Mahaudières’ renovation at Rezé (44)

réhabilitation MahaudièresProject owner : lnh
General contractor : ALTEREA
Localization : Rezé (44)
Period : 2013 – 2015
Type of buildings : housings
Number of functional units : 2 buildings / 120 collective dwellings and 13 individual housings
Area : 9 732 m²
Cost : 2 920 000 €HT – 21 955€ HT/housing
Energy gain : before : 280 kWhEP/m² – after : 88 kWhEP/m² = -69% (label E to C)


In 2010, La Nantaise d’Habitations (LNH) has defined an energy renovation’s program with a goal of removing E, F and G ranks of its estate. The 2010-2016’s objective is the following :

  • Renovate 130 housings per year for a total cost of 3,5 millions euros per year

At the end of 2014, more than 600 housings had been renovated or were in course of building site, and changed to C rank. For 2015 and the following years, the priority was to handle the residences ranked D with a Diagnostic of Energy Performance (DPE) > 190kw, so 700 housings.

Mahaudières’ renovation has been fallen within the Energy Renovation Program of LNH, in order to remove E, F and G ranks of its estate. An innovative approach of consultation with the tenants has been launched, so that they can take part of the building site program. Those has to cost savings but also improve the comfort.

ALTEREA had been chosen by LNH to run this renovation. The company, with Espacecité, had animated too, different workshops with the tenants in order to co-work the building site program.


  • Improve the energy performance (C rank at minimum)
  • Reduce the heating system’s spendings of the tenants
  • Improve the comfort of the housings

A building site program co-worked with the tenants

1 – Common locals and the exteriors of the buildings

  • Creation of a heating substation connected to the urban network
  • Creation of a collective distribution for the heating system and ECS (hot water for sanitary use), for all collective dwellings and individual housings
  • Insulation of roof-terraces and low floors opened to the outside
  • Installation of an hygro controlled mechanic ventilation A (replacement of chambers, air extract units and air inlets)
  • External thermal insulation of 4 individual houses with roof-terrace
  • Restoration of entrances (replacements of the grounds, installation of false acoustic ceilings and strengthening of the doors’ security)

2 – Private premises

  • Transformation of loggias into living rooms in 62 housings : installation of a dividing wall, internal insulation of walls of the loggia opened to outside, installation of a woodworked dividing wall between the loggia and kitchen, restoration of all finishes of the loggias and living room adjoinings, creation of false ceilings (with a load-carryied wood framing on 5,5m) in cathedral loggias

  • Fifting by recovering of compact PVC floorings’ coating in all rooms of the housings

3 – Layout of the outsides (made by MAP-Paysagistes, cost of the works : 541 000€ HT)

  • Add value to the main entrance:
    • Requalification of the planted place
    • Creation of a pedestrian area with levels
    • Planting of common spaces with public domain


  • Redefine housings’ limits of the downstairs:
    • Creation of private terraces, delimited by plantations
    • Renovation of walls and fences
    • Closing of the balcony passageways on the main garden


  • Transform the Charlie Chaplin’s place into “garden place”:
    • Creation of planted containers on substation’s slab


  • Layout of the garden at the center of the residence:
    • Possible crossing according 3 accesses
    • Creation of a playground
    • Creation of shared gardens


An operation realized with the support of


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