Cubierta extensiva e intensiva; descubre por qué esta clasificación no encaja en climas cálidos.
En nuestro artículo principal sobre cubiertas vegetales y sus beneficios, ya explicamos que aunque se clasifican en cubiertas extensivas y cubiertas intensivas, a nosotros no nos encaja muy bien esta definición para climas como el de España.
In this article we are going to explain why we don’t quite fit these definitions.
The first thing to say is that, although in Spain there are several very different climates; Mediterranean, steppe… etc. the climate in almost all of Spain has nothing to do with the oceanic climate.
But before we continue, let’s clarify what is an intensive cover and what is an extensive cover.
- What are they?
- How do they differ?
- How should you really classify a green roof?
Traditionally, roofs have been divided into extensive and intensive:
What is an extensive roof?
Extensive roofs are roofs where we do not have any type of maintenance, where we simply place a substrate (normally a substrate of very little thickness) on top of the roof .
In other words, once the roof is in place, it has to function on its own.
What is an intensive roof?
An intensive roof would have more to do with having a garden on a roof.
That is to say, having a series of plants that require maintenance, watering, fertilising, pruning, etc.
This very general classification has so far been assumed to be the main classification for green roofs. And it seems that in the end it is either extensive or intensive cover.
What happens then in places like Alicante, Madrid, Barcelona or Malaga where the climate does not allow extensive cover but we want low maintenance or no maintenance at all?
If we make an extensive cover what will surely happen is that the cover will die.
We must be clear that a cover without vegetation does not provide the same as one with vegetation. But if, in order to have vegetation, we have to irrigate, then we are no longer talking about extensive cover.
For example, if in Alicante or Madrid we build a roof without irrigation, given the rainfall in these two areas in summer, it will become ugly during the summer months.
The plants will end up dying in many places while some areas will remain dry although alive.
All this leads us to the conclusion that in warm or continental plateau climates we cannot make extensive covers as they are done in France or Germany, because we have to water them if we want them to be beautiful.
So from SingularGreen, we want to reformulate this usual classification a bit because currently ‘extensive’ green roofs are being made in Spain with irrigation and fertilisation and this, strictly speaking, is not an extensive roof.
How do we decide whether it is an extensive or an intensive cover?
When building a green roof, what we have to think about is the use we are going to give it.
If we want a green roof to have an effect on the temperature of the building, on biodiversity, but we are not going to see this roof (i.e. we don’t care if it is green or dry at certain times of the year), we can go for what is considered an extensive roof.
In this case we will install a series of plants, for example grasses, which are adapted to this type of climate, need little substrate and do not require watering.
This will mean that in spring the roof will be green but then in summer it will look dry, although as we can’t see it, we don’t mind.
What happens is that often green roofs also have an aesthetic component and we need the roof to look nice.
So if we need the roof to be green all year round, we need to design a system that is as low maintenance as possible.
We will need to have a remote control system to control the irrigation and warn us if it stops watering and it is also advisable to have a fertiliser system, because as we are still working with very little substrate, it needs fertiliser from time to time.
This would theoretically be an extensive cover, because of the amount of substrate and the type of vegetation, but in reality it is an extensive cover garden.
Of course, we cannot consider this mixed cover as an intensive cover either, because it does not require the same maintenance as this other type of cover.
If we want a vegetable garden on the roof or if we want a garden with aromatic plants, this requires a different type of substrate, a different type of irrigation and a different type of maintenance.
In conclusion, another type of roof.
Conclusions Extensive cover
When we are faced with a roof project, the first thing we must ask ourselves is what the roof is needed for and what we want it to be like.
It will not be the same as a lawn to lie on or simply a half-timbered roof that requires minimal irrigation.
Classifying canopies as extensive or intensive is complicated because classifying a rosemary as extensive or intensive doesn’t quite work.
So this classification of extensive and intensive covers is very diluted, and that is why at SingularGreen we prefer to talk about uses.
