Green roofs, also sometimes referred to as living roofs or rooftop gardens, are an alternative roofing option in which the roof of a building is transformed into a garden. A rubber sealant is applied as the bottom layer, and soil and irrigation installations are placed on top, creating a living component of the roof. Because of this unique method of fabrication, green roofs provide a distinct set of benefits and drawbacks to the building they are installed on. Understanding what green roofs have to offer can help you decide if they are the right choice for your home.

The Advantages of Green Roofs

Insulation Properties: The thick layer of organic matter which grows on a green roof helps trap cold air within your home during the summer (and the inverse during the winter), as well as helping to reduce the exterior noise that enters your home.

Reduced Drainage Load: Because the plants used on a green roof will absorb rainwater as it falls, the amount of water that actually drains off of your roof and through your gutter system is significantly reduced. This can help prevent wear on your gutters, and also reduce the amount of water that has to drain into your yard, reducing the chance of basement flooding and other drainage issues.

Fire Safety: Because of their increased water retention, green roofs can help reduce the chance of a fire occurring, or can act as a barrier that can slow the spread of a fire, allowing the occupants of your home to get out safely.

The Disadvantages of Green Roofs

Increased Leak Potential: Though green roofs reduce the amount of water which drains off of your roof, the roots of the plants which hold on to this water can sometimes penetrate the rubber membrane of the roof, allowing water to leak into your home. This can lead to water damage and mold growth, which can be expensive and time consuming to fix. While this risk can be mitigated by inspecting the plants for problematic growth, this represents increased maintenance costs.

Snow Retention: In a similar vein to the above downside, the organic matter of plant life on your roof (even though it will not be alive) can lead to increased snow retention in the winter months. This can place a dangerous strain on the structural supports of your roof, and can require you to clean the snow off your roof after heavy snowfalls, adding to maintenance costs.

With these pros and cons in mind, work with a residential roofing contractor to decide if a green roof would work for your home.