Grand Designs

It’s not every day that we get asked to design an extension to a penthouse. In fact, not many penthouses can be extended without defying the rules of gravity!

It’s fair to say that the challenges were enormous; it’s an old building, it would remain occupied throughout the construction phase, there were numerous different materials and weather-proofing details.

It was an exciting assignment, but not without a few challenges.

For example, the building was on an exposed cliff-top and we had to design it to withstand storms and high winds coming off Bournemouth Bay and the Purbecks. But at the same time, the ‘construction site’ was the roof itself, so the design also had to use lightweight materials to address concerns over hoisting materials into place and the eventual loading of the building.

The original building pre-dated acoustic or fire regulations, but obviously we needed to comply with the current regulations. And as it is within a conservation area, there were the inevitable planning hiccups; in fact it took several years to obtain planning approval.

There was also the not exactly insignificant problem of a gas main running over the top the building!

Ellis Belk was able to steer its way around all these obstacles. The result is a construction project that caught the attention of Channel 4’s highly popular property programme Grand Designs.

Panoramic views

Many of us dream of a property overlooking the sea – preferably on a cliff-top location. For most of us though the idea remains a dream. However, for our client and owner of the penthouse on top of Tollard Court in Bournemouth’s West Cliff area, the situation was very real. The property had great potential, especially if it could be enlarged to make full use of its wonderful location.

Tollard Court was built as a hotel in the 19th century and still retains many of its original features. However, it has also gained many additions since then, including a huge copper dome, built in the 1920s.

After the war, the hotel was converted into around 40 flats with the fourth floor becoming a modest three-bedroom penthouse. But although this had panoramic views over the sea, behind it was a jumble of flat roofs – plus the dome which by now was only being used to house water tanks.

These flat roofs offered great potential. The penthouse could be stretched out across them to create a substantial and luxurious apartment.

Ellis Belk set to work – it was a project with tremendous scope. We felt there should be a distinct visual break between old and new, so we started with a very modern design featuring a curved roof and plenty of glass. However, Tollard Court is in a conservation area and sadly the planners erred on the side of caution. “So it was back to the drawing board,”.

A decision was made early on in the project that the dome would be one of the main features of the new design. To make the most of the dramatic space it created, the design includes a circular gallery running around the inside reached by a glass spiral staircase. From this you can look down onto the main lounge below.

Here we used 3D modelling software (Autocad ADT) to help understand the complex shapes involved, particularly the spiral staircase design.

The penthouse is up on the fifth floor so we designed the extension around a steel frame with timber studwork in between (drawing on our experience with timber framed housing) so that materials could be easily craned into position or hoisted up without too much concern about weather conditions.

The exposed nature of the site means that the weather has played its part more than usual in the process: We had to ensure the new shell was kept weather-tight. In a storm, the rain coming off the sea can be so heavy that it is driven up the walls instead of down.

Other issues have been the acoustics and fire regulations. Because of the age of the building it’s never before had to comply with building regulations. In fact because of the special case of the penthouse, we had to use the services of an acoustics engineer

Dream home

Highlights of the new extension include an enormous family room which open up onto a sizeable decked terrace with glass balustrading and large motorized rooflights which can be opened up at the touch of a button. These features, together with the centrepiece of the dome and gallery, all work to achieve our aim of an opens, airy ambiance.