Bio Building

Roof garden: costs and benefits


A vegetable garden on the roof it is more than a green roof. It helps to save energy (thanks to the insulating power of the solution) and guarantees a supply of zero-kilometer vegetables to the residents of the building. The property also benefits from an aesthetic point of view (but the garden must be well looked after!) And social relations can also benefit from it.

It is estimated that a vegetable garden on the roof, or alternatively a green roof can save up to 30% of the energy consumed for heating and cooling the building. This is the reason why this architectural solution has been included among those for energy redevelopment that can benefit from 65% tax relief.

How much does it cost to make a vegetable garden on the roof? It depends on what you want. Approximately a square meter of green lawn alone costs about 70 euros finished. If you add some small plants you get to 100-120 euros. With an endowment of shrubs, and here we are really in the refined, the cost comes to around 200 euros.

Let's say that the average cost of a roof garden for a condominium (the ideal is the flat roofs of city buildings) is around 30 thousand euros, which with the above tax deductions can be practically halved. Go from a lawn to a vegetable garden on the roof it's a moment and at that point the benefits are even more.

What are the benefits for the condominium? The first is energy savings, which as we said can reach 30% of the annual expenditure for heating thanks to the best thermal insulation. Another is housing well-being: a vegetable garden on the roof it helps to maintain pleasant temperatures in all seasons of the year: cool in summer and warm in winter.

Yet another very important advantage is linked to the fact that the roof garden increases the lifespan of the waterproofing. In fact, the green layer protects the roof from thermal excursion, UV rays and possible mechanical damage. Finally, the green roof improves sound insulation because it protects against noise (near airports it attenuates the acoustic impact of aircraft).

And the benefits for the environment? If by environment we mean the community, the benefits of a vegetable garden on the roof o a green roof in the city mainly consist in the reduction of carbon dioxide emissions and filtering of atmospheric dust. A roof garden works exactly like any other garden, contributing to the quality of the air.

A further 'public' benefit of rooftop gardens is water retention, which can reach 70-90% of rainfall. The result is the lightening of the discharge into the white water network as well as the possible reuse of waste water, after recovery and filtration.


Video: How Green Roofs Can Help Cities. NPR (October 2020).