to visit the site I already knew the place extremely well,” says Robert, a long-term resident of Dartmouth. “Ten years ago, I was also responsible for designing the L-shaped house which stands right next door, and this gave me a real insight into some of the challenges which lay ahead.”

Situated at the base of a 20-metre-high cliff and perched directly on the water’s edge, the setting for this breathtakingly contemporary property is both magnificent and daunting. The ancient town and deepwater port of Dartmouth is in a truly picturesque location on the River Dart, with steep wooded hills rising up on either side.

“My client is a London businessman who enjoys sailing, and would often visit the area with his wife for that reason,” Robert explains, “so when the opportunity arose to buy a house in the town they jumped at the chance, mainly due to the amazing location right beside the water and the fantastic sweeping views.”

Robert was initially invited to come up with suggestions to alter and improve the existing timber framed house which stood here. However, it soon became clear that his clients’ dreams of an unashamedly contemporary, sustainable home could only be met by designing a brand new replacement house for the site.

Inspired by the spectacular natural setting, Robert worked with a team of experts to develop his clients’ wish list into an ambitious two storey 600m2 design, incorporating glass walls, floors and folding sliding doors in order to maximise the glorious estuary views beyond and reflect the water lapping directly below the building — casting dappled reflections around the interiors. “It’s quite a long, narrow site, which is hemmed in by the cliff and high boundary walls, so one of the main concerns was bringing natural light into all of the rooms,” explains Robert, who solved this potential problem by effectively splitting the floorplan in two and linking these halves with a narrow courtyard, whilst introducing skylights to many of the rooms.

A copper barrel-vaulted roof appears to float above the white rendered walls, supported on an upstand of glazing which drops natural light down into the L-shaped living-cum-dining room and kitchen, located on the first floor. Here, the free-standing polished plaster fireplace and its suspended stainless steel flue act as a low room divider, and a projecting bay window draws you towards the water and its magnificent view.

The house has been designed as a reverse-level affair, with four en suite bedrooms located on the ground floor, and the master bedroom has its own projecting glass bay overlooking the estuary with a glazed floor panel positioned directly above the water. A simple, clear glass partition is all that stands between the egg-shaped bath and the bedroom itself, allowing the bather to enjoy views of passing boats outside the window.

Unprepared to compromise, Robert also realised that such an overtly contemporary proposal would meet with widespread disapproval from residents of the town. “The site’s in an extremely sensitive setting – on the edge of a Conservation Area – and we knew from the very start that gaining planning permission would be a battle,” he recalls. “But it was never the intention that the house should simply ‘fit in’ — we wanted its design to stand out and rely on its own merits.”

Even so, the barrage of local protest still came as rather a shock to Robert, who admits that he takes such criticism extremely personally. Fortunately, the local council were more enlightened, and ultimately approved the plans following 18 months of detailed negotiations with the various authorities.

“One of the many planning conditions of the build involved bringing all of the materials to site over the water rather than by road, to avoid clogging up the traffic,” Robert explains. “This meant that the main contractor, Midas Construction, needed to build a temporary crane platform in the water and then deliver everything by barge from the other side of the estuary.”

Another potential hazard was the fact that Riverhouse stands on part of the shoreline designated by the Environment Agency as high risk in terms of flooding. Determined to insure against future climate change, Robert designed a robust but attractive bund wall to wrap around the site. This rises more than one metre above the lowest floor level, appearing as triple-glazed balustrades in places, and was constructed using a combination of water-resistant concrete and stonework, with bonded sheets of clear laminated glass to ensure that the building effectively sits in an impervious dish.

“The house was designed to be built using a limited palette of high-quality materials: glass, stainless steel, painted metal, copper, render and natural wood,” Robert explains. “There are none of the usual details – no skirting boards or window frames – because everything has been pared down into its simplest form.”

To achieve such minimalism took far longer than constructing a standard house. Time-consuming shadow gaps were created, whilst window frames are concealed within walls and electrically operated blinds are cleverly hidden from view when not in use. Staircase balustrades are made from frameless glazing, without even a handrail to spoil the unfussy lines of the house.

The latest technology has also been incorporated throughout the property. The house boasts a sophisticated multi-room music system, a TV which rises out from the fireplace feature at the touch of a button and a glass screen which slides across the main living space — acting as a room divider to separate it from the rest of the house as and when required.

Making the best use of environmentally friendly technology was also a priority for Robert’s clients and the decision was taken to sink pipes into the Dart so that heat may be extracted from the river by means of a heat exchanger — a process which required special permission from the Duchy of Cornwall. “It seemed like the obvious solution and it means that the underfloor heating costs virtually nothing to run,” says Robert. “Rainwater is also harvested and then stored in an underground tank, and there are areas of sedumplanted roof space too.”

Building such a technologically advanced new home cost more than initially anticipated, with work grinding to a halt part way through the project when the local water supplier insisted that the waterside platform would have to be removed as it stood in the way of an underwater sewer which was being built at the same time. “This meant that I needed to go back to the planning committee and ask for special dispensation to make a limited number of deliveries by road,” recalls Robert. “It held up the build by around six months, and all the time costs were escalating and the builders were becoming more disgruntled. Even now, the snagging list has only just been completed almost two years after work first began on site, and we’re still experiencing certain problems with the lift.”

Surrounded by Victorian and Edwardian villas in brick and stone, the controversial Riverhouse has undoubtedly made its mark on the town. Standing on the edge of the beautiful estuary, it has been designed from the inside out to take full advantage of its spectacular setting, and only upon entering the house does the extent of this concept become fully apparent. To the casual passer-by the building may appear to be a rather jumbled collection of features, with its flat and curved roofs, skylights, parapets, balconies, terraces, flowing courtyards, planted roofs and external staircases. To its owners, however, Riverhouse is first and foremost a light-filled window onto the water and an everchanging vista of river life.

Extracting Heat from the River

The Riverhouse’s innovative use of a heat pump in the River Dart is explained by Robert Seymour Architects: “We considered using an air heat exchanger, but this wouldn’t have been as efficient as the most prominent resource: the river. Pipes have been sunk into the estuary that pump out water, extract the retained heat with a heat exchanger and then flow the water back into the river again. It works in the same way as a borehole ground-source heat pump that takes heat from the water in the ground, except that it takes it from the Dart instead. Before the water gets to the exchanger it passes through a series of filters to ensure that the system doesn’t get clogged up.

“Though an effective solution, it is not without its drawbacks. A system like this is expensive, around £10,000, and it is also very big. In the Riverhouse, an area has been specifically designed on the patio area to bury it beneath the ground, with access created for annual maintenance. Although the system places low demands on electricity, it does require a constant trickle, and a full-size gas-fired boiler has been installed as a back-up in emergencies. Also, because the Duchy of Cornwall owned the water source, we had to get special permission — a long-drawn-out process.”

Further reading:

• A radical home by the sea
• A coastal renovation
• A self-build by the sea

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