What is A Green Roof?

What is A Green Roof?

A green roof is a roofing system that uses plant life for cover instead of or in addition to, traditional cover materials. In simple words, it is growing vegetation on your roof. This idea is not new and can be traced back to the Sixties. It has however gained recent popularity due to it’s environmental benefits and the ability to reduce heating and cooling bills.

There are 3 types of green roofs:

– Intensive Green Roofs. These are green roofs that are able to accommodate large plants such as trees or a full lawn. This kind of green roof needs a significant soil depth and lots of maintenance. The level of maintenance needed for this type of roof is comparable to that of a large garden or park.

– Semi-intensive green roof. This type uses plants of moderate size and will require a little less maintenance compared to the intensive type.

– Extensive green roof – Of all the green roof types, this one is the most convenient. It features a growing medium covered with vegetation. The kind of vegetation grown does not need large depths of growing medium so the medium is kept thin. This kind of rooftop requires very little maintenance and care.

The Benefits Of Having A Green Roof

There are several benefits of having a green rooftop on your building. They include:

1. Energy efficiency – Green roofs offer insulation to the building, reducing heat loss and heat absorption by the building. This helps reduce the cost of moderating temperatures inside the building as roofs will lose a lot less of the building’s heat during the winter and let in less heat during summer.

2. Green roofs increase your roofs durability – Green roofs protect the waterproofing membrane on your roof from large temperature fluctuations that would otherwise cause tearing and ultraviolet radiation that degrades the membrane. This will in effect expand the lifespan of your roof by 2 to 3 times.
3. Noise reduction – A green roof will block out noise from the outside world making the inside of the building ideal for work or rest. An extensive green roof (the thinnest kind) will block outside noise by up to 40 decibels with an intensive one going up to 56 decibels.

In addition to these, you shall have benefited the environment by:

  • reducing sewer overflow
  • reducing the impact of carbon monoxide
  • neutralizing the acid rain effect and much more.

Disadvantages Of Having A Green Roof

It’s not all rosy with the green roofs. There are a few issues but they don’t outweigh the benefits. They include:

  1. High installation cost – The initial cost of installation is quite steep and especially so if you hire the services of a professional. The savings you will make later will however more than make up for the initial cost.
  2. Added weight to the roof – The additional weight of the live roof might pose a potential issue and especially so if your building cannot handle it. This will require structural modifications which cost money.
  3. Pesticide leakage – Studies have shown that it is possible for pesticides to runoff from green roofs and infiltrate ground water. Thick membranes should be used to curb this.

If you decide to install a green roof on your building’s rooftop, the following considerations should be made:

  • The system’s drainage
  • The purpose the roof is to serve
  • Visual requirements
  • The kind of access required
  • The load bearing capacity of your structure
  • Your budget
  • And finally the maintenance budget.
Authored by: Pete Anderson

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