building materials

Complete guide to types, properties and uses

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Why choosing building materials is crucial

Every structural and finishing element of a building is subject to mechanical, thermal, hygrometric and chemical stresses. The correct selection of building materials It allows you to optimize the performance of the work based on the climatic context, the type of use and the current regulations - from the Technical Standards for Construction (NTC 2018) to the European Directive on the Energy Efficiency of Buildings (EPBD).

Factors that guide the choice of building materials include:

Mechanical resistance and structural stability: ability to withstand static and dynamic loads without permanent deformations.
Thermohygrometric behavior: thermal conductivity (λ), heat capacity and vapor permeability.
Durability and weather resistance: resistance to freeze-thaw cycles, humidity, salinity and UV radiation.
Sustainability: embodied carbon emissions, recyclability and local availability.
Cost and ease of processing: economic impact and compatibility with available construction technologies.

Building materials: concrete and cement

Il concrete It is the most widely used construction material in the world. It is made by mixing Portland cement (or other hydraulic binders), aggregates (sand and gravel), water, and, increasingly, chemical additives and mineral additives.

Main types

Ordinary concrete (CLS). Used for foundations, floors, and elevated structures. The characteristic strength (fck) typically ranges from 20 to 45 MPa.

High-performance concrete (HPC) and ultra-high-performance concrete (UHPC). With fck above 60 MPa and up to 200 MPa, they are used in bridges, skyscrapers and prefabricated structures subject to high stresses.

Fiber-reinforced concrete (FRC)The addition of metal, polypropylene, or glass fibers improves ductility and resistance to post-peak cracking.

Lightweight concrete. Made with porous aggregates (expanded clay, perlite) to reduce structural weight and improve thermal insulation.

Special cements

In construction, different types of cement standardized by UNI EN 197-1 are used:

CEM I (pure Portland): for ordinary structures and prefabricated buildings.
CEM II (Portland composite): with the addition of slag, pozzolana or limestone, reduces the heat of hydration.
CEM III (blast furnace): high resistance to sulphates, ideal for aggressive environments.
CEM IV (pozzolanic) and CEM V (composite): hybrid solutions for specialized applications.

Bricks: tradition and innovation

The bricks — bricks, blocks and tiles — are among the building materials The oldest and still irreplaceable in many contexts. Produced by firing clay at temperatures between 900°C and 1050°C, they combine mechanical strength, thermal inertia, and breathability.

The main categories of bricks for construction include:

Solid and semi-solid bricks: for load-bearing walls, fences and exposed finishes.
Perforated and honeycomb blocks: with a perforation percentage of up to 55%, they optimize the ratio between mass and insulation.
Porous blocks: the addition of wood flour or polystyrene during kneading creates a highly porous microstructure, reaching thermal conductivity (λ) values of up to 0,09 W/m·K.
Tiles and slabs: elements for brick-concrete floors, in combination with reinforced concrete beams or joists.

Structural steel and steel reinforcement

The structural steel It is the backbone of high-performance construction: skyscrapers, industrial warehouses, bridges and long-span structures benefit from its extremely high specific strength (strength/weight ratio).

In construction practice, two main uses of steel can be distinguished:

Reinforcing steel (rods and welded mesh, EN 10080): with yield strength fyk of 450-500 MPa, it works with concrete to withstand tensile stresses.
Rolled structural steel (HEA, HEB, IPE, UPN, EN 10025 profiles): for framed structures, lattice girders and mixed steel-concrete structures.
Stainless steel: used in aggressive environments (coastal areas, swimming pools, food industry) due to its high resistance to corrosion.

A critical factor in designing with steel is fire protection, regulated by Eurocode 3: bare profiles rapidly lose strength above 500°C, so cladding with intumescent materials or shotcrete is necessary.

Structural wood and engineered wood materials

Wood is the building material natural par excellence, currently at the centre of a true renaissance thanks to engineering technologies that are multiplying its structural applications.

