Green roofs in additon to the aesthetic-functional applications have a number of advantages over conventional roofs :
- They are decreasing "heat island" effect. During summer days concrete and metal on buildings can reach temperatures up to 70°C, while green roof can reduce this by 40°C.
- The building with a green roof creates its micro-climate, so building is cooler in summer and warmer in winter. This means less energy is needed for air conditioning
- It absorbs pollution and particles from air which can be very useful in the city.
- It absorbs rainfall and reduces the load of water on sewage system during rain and melting snow. City authorities also benefit from these systems, since they don't need to invest in expansion of new sewerage systems.
- Green roofs also reduce noise levels by about 50 dB (which is level of murmur of people in the restaurant)
- They offer an attractive alternative to standard roofs
- It increases environmental consciousness of people
- They provide natural environment for birds, insects and small animals
- Green roof protects roof insulation material from UV radiation and reduces daily temperature fluctuations. According to some tests performed, this extends roofs lifetime by double
- Real estates with such architectural features have bigger market value. Its likely that invested funds for a green roof will repay itself just by selling the property
Green roofs also have their disadvantages:
- Initial investment is usually higher than conventional roof systems
- Weight of the green roof increases the load on the building and should be cafefully considered
- Green roofs should be regularily maintained, depending on type of green roof.
- Extensive green roofs need to be maintained every 6 months to a year, depending on the plants. Intensive green roof needs to be mainteined every month or two.
- Care must be taken of any diseases that can easily spread and infect other plants