Roof tiles as first choice for sustainable building

The Urban Heat Island (UHI) effect, which affects urban and metropolitan areas, especially in the Mediterranean, has long been known and is scientifically documented. This occurs when an urban or metropolitan area is significantly warmer than outlying areas at any given time.

The heat island effect can manifest in two ways:

1. superficial: the rise in surface temperature that occurs due to exposure to solar radiation (depending on the degree of absorption, the properties of the materials, etc.)

2. atmospheric: a temperature rise of +2°- +3° (although scientists estimate that this will rise to +5° by 2050) in urban areas compared with surrounding rural areas, particularly noticeable during the night when surfaces release the heat absorbed during the day.

This is due to various factors that are specific to each individual place:

• the urban configuration (depending on the level of urban density and presence of high-rise buildings in the area)

• solar exposure

• typical weather conditions (the amount of wind, rainfall, etc.)

• the presence and extent of urban green spaces

• the concentration of the main business activities

• the quality of the materials that characterise the same.

The latter factors can play a key role in improving the situation since they react to natural phenomena (humidity, air, irradiation, etc.) and can condition the local microclimate. Scientists are conducting a great deal of research into these phenomena and are focusing in particular on monitoring events and devising strategies aimed at containing emissions and mitigating the effects. The initial goal is to hold the increase in the global average temperature to well below 2°C above pre-industrial levels, as established in the Paris Agreement of 2015, and to reach the year 2050 with net greenhouse gas emissions close to zero.

We frequently hear talk of resilience, understood as the capacity to adapt to change. When talking about systems (ecological and urban), this refers to the system's capacity to repair itself and return to its initial state following disruptive action and the consequent modification of its original state.

Looking at cities today, such a goal seems difficult to achieve. It is, however, certainly possible to avoid worsening the situation and for this reason, many Italian cities have adopted programmes aimed at:

• updating plans and measures for reducing greenhouse gas emissions

• increasing the production and use of renewables

• devising energy-saving strategies for public and private buildings

• rethinking mobility from a sustainability perspective

• supporting the circular economy

• monitoring and measuring changes

• setting up early-warning systems and emergency plans to manage risks and reduce the risk exposure of the population

• assessing the correlations between changes, health and health costs

• focusing on green urban spaces

• investing in urban development, the proper management and use of the soil, water resources, buildings and infrastructure.

Resilience needs therefore to be planned: a principle that is valid when referring to the quality of cities, their parts and buildings.

In the cities, the strategies to be adopted should essentially aim to reduce waterproofing and new land consumption, control rainwater runoff and monitor urban drainage and the water network, with adequate infrastructure, and lead to the creation of green systems and networks and the widespread construction of public and private squares, boulevards and gardens.