Vegetable or green covers. Advantages and disadvantages of the green roof.
Something that we can already perceive are the green roofs or vegetables. Many new buildings and a few rehabilitated, a vegetal layer of green colors appears that covers their roofs - in some cases on walls, as we can see in this article about the vertical garden on a wall - as a vegetal proposal to the traditional architectural approach.
It is to be appreciated in front of those dark, gray cities, in which we normally live, and that, in some cases, it is difficult to find a green blanket where to breathe a little purer air.
A ground cover Well planned, it provides character to the building as well as a multitude of benefits if we work consistently.
The green roofs They are considered as a precious asset, a new space for recreation and leisure, a new grain of sand that contributes to improving the lung of the city and its visualization, without detracting from the technical properties of improvement that it brings us to our property.
What is a green roof?
The green cover It is a constructive installation that has a vegetal mantle over a thickness of earth or substrate and is specially conceived to obtain environmental benefits.
The vegetation coverage can be total or partial, and does not refer to the typical roofs with plant pots, but to construction technologies whose intention is to improve the habitat or save energy consumption in the building, it is definitive, technologies that meet a ecological function.
Green roofs are a good example of multifunctional urban design
It should be noted that the living roof It is the one that has been valued and is used by the neighbors for various activities, it should not be confused with a landscaped roof that has a more environmental objective.
Types of green roofs
Knowing what you want to achieve with the renovation of the roof is essential, since it will influence the design, construction or the level of maintenance required, which is very important and will include economically in the long term.
In the following diagram we can see the types of green roofs What can we do on a zotea:
The green roofs design It is aimed at meeting the needs of the majority of users, and this aspect should be considered in the option adopted. Always remembering that ecological roofs they bring tangible environmental benefit to cities.
How to run a green roof project?
It must be taken into account that the property of a rooftop can belong to different people (In a building, horizontal property that ultimately belongs to everyone) or legal entities. Depending on the modality, the decision-making process to carry out a rehabilitation of a roof will be less or more complex.
In the following scheme we can perceive the main steps for the execution of a green roof roughly:
What should we take into account if we want to build a green roof?
To design a green roof it is important to understand the characteristics of the site, but there are many more. Below is a summary of the parameters necessary to analyze the technical and environmental conditions before how to make a green roof.
| What data do we need to start analyzing the viability of green roofs? |
| Weather information |
| Maximum and minimum temperatures |
| Annual rainfall |
| Wind variations |
| Influence of weather factors depending on the height of the building |
| Local environmental conditions |
| Possible fire hazard |
| Urban air pollution |
| Analysis of local vegetation |
| Risks regarding the effects of vegetation pests |
| Structural loads |
| Maximum deck load capacity |
| Point loads estimation |
| Fixed loads estimation |
| Drainage network |
| Drainage points |
| Prevention to avoid traffic jams in the event of torrential rains |
| Roof surface and shape |
| Useful surface |
| Available space for the development of vegetation |
| Roof slope |
| Water collection and storage possibilities |
| Quality of the existing work: state of waterproofing, walls, security … |
| Access |
| Accessibility for people (elderly people, people in wheelchairs …) |
| Access to raise and upload construction materials, substrate … |
| Access for maintenance, safety fixings, lifelines |
| Access to the facilities: water points, electricity … |
In truth when we execute a green roof we are reproducing nature including all its filtering features.
Let us remember that this construction system is included in 12 ecological guidelines for sustainable cities that we should consider in the future of modern urbanism. And an example of a green cover We can see it in the following video:
Although we are used to seeing a natural grassy surface, it is not always accurate. There are alternatives that require little maintenance if we use synthetic garden grass combined with real plants. The results are good and we will need less water, although, obviously, it will not be so beautiful, but a ecological cover more sustainable.
We are going to list the advantages and disadvantages that green roofs offer us to be able to decide if it is a valid option for any of our projects:
Advantages of green roofs:
- Improves the urban climate; Reduction of urban warming.
- Reduction of pollution: They work as an environmental filter so we could say that it is a ecological roof.
- Increases water retention: They are capable of retaining up to 80% of precipitation. Drainage systems work better, water flows more consistently.
- Improves protection against noise. Green roofs are excellent noise attenuators, especially at low frequencies. An extensive ceiling can reduce up to 40 dB, while an intensive one can reduce up to 50 dB.
- Energy saving. Efficient thermal insulation is achieved.
- Extension of the useful life of the waterproofing as it is protected from outside temperatures.
- Provides new Parkland in the city that needs green lungs to improve air quality (See also the long article on home gardens).
- Improvement of the visualization and leisure spaces of the city.
- Vegetation can fulfill several functions in the vegetation cover; Shade, wind protection, fire resistance, biodiversity, shade, perspiration … etc.
Disadvantages of green roofs:
- The green roofs they have higher structural requirements, especially the intensive ones. So technically it is an effort that translates into an economic increase in spending.
- Some existing buildings cannot be modified because they would not support the weight of the soil and vegetation.
- Maintenance costs may be higher depending on the type of roof.
- Water proofing is also important: installing a suitable waterproof and root-proof layer can increase the cost of installation.
- Specialized labor force in the execution.
- The problems derived from humidity or leaks in buildings due to poor execution can lead to a high economic cost.
Characteristics of green roof components:
I add the link for consultation from HERE to a Prezi presentation … «Green roofs and geotextiles» by Jordi Blanquet, ageneric conceptual framework of green roof design Because of its clarity in the concepts, we believe that it is of interest to the users of the portal.
Their execution will depend on the constructive solution that we have proposed for the new building or the rehabilitation. At present there are already a multitude of systems on the market to be able to act coherently before the realization of a cover with the expected needs. We wanted to make a compilation of guides and manuals to have a base regarding a topic as interesting as this:
Manuals or guides on green roofs or vegetables:
- Technical Recommendations for Green Roof Projects… HERE. (Very interesting)
- Green roofs. Planning execution and practical advice (Gernot Minke) … HERE.
- Roof planning guide green (ZINCO) … Check from HERE.
- Facades and roofs manual green
- Green roofs. A sustainable strategy (Open Engineering) … HERE.
- An approach to green roofs … HERE.
- Construction of green roofs (Buenos Aires) … HERE.
- Green roofs in the Southern Cone … HERE.
- Construction section details of ecological roofs… HERE.
- Essay with vegetal architecture … HERE.
- Green Roof HandBook … HERE. (Simple but clear, in English)
- Green Roof Manual … HERE.
We remind you that we have a specialized search engine for PDF documents in the architecture and engineering sector. You can find many extra documents!
Web of interest (There is a world on this topic, but as an example):
- Urban landscaping … HERE.
- Alicanteforestal … HERE. (So much green roofs such as vertical gardens. Technical documentation of vertical gardens, technical details, plans, etc … very good!)
- Urbanarbolism…. HERE. (Both green roofs and vertical gardens and technical documentation of green roofs according to the system, very good)
- Sustainable Urban Drainage … HERE.
Points of interest:
- Bioclimatic design manual …HERE.
- Green covers vs. white ones … HERE.
- Bioclimatic design in house facades … HERE.
- The form of architecture encouraged by the wind and the sun …HERE.
- Urban design, more than 30 manuals …HERE.
- Biosustainable or sustainable architecture (22 Documents …HERE)
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