Building on Tronchet street Paris 9ème (75)


Philippe Pumain

Progress/Delivery date
Preliminary studies ongoing

Surface area
1 327 m²

Construction cost
€5M excluding tax (value date 2021)

Scope of services

  • Structure
  • Electricity
  • Fluids
  • Construction economics
  • Thermal
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Extensive refurbishment of an office building.
The 19th century Directoire-style building includes:

  • Six superstructure levels buildt on a basement level,
  • A covered courtyard at the rear of the building,
  • A south-facing courtyard,
  • Another courtyard to the east.

Technical characteristics

Demolition of existing staircases and floors.
Creation of an all-level stairwell as part of the superstructure.
Creation of a steel deck floor aligned with the openings in the service staircase.
Creation of a staircase from the ground floor to the basement and its foundations under the low floor of the basement flush with the courtyard (excavation - underpinning).
Reinforcing the floors with an 8cm reinforced concrete slab, connected to the existing sound wooden joists.
Replacement of damaged timber frames.
Reconstruction of the floors of the 1st, 5th & 6th floors.
Reconstruction of certain floor areas on the 1st/2nd/3rd and 4th floors.
Reconstruction of the rear courtyard roof to create an accessible flat roof at first floor level, with new foundations under the new load-bearing structures.
Regulation fire protection for structures and obtaining regulatory fire stability.
Removal and reconstruction of the roof structure & roofing with the inclusion of dormer windows on the street side, roof windows on the courtyard side and a mechanical room on the courtyard side.
Reconstruction of a concrete slab floor with thermal insulation on the lower floor of the basement and covered courtyard.
Local reinforcement of the ground using solid injections to limit settlement caused by the new loads.
Ventilation of offices and meeting rooms provided by a dual-flow system with energy recovery from extracted air.

Environmental characteristics

Thermal regulations: Existing thermal regulations.
Heating and cooling provided by a reversible heat pump.