Green Roofs Dorset

Dating as far back to the days of their Viking ancestors the Scandinavians have been ‘greening’ the roofs of their homes. So why, here in England with our ideal growing climate are green roofs not a more common spectacle? Here at Low Carbon Energy Centre in Dorset we believe that the simple answer is that people are yet to fully understand their benefits?

Benefits of a green roof?                                                          

  Increases the useable space of a building

  Visually attractive

  Benefits local biodiversity

  Improves fire protection of the building

  Helps filter pollutants and CO2 out of the air

  Helps with local planning policy in urban areas

  Improves water quality by filtering out pollutants

  Improved management of rainfall (storm water runoff)

  Creates diverse habitats encouraging local wildlife & insects

  Protects the building against the effect of rapid temperature changes

  Significantly increases the buildings thermal and acoustic value

What exactly is a green roof?

Put simply a green roof is one that is partially or completely covered with vegetation.

Green roofs generally fall into two distinct categories, intensive and extensive, this generally relates to the level of maintenance they require.                                                                                                                                                                              

Intensive roofs

Intensive green roofs (commonly known as roof gardens) are composed of relatively deep substrates and can therefore support a wide range of plant life including trees. They are generally designed as recreational spaces often with varying degrees of hard and soft landscaping. Consequently, intensive roof systems have greater loadings and require specific structural support.

They were often labelled as rather traditional in their design, simply reproducing landscapes found at ground level e.g. lawns, decking, paving and water features. However, with the modern day thinking of landscape architects we are starting to see revolutionary designs which are both visually and environmentally exciting.

Extensive roofs

Extensive green roofs have generated the greatest public interest in recent years. In contrast to intensive roof systems they are considerably more lightweight in design, requiring little or no structural support and can be incorporated into both new build applications and ‘retro-fitted’ onto existing roofs. They are composed of multiple lightweight layers of free-draining material (max 150mm in depth) that support low-growing, hardy, drought-tolerant vegetation (known as sedum blankets).

Bio-diverse roofs

Bio-diverse roofs (or brown roofs) are another exciting option proving increasingly popular nowadays due to people’s greater awareness of conservation issues. They share many of the benefits of a green roof but differ in that they are designed to meet specific biodiversity objectives often replicating specific habitats to encourage rare or threatened species.

Maintenance of Green Roofs?

A frequently asked question regarding the maintenance of a green roof is “how do I get my lawn mower up there?” For health and safety reasons we wouldn’t encourage this, so short of investing in a goat there is unfortunately an element of pruning and weeding. However, for any green fingered enthusiast out there it’s just like any other form of gardening but at a slightly higher altitude.

Obviously if you are looking to invite the village over for a game of bowls on your roof it may require more than just a yearly trim. The widely popular Wild flower mats on the other hand generally only require cutting back once or twice a year and can provide year round colour with a carefully chosen planting scheme.

For those of you however with less of a head for heights the low growing sedum blankets are an ideal alternative. Whilst they still provide instant greening they   require little or no maintenance as they are specially adapted to cope with the extreme roof top environments of high winds, hot sun, drought and winter cold.

Conversely, intensive roofs can involve substantial input of resources, not only watering and weeding but also, irrigation and fertilization.

Whether you live in a country cottage, a town house or caravan, whether your roof is pitched or flat, north or south facing our friendly team of experts at Low Carbon Energy Centre in Wimborne, Dorset can offer design solutions to soften the appearance of those drab concrete tiles or lifeless bitumen felt and give your roof a new lease of life!