Sustainable building

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This way of designing buildings tries to save costs and bring social well-being to the residents by using the roof to generate renewable shared power, installing gardens on the facade to improve insulation, or sharing industrial-grade electrical appliances.

Circular architecture is this: The developer of a new apartment block creates a common area for installing washing machines. The residents share these appliances, which saves space in their homes. It cuts down on the manufacture of new machines, in other words, the creation of new resources (less leads to more). Joint purchasing make it possible to have a high-priced but very efficient machine, which reduces power and water usage. A place is created in which the residents can get together and socialize, one of the three pillars of sustainable development together with economic growth and caring for the environment.

The circular economy can enter a building through the common laundry room and go up to the rooftop with the creation of a solar community or the installation of a rooftop garden as a natural insulator. These are ideas that are applicable to homes that have already been built and can form part of the plans for new ones, which can handle other sustainable criteria, such as the installation of modular interior walls or the creation of more common spaces, such as a repair workshop equipped with tools. Alfons Ventura, architect and member of the technical department of the GBCe (Green Building Council España), summarized it in this way: “It is a question of retaining the value of resources as long as possible in the economic system and using energy from renewable sources.”

A woman on a rooftop terrace

Rooftop terrace

Landscaped roofs as thermal and acoustic installation

It is necessary to waterproof the roof and install a barrier against the roots and a membrane for drainage. Also needed is an irrigation system, which will vary depending on whether the building is in a rainy or a dry region. It is advisable to plant indigenous specimens or ones adapted to the local climate, which require little water and are resistant to high temperatures.

Alfons Ventura, architect and member of the technical department of the GBCe (Green Building Council España,), highlighted one way of bringing circularity to the installation based on a real case on which he worked: “When demolishing a building to create a new industrial building, the ground was excavated. The soil obtained was used as a substrate for the rooftop garden on a nearby block.” The reuse of a nearby, existing resource. Something unusable became a raw material.


Photovoltaic panels for renewable energy

A solar community is formed when solar panels are installed on the roof to generate renewable energy and share it with the building’s tenants, as well as with neighbors and small businesses in the neighborhood. The only two requirements are that the rooftop has a minimum surface of 250 m² and that the beneficiaries who want to hook up to the community are within a radius of 500 meters. Photovoltaic panels can be installed on a residential block or on other buildings, such as gas stations, schools, or medical centers, both in big cities and in small towns.

Alfonso Flores, strategy manager at Repsol Solmatch, emphasized the advantages of these solar communities. “Part of the electricity received by the consumers comes from the last mile, locally sourced power that is not only cheap but is generated in their town or neighborhood.” In the almost 300 solar communities managed by this company, 15% of the power received by homes comes from solar panels on a nearby building while the rest is 100% renewable energy. Depending on the size of the roof and the hours of sunshine, an average of 80 homes can be hooked up, and no installation or work prior to hook-up is required.


Communal gardens for living together

The rooftop can be used to grow local fruit and vegetables. Although production is not very large, the garden can also serve as a place in which the residents can socialize and it has a pedagogical value for the children. From the organic waste generated in the homes, compost is obtained to fertilize the soil. Ventura the architect emphasized the social and educational aspect (information needs to circulate; knowledge is lost if one does not keep it at home) but he is more in favor of maintaining or promoting the creation of kitchen gardens in the suburbs of cities. Profitable local products.

A playground with swings

Common areas

A water treatment plant for the community

There are various ways of treating gray water (from the bathroom sink and shower) generated by an apartment block. A of biological treatment system using bacteria and aerobic microorganisms allows the organic material to be broken down and transformed. The process takes place in a cylindrical tank. If there is more space, several plants can be installed to treat the water progressively in a process known as phytodepuration. This process recreates the way that wetlands work using artificial rafts populated by floating plants.

After the purification process, the water can be used to water an urban garden or a landscaped roof, or to fill toilet water tanks. The size of the treatment plant depends on the number of homes and is located in a facility room measuring some 10 to 20 square meters. The water no longer travels through the sewers to the treatment plant that serves the entire city but is treated in the same building.


