A green roof provides additional thermal benefits over and above the roof insulation. The thermal mass will deliver additional insulation value in winter and summer, reducing heating and cooling (air conditioning) costs.  

Plenty of studies have demonstrated the actual benefits, though it is worth bearing in mind that these cannot be included in thermal calculations due to continued variations in moisture content levels throughout the year. 

Green roofs reduce noise pollution into or out of a building, eradicating the ‘drumming’ sound during rainfall.

The mass a green roof provides above the roofing system provides acoustic properties to the building; airborne noise is further reduced after planting. 

A green roof can make a significant contribution to the points scored in a BREEAM assessment.  Points can be accrued under a variety of headings including POL5, LE4, LE5, LE6 to name but a few.  

With increasing constraint demand for green roofs being part of planning legislation, Local Authority planning departments tend to look favourably at developments that include green roofs, even if they don’t specifically require it as a condition.   

The UK is yet to reach the position of some European Countries – some German regions allow for an increased building footprint and Basel in Switzerland requires green roofs on all new construction.  Green roofs are required within the London Plan and in other regional planning guidelines. 

Green roofs can be used to provide areas to grow food, similar to an allotment, thereby reducing the ecological footprint of an urban area and supporting the production of local, sustainable produce. 

Green roofs change the roofscape of the built environment, taking away dark coloured roof surfaces and replacing them with natural colours that change with the seasons: greens, reds, browns etc. This replacement of the ‘concrete jungle’ with a vista that replicates nature has significant visual, environmental and health benefits and can help blend a building into its natural environment, particularly in rural settings. 

Established plants capture and store carbon dioxide. Studies in the USA indicate that once established 50m² of extensive sedum green roof will capture roughly the same amount of carbon as a broad leaf tree. 

Green roofs both detain and retain rainfall (precipitation) at the point of impact, mitigating flood risk by reducing water loads on drainage systems (SuDS). Quality of water runoff is also improved by the removal of heavy metals and pollutants, bringing benefit to rivers and watercourses. For more attenuation than a green roof can provide, or that can be accommodated on the ground, a blue roof is an option, designed so that attenuation is actively incorporated.