annuaire

Environmental functions and benefits

The environmental quality of a building is its ability to satisfy 3 requirements:
-    limit the impact of the building on the external environment,
-    create a comfortable, healthy environment for its users,
-    preserve natural resources by optimising their use.
The
HQE scheme (HQE association) is an approach proposed to building owners and builders encouraging them to make the choices that best meet the needs of "sustainable development" at every stage of a building's life: design, construction, use, adaptation and demolition. It is a voluntary scheme which fixes objectives to be reached (HQE target), but it is part of a political and legislative framework which will become ever more pressing (law on the air and the rational use of energy of 30 December 1996, law on sustainable  land use of 16 June 1999).

For the building owner, this is an excellent lever for promoting a global cost approach that is more economical over the long term. (Source: HQE in the building industry).

The table below summarises the targets met by extensive green roofing compared to conventional roofing.

 

Conventional roof

THEME

HQE TARGET

Green roof

 

mineral surface

THE ENVIRONMENT

integration in a "mineral" environment of vegetated surfaces hosting biodiversity (flora and fauna)

ECO-CONSTRUCTION

Target 1 : Harmonious relationship of the building with its immediate environment

 

 

vegetated surface

 

impermeable surface

 

WATER

Controlled drainage with delayed stormwater  runoff (water retention) and reduction in the volumes of water entering the sewerage system  (by evaporation), filtering of the water with a view to its storage for domestic re-use

ECO-MANAGEMENT

Target: water management

HEALTH

Target 14: water quality

 

 

water-retaining surface

 

SUSTAINABILITY

The green roof build-up provides mechanical, thermal and UV protection, which largely contributes to increasing the life of the waterproofing membrane

ECO-MANAGEMENT

Target 7: Management of maintenance

 

 

UV protection

 

reflection

HYGROTHERMAL FACTORS

humidification of the  ambient air (counters the urban heat island effect caused by the concentration of mineral surfaces in urban areas)

COMFORT

Target 8: Hygrothermal comfort

 

 

absorption

 

reverberation

ACOUSTICS

absorption of exterior noise (reverberation) and improved interior sound insulation (mass effect)

COMFORT

Target 9: acoustic comfort

 

 

insulation

 

inert surface

VISUAL ASPECT
integration into an environment of mineral surfaces of biodiversity (flora and fauna)

COMFORT

Target 10: visual comfort cf.
photo library

 

vegetation

 

accumulation of pollution

THE AIR

absorption of surrounding dust and fixing of CO2 by the plants

HEALTH

Target 13: air quality

 

decontamination