There is growing evidence that visual and physical contact with natural greenery provides a range of benefits to people. These include both mental health benefits (such as reduction of stress) and physical health benefits (including cleaner air). Access to green space can bring about direct improvements in a person’s heart rate and blood-pressure, and can aid general well-being.
Work environments within buildings could be improved by green roofs
A Texan study of post-surgery recovery in hospitals demonstrated that recovery was quicker and with less chance of relapse if patients could look out onto green space. A number of American hospitals have subsequently been redesigned to bring these benefits to patients, and have been rewarded with greater patient ‘through-put’.
A roof on the Kanton Hospital in Basel was redesigned 20 years ago by vegetating it, as it was felt that patients in intensive care would benefit from looking out onto this rather than the grey space of before. A few community hospitals in the UK are now being designed with greater consideration of green space provision. The good practice work on hospital design being developed by the Commission for Architecture and the Built Environment (CABE) is likely to support this.
The thermal benefits that green roofs provide may also have indirect benefits for people living or working within the building. This has not been researched, but anecdotal evidence from Germany in the late 1990s is of interest. In a survey of staff absence through sickness at the Bundepost offices in Stuttgart, staff in one building demonstrated significantly lower absences than those in others. The only change in the 4-year period that could be identified was that one of the buildings was given a green roof. This building supported lower staff sickness levels. It is possible that the green roof reduced the fluctuation of daily mean temperatures within the upper levels of the building, and/or the vegetation helped cool and moisturise in-going air near ventilation ducts.
In the past 2-3 years, possibly picking up on the increasing interest in green roofs and the UK government’s interest in green space, developers are increasingly showing green roof space as a component of their new commercial development proposals. The provision especially of accessible green roof space for future workers appears to be gaining currency, and could help off-set the likely constraints of green space provision on the ground.