Holland Park, London

This is the latest project we have designed for a developer client that we have worked with over a ten year period. The house is grade two listed and has suffered various unsympathetic and technically flawed conversions in its recent history. Whilst our clients are intent on appropriately renovating and restoring the original house, they are keen to maximise the development potential of the property. To this end the project team has created a vast basement space to the rear of the property, incorporating a swimming pool, gym, sauna, steam room, and parking for six cars. Above this will be a new landscaped garden in sympathy with the original period of the house. The scale and proximity of the subterranean space has created a number of technical problems, especially in relation to the listed building.

To create the seven metre deep basement we have driven 15 metre long steel sheet piles into the ground, 100 millimetres away from the rear wall, and installed ground anchors beneath the house. Over 90 concrete bored piles have also been used around the perimeter to allow the basement excavation to proceed.The completed basement will have a total volume of more than 3,000 cubic metres, one could park at least ten Double Deck Buses inside it. We suspect that this will be one of the largest basements within a private house in London. The project is due for completion at the end of 2008.

Architect 23 Architecture