Score - Sustainable Construction in Rural and Fragile Areas for Energy efficiency

Guidelines for integrated territorial planning

The new thermal regulation requires to improve the performance of the invoclure of building. In the mediteranean area, the envoclure should be optimized to take into account at the same time insulation and inertia. So, the choice of materials, thickness and system should be done on the basis of dynamical thermal modelization.

During the reetrofiting of old buildings, insulation of all the parts of invoclure must be considered : roof, external walls, floors and change of windows.

Insulation of floors is not systematic in our climatic region. The decision will depend of the nature of materials, exposition, but also according to the balance between winter and summer comfort.

For the insulation of external walls, three main options exist : interior thermal insulation, exterior thermal insulation and distributed thermal insulation. This last one is usually not used for reetrofiting.

All work on the involucre improves the thermal comfort of the building while it reduces its energy consumption.

The interior insulation has the advantage of present "hot walls". The close presence of the insulator coated with a facing generally low effusivity parment induces a temperature of inner surface very close to that of the ambient air. The radiative heat exchange between the living and the walls is almost zero: no sensation of cold as can be felt close to an uninsulated wall or single-glazed window. Winter comfort is assured.

Improving comfort and the objective of reducing energy consumption require to replace the exterior joinery by performing ones equipped with double-glazing reinforced thermal insulation themselves mounted on a chassis and fitted with low conductive gasket sealing.

The exterior insulation achieves both an objective of energy efficiency and of completely renovate the exterior of the building.

The installation of insulation on the exterior of the existing walls results in the almost complete cancellation of "thermal bridges" (places of weakness through which heat from the building continues to escape despite the presence of insulators).

Improving energy causes an immediate drop in consumption, thus reducing resource consumption

Reductions in cascade: Improving the energetic functioning of the building reduces energy needs immediately so the consumption of resources, therefore the energy bill.

Beyond these operating costs is also the charge of equipment that is reduced. Indeed, the building properly insulated and rewarding the best solar resources in its windows require a heating system less powerful, smaller and easier to accommodate. The stock of fuel will also be reduced and require less space. Cumulative savings are far from trivial!

A significant reduction of environmental impact is obtained by using plant materials as wood fiber or hemp wool for insulation, wood from local resources for joinery.

Further isolate is consistent with achieving effective ventilation: we must avoid that good air tightness and sound insulation of buildings become the source of sanitary nuisances caused by excess moisture. The air must be regularly renewed.

Facilities must meet the requirements of each building type and are codified by the thermal regulations in strengths as well as the departmental health regulations in force.

Improving energy reduces significantly the cost of expenses paid by residents of housing or by user communities.

This point is particularly sensitive when it comes to housing intended for people with a low income: excess loads can lead these people to fuel poverty they are not familiar with moderate loads. This is a way to anticipate social difficulties. An important advantage of the external insulation is to maintain the activity (housing or service) in the building during construction.

Isolate from the outside keeps their living rooms all useful.

On the other hand, the cost differential between internal and external insulation is significantly reduces and even can be reversed when interior insulation requires itself full reconstruction of power grids and / or distribution of heating but also finishing work associates.

Despite the many benefits of insulation and the insulation from the outside in particular, certain challenges remain.

The exterior insulation, often interesting in terms of energy, required to dress the walls by plaster or siding (wood siding, fiber cement, metal ...). In a historical context that is not always desirable.

The choice of Interior insulation increases thermal bridges: limit for design must include the insulation of all walls in continuity, there including floors between level and interior walls according to their nature.

The exterior insulation corresponds to certain uses: building used for permanently, eg housing ; exterior walls of a limited thickness: about old buildings with walls of 80 cm should be very hot to "warm up" the exterior walls and enjoy their inertia: it is not always interesting. However it is always conducive to summer comfort.

Technical difficulties of installation / implementation  :

- The interior insulation is a common technic and well understood by companies.

- The exterior insulation has a few technical points of attention, less mastered by businesses : basement, instalation of shutters, windows singular points, the building must have an overhang enough to allow the installation of the insulation Difficulties in the context of local production :

The exterior insulation, in France, is a practice still uncommon in rural areas. Masons do not control, the work must be asked of facaders.

They have not yet used to use green insulation (wood fiber ...) and we must therefore insist, or even seek diligently companies willing to undertake this work.

Indication for the Bio-construction Action Plan

In France, the “Plan bâtiment Grenelle” sets the objectives for energy efficiency in building sector. The performance of involucre is, combined with systems, the key of reduction of consumptions in buildings. The “Plan bâtiment Grenelle” consists of several actions as follows :

action 1 :

Deepen devices using thermal renovation of habitat:

- Cumulative tax credit for sustainable development and “EcoPrêt à taux zéro”

- Extension of “EcoPrêt à taux zéro” to unions condominium

Action 2 :

Reliable Energy Performance Diagnostics (DPE):

- Improvement of the methodology

- Increased transparency

- Strengthening the qualification and control of diagnosticians

Action 3 :

Strengthen the program "Living Better":

- Support for energy suppliers to exit the modest household from fuel poverty

- Increasing the bonus "Living Better"

Action 4 :

Automate the assignment of social tariffs for gas and electricity

Action 5 :

Extend the eco-housing loan (eco-PLS) for social landlords

Action 6 :

Launch a study to promote the sale of low energy consumption property

Action 7 :

Study explicit energy criteria in the texts on decency in public housing

Action 10 :

Launch a public information campaign on the energy performance of equipment (integrated

institutional campaigns ADEME)

Accelerate the consideration of energy efficiency in public procurement

Action 1: Strengthen networks of public procurers existing and extended to areas not covered

Action 2: Start a major plan of public procurement "energetic performance "

Possible criteria for MED bio-housing quality certificate

Number of certificate already exists and considers performance of involucre. “Labélisation BBC Effinergie”, “Passiv’Hauss”, “Minergie”, … all these certificates set performances for the involucre.

Case studies

Montaulieu district – redevelopment of the meeting room

Mazan community hall

Offices of the CRIEPPAM

Case studies

• Temple de Ste Euphémie
• Logements communaux d’Eygalayes

Download PDF (France language)