With very large properties either side, the basement could not be excavated and constructed in the traditional manner. As a result, the perimeter of the basement firstly saw the installation of sheet piles, 80 metres in total, in order to support the ground and neighbouring houses. The Piling was carried out by specialist piling contractor, who worked with Beautiful Basements design and construction teams to install these piles 10 metres into the ground

  • Drilling for piles to be inserted to the ground
  • Pile drilling to support neighbouring houses
  • Sheet piles being driven into the ground
  • Sheet piles linked together to hold back land, neighbouring property and the excavation
  • Inserting piles to support houses in close proximity
  • Piling driven deep into the ground to support the banks of the excavation
  • Perimeter of excavation formed in sheet piling
  • Concrete beams to prevent neighbours' gardens collapsing
  • Bracing for concrete support beams
  • Concrete support beam with steel reinforcing upstands
  • Reinforcing for ring beam
  • Tops of sheet piles connected into a ring beam with steel reinforcing
  • Ring beam being formed around entire basement perimeter
  • Ring beam being set out
  • Ring beam shuttering ready for concrete
  • Ring beam concreted and stripped of shuttters. Comnplex design with multiple level changes
  • Concrete ring beam
  • First layer of excavation taking place after ring beam links all cheet piles
  • Exposed internal face of sheet piling under ring beam, all retaining the earth behind
  • Excavation done in two, 3m stages
  • Changes in levels throughout basement
  • First layer of excavation complete at 3m deep from the top of the ring beam
  • Once at formation a concerete slab is cast to pin the bottoms of the piling in place, securing top & botton
  • Large supports installed to allow second layer of excavation to formation depth
  • Main basement slab reinforcing
  • Main slab with reinforcing, sump and perimeter channels ready for concrete
  • Changing levels at basement floor level
  • Main basement slab concreted
  • Wall reinforicing steel running from slab to the underside of the ground beam, almost 6m in places
  • Reinforcing for the walls following the sheet piling
  • Shuttering & supports for concreting of walls
  • Change in levels in the basement & support for concrete
  • Timber shutters being supported during concrete pouring
  • Basement walls constructed
  • Some walls within the basement are nearly 6m high
  • Internal walls and changes in levels
  • Concrete external walls
  • Walls shuttered and supported prior to being poured
  • Internal wall stop end shuttering
  • 6m high internal walls being cast in concrete
  • Completed internal walls
  • Internal walls
  • Internal walls ready for waterproofing
  • Change in levels from main basement floor level
  • Internal block work in front of waterproofing and perimeter channels
  • Cavity drainage membranes (CDM) on external walls
  • Internal block work walls to carry block and beam floor
  • Block and beams creating "lower ground floor"
  • Swimming pool construction
  • Lower ground floor swimming pool under construction
  • Large swimming pool, the central feature of the basement
  • Swimming pool sitting in the centre of the basement
  • Internal walls on lower ground floor
  • Internal walls & swimming pool
  • Cavity drainage membrane and perimeter channels
  • Internal walls to carry block and beam floor
  • Internal walls
  • Internal walls being built in front of cavity membrane
  • Internal walls
  • Waterproofing linking to sump

Build Method

Once the piling was in place, the challenge of installing 80 metres of reinforced concrete capping beams to the entire perimeter of the basement began. This capping beam was installed prior to the main dig beginning, to restrain the sheet piles from flexing at the top under the pressure of the ground the outside.

Next, the main excavation began, removing some 250 lorries of soils away from the site. The dig had to carried out in two parts, stopping half-way down to formation to install a set of hydraulic rams to the perimeter up against the now exposed piles. These rams, again, provided the additional strength required to ensure the piles did not flex from the middle. Once the hydraulic rams were in situ the dig commenced once again, this time going down to the formation level where the slab could be constructed.

From there a very complex basement was constructed with multiple levels, an elevator shaft, foul pumping stations, garages, patios and a swimming pool, all constructed in reinforced waterproof concrete walls and floor. Finally, the pre-cast concrete ground floor was laid in place to allow the main, above ground build to begin.

Waterproofing Method

Waterproofing for the project was comprised of two systems to comply with 3rd party warranty requirements;

  1. Integral waterproof reinforced concrete walls and floor
  2. Internal cavity drainage membrane, linked to two pumping stations
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Location: Central Birmingham
Completed: 2019