Project Type
Basement Conversion
Duration
20 weeks
Project Value
£145,000
The Challenge
Camden's Basement Development SPD imposes strict controls on basement conversions in Hampstead, including requirements for a basement impact assessment covering hydrology, structural impact on neighbouring properties, and the effects on trees. A large London plane tree in the front garden was subject to a TPO and its root system extended beneath the proposed excavation zone.
Our Solution
We commissioned a full basement impact assessment including a hydrology report and arborist's root investigation. The structural design was amended to use a contiguous piled retaining wall, which minimised excavation impact on the tree roots. A Type B tanked waterproofing system with drainage channels was specified for permanent damp exclusion. Camden approved the application in 12 weeks following the assessment submission.
Results
- ✓Camden planning approval in 12 weeks — basement impact assessment approved
- ✓TPO tree root system protected — arborist confirmed no root damage
- ✓Contiguous pile retaining wall — 42 piles installed
- ✓Type B tanked basement — independently inspected and certified
- ✓80m² of new liveable basement space created
- ✓Home gym with Technogym equipment and mirrored walls
- ✓Cinema room with 4K projection and acoustic treatment
Key Features
- ✓Camden basement impact assessment and planning approval
- ✓Contiguous piled retaining wall — TPO tree protected
- ✓Type B tanked waterproofing with cavity drain backup
- ✓Natural light wells to front elevation
- ✓Home gym — sprung floor, mirrored walls, Technogym equipment
- ✓Cinema room — 4K laser projector, acoustic panels, tiered seating
Specification
| Item | Specification |
|---|---|
| Retaining structure | Contiguous bored pile wall, 350mm diameter, reinforced concrete infill |
| Waterproofing | Sika Bituseal tanked system (Type B), cavity drain backup, sump and pump |
| Light wells | Bespoke galvanised steel light wells with toughened glass covers, drain to soakaway |
| Gym floor | Rephouse Sportmaster sprung rubber, 8mm, in dark charcoal |
| Cinema room AV | Epson EH-LS12000B 4K laser projector, 120" Grandview screen, Sonos Arc surround |
| Cinema acoustic treatment | Vicoustic Cinema Round Premium panels, perforated MDF battened walls |
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