A laundry room for saving power and space

A room equipped with washers and dryers, if there is no space to hang the laundry outside or the area is rainy, makes it possible to reduce the number of electrical appliances, offering the same service with fewer resources. The time that each washing machine operates is greater, which means that the use of an existing asset is optimized. If it breaks down, the community pays for the repairs so that it is less burdensome for the individual. A system may be installed so that each resident pays for the power consumed. The baskets used for both the dirty and clean laundry are kept in this common area, saving space in the homes.


Repair workshop for sharing tools

In this way, there is less need to buy drills, screwdrivers, or wrenches to assemble furniture or carry out electrical installations. The space acts as a repair workshop for electrical or electronic devices. By being communal, relations between the tenants of the building are encouraged, so that one neighbor may ask help from another to repair a lamp or clean an iron clogged with calcium deposits.


Collection point  for proper recycling

This consists of providing several bins in the common repair area for depositing old electrical appliances and electronic devices, and other waste, such as broken light bulbs, worn-out batteries, etc. One small collection point on the property. As city councils schedule collections, it is a question of contacting them so that every so often this waste is removed and processed properly. Another option is for one resident to be responsible for taking the waste to a nearby official collection point every three months.


Children’s playground with recycled items

Urban furniture, such as benches and the equipment in a children’s playground like swings and slides, are manufactured using the chippings obtained by recycling plastic containers. There are companies that offer a 25-year warranty against scratches or splinters and with no need for maintenance. Here, recycling (converting former waste into raw materials) and the durability of the items (having resources retain their value as much as possible) converge.

A woman and boy on a sofa

Inside homes

Modularizable homes for adapting to change

Flexibility for durability. Circular architecture advocates including temporary elements even though they may be used permanently. Movable partition walls can be installed in order to adapt the house to future changes such as the birth of children or the arrival of seniors. This architect points to plasterboard partitions placed above the plot rather than brick interior walls, which are not mobile and leave marks in the earth. For offices, he recommends easily changeable partitions attached with bolts.


Separation of items for recycling

When someone wishes to create a partition in a home, Ventura recommends using dry wall, made of either gypsum or clay, or even industrial elements that are easy to dismantle and can be reused, such as aluminum or wooden partitions. The architect notes another very old construction method, tiles, to be used for tile roofs and with a re-use rate of 80%.


Height of the ceilings to permit different uses

Circular architecture advocates that resources should retain their value as long as possible without needing extensive work or demolition. The architect Ventura advocates designing homes with ceilings higher than the 2.50 meters required by the regulations so that, if, in the future, someone wants to convert the apartment block into offices or retail premises, there are no obstacles to installing specific types of lighting or air conditioning ducts. The power needed to control the climate of the larger spaces is compensated by using proper insulation and efficient heating and air conditioning systems.



Vertical gardens to combat extreme temperatures

The vegetation prevents the wind from coming into contact with the facade in winter, so that the interior takes longer to cool down. When it is hot, the garden stops the sun’s rays from penetrating. The plant cover purifies the air and traps suspended dust.

To install a vertical garden, the building must first be waterproofed and protected from filtration. Some large, sophisticated vertical gardens already exist, like the one at the CaixaForum (Madrid), which is attached to five tubular structures that act as the ground. The roots anchor in the interior, where the irrigation system runs.

There are other facades with gardens formed by panels embedded with already developed vegetation. They are manufactured using plastic and textiles, in which the plants will live and from which they will obtain water. There are also gardens built using plastic containers as flowerpots, all anchored to the wall. The architect specializing in sustainable construction recommends that the flowerpots that hold plants should be replaced easily, if they degrade, without a need to alter the facade or carry out significant construction work.


Recycled materials for reducing the use of raw materials

Circular architecture advocates recycling as much as possible during remodeling or demolition and using new components with a high content of recycled materials. Fiberglass thermal insulation exists that uses up to 70% recycled glass. Boards are also used that act as thermal and acoustic installation and have a large amount of recycled material in them, such as cellulose, cotton with hot-melt fibers, or fiberboard.

Of the raw materials used in construction that are easy to recycle, aluminum, steel, and wood are outstanding examples. Ventura reminds us not to then add toxic or environmentally harmful coatings, such as certain paints or adhesives, which would ruin a good material as far as recycling is concerned.


Publiished in El País