Sustainable architecture, which materials

Knowing which materials to choose for a sustainable architecture, how to recycle them and how to dispose of them are fundamental evaluations for the development of environmentally friendly buildings.

Starting from load-bearing structures to the windows, the materials used must favor energy savings and have a minimal impact on environmental balances.

Recycled and recyclable materials, with high air and water tightness, represent the solution to an increasingly eco-friendly architecture.

Let’s find out what are the materials of sustainable architecture, how to recycle them and why they are the focus of passive houses.

How to recycle the produced materials

How to recycle the produced materials is fundamental in sustainable architecture, which rejects traditional concrete, bricks and roof tiles.

For a totally sustainable home it is necessary to focus on materials:

• ecological;
• recycled;
• cheap.

Widely spread in the United States and in some European countries, with particular emphasis in France, Germany, Netherlands and other areas of northern Europe, sustainable architecture is still struggling to establish itself in Italy, even though the EU is promoting sustainable materials for architecture, such as:

• wood;
• cork;
• straw;
• hemp;
• thermal microporized bricks;
• bio-concrete.

Wood is a renewable material, flexible, resistant and capable of good thermal insulation. It can be combined with cork, especially in the construction of doors and windows. Cork, excellent thermal and acoustic insulator, is a breathable material, also used for glue free panels.

Among the sustainable materials, the straw is a valid soundproofing, breathable one, able to increase the resistance of wooden structures. When pressed into small blocks, it is fire resistant.

Hemp is also one of the materials increasingly used in sustainable architecture. Combined with lime, it improves wood performance.

The thermal microporized bricks are thermal and acoustic insulators, breathable, obtained with green materials, such as wood sawdust or rice husk, which however cannot be considered totally sustainable, due to the complex processing required to obtain it.

Finally, among the most used materials, we must mention bio-concrete, a material capable of regenerating itself thanks to its own bacteria.

Especially in recent decades the practice of recycling construction waste has been widely promoted, in Italy, by a building policy directed towards some fundamental principles:

• recovery of abandoned buildings;
• awareness of hydrogeological risk;
• responsible use of resources;
• containment of landfill activities.

In addition to the recovery of abandoned building areas, we observe an environmental policy that is increasingly attentive to the exploitation of quarries and all the resources of the territory. This environmental policy needs to limit the landfill use for non-recyclable waste.

With the Legislative Decree of 5 th February 1997 No. 22, known as Ronchi Decree, aligned with the directives of the European Union, companies operating in the demolition sector are required to fill out forms aimed to the identification of the waste, with a view for reducing production and making the most of recycling.

In the field of architecture, these goals mean the optimization of the design, construction and management phases of a sustainable building.

It is necessary to think about the whole life cycle of the building. The demolition must be seen as the initial phase of the recovery process to which waste sorting enhances the product.

To facilitate the concatenation of the three phases, today Europe adopts the CER/2002 code, which classifies waste with codes useful for the compilation of the so – called MUD (Environmental declaration model), which composes a sort of waste loading and unloading balance in the year.

A law regulates the disposal of building materials based on:

• maximum quantity that can be disposed of;
• origin of waste materials;
• characteristics of the waste and conditions of use;
• certificate of non-hazardous nature of the recovered materials;
• transformation, treatment and recycling after verification by the involved Municipality.

Passive houses, what they are

Passive houses fully meet the needs of sustainable architecture.

Built of recycled, recyclable and highly efficient materials, they are based on two goals:

• energy efficiency;
• salubrity for people.

Above all, the second is the cardinal principle that results in energy saving.

Among its peculiarities we include:

• thermal insulation of the building envelope;
• controlled mechanical ventilation.

In fact, the passive house aims at bioclimatic architecture. The latter, thanks to natural elements such as proper exposure to sun and winds, minimizes the use of polluting artificial heating and cooling systems.

The passive house enjoys excellent exposure to sunlight and a controlled mechanical ventilation system for the renewal of the air in the rooms, avoiding dispersion.

The passive house must be able to use in the best possible way all that nature provides. The heat of the sun is optimized thanks to the proximity of natural shade (trees) and through the installation of glass walls, thermal windows and shading systems, such as sunshades, shutters, masharabie.

The combination of these factors, together with the use of suitable construction materials, guarantees a high resistance to thermal agents and the healthiest solution with a low environmental impact.

So the passive house is the result of an evolved sustainable architecture. The internal comfort is as high as in other traditional homes, without taking advantage of artificial air conditioning systems.