The main engineered wood products (engineered wood) for construction are:

Glued laminated timber (GL, EN 14080): long-span beams and arches, with adjustable resistance and rigidity.
Cross-Laminated Timber (CLT): cross-laminated plywood panels, used for load-bearing walls, floors and solid wood building envelopes.
LVL (Laminated Veneer Lumber): parallel glued veneer sheets, ideal for large cross-section beams.
OSB and structural plywood panels: for wind bracing, floors and permanent formwork.

Structural wood is a building materials It's carbon-negative during plant growth and offers excellent thermal and acoustic performance. However, it requires adequate protection from humidity, pests, and fire—the latter can be addressed through structural sizing with a residual cross-section or fireproofing treatments.

Building materials: thermal and acoustic insulation

The energy efficiency of buildings depends largely on the quality of the insulating materialsItalian legislation (Legislative Decree 192/2005 and subsequent amendments and additions) and the EPBD Directive impose increasingly stringent thermal transmittance (U) limit values.

Comparison of the main insulating materials for construction

Material	λ (W/m K)	Typical thickness	Main applications
EPS (expanded polystyrene)	0,030–0,038	8–16 cm	Thermal insulation, roofing, foundations
XPS (extruded polystyrene)	0,029–0,038	6–12 cm	Floors, foundations, wetlands
Rock wool / glass wool	0,030–0,040	10–20 cm	Walls, roofs, sound insulation
Polyurethane (PUR/PIR)	0,022–0,028	5–10 cm	Sandwich panels, flat roofs
Wood fiber	0,038–0,050	12–24 cm	Wooden walls, ventilated roofs
Airgel	0,012–0,018	2–5 cm	Limited technical spaces, retrofit

Sustainable and innovative building materials

The construction industry is responsible for approximately 40% of global energy consumption and 36% of CO₂ emissions. For this reason, the building materials sustainable are acquiring an increasingly central role in contemporary design.

Environmentally friendly materials

Concrete with recycled aggregates (RAC): partially or totally replaces virgin aggregates with selected demolition materials.
Electric Arc Furnace (EAF) Steel: produced with over 80% scrap, it reduces emissions compared to the integrated coke supply chain by approximately 70%.
Bricks with secondary raw materials: industrial waste (fly ash, sludge) partially replace virgin clay.
Natural hydraulic lime (NHL): low clinker binder, compatible with historic structures and green building constructions.

Innovative frontier materials

Photocatalytic concrete: Thanks to the addition of titanium dioxide (TiO₂), it degrades organic pollutants and NOₓ present in the air due to the action of sunlight.

Self-healing concrete: Capsules of bacteria or chemical agents activate in the presence of water, independently sealing cracks and extending the life of the structure.

Building Integrated Photovoltaic (BIPV): PV modules replace facade or roofing elements, transforming the envelope into an energy generator.

ETFE (ethylene-tetrafluoroethylene) membranes: Transparent and ultra-light cushions for covering large surfaces, with a light transmittance greater than 90% and a weight 1% compared to equivalent glass.

Floors and walls

I floors and coverings They play a role that goes far beyond aesthetics: they determine the comfort, safety, and durability of spaces. The choice depends on the intended use, expected traffic, and the humidity conditions of the environment.

Il porcelain stoneware It is the most widely used material today, thanks to its water absorption of less than 0,5% (BIa classification, EN 14411), high abrasion resistance (PEI classes I–V), and the almost total absence of extraordinary maintenance. For wet environments, it is essential to check the slip resistance class R (R10–R13 is recommended according to DIN 51130).

I natural stone materials — marble, granite, travertine, slate — offer aesthetic uniqueness and longevity, but require attention to porosity: granite is naturally compact and stain-resistant, while marble and travertine require periodic water-repellent impregnation.

Il parquet It combines aesthetic warmth and excellent technical performance. Solid wood can be re-sanded over time but is sensitive to moisture; pre-finished multilayer wood is more stable and compatible with underfloor heating.

Le epoxy and polyurethane resins They guarantee seamless, joint-free surfaces with high mechanical and chemical resistance. The main limitation is sensitivity to residual moisture in the substrate: before installation, the screed moisture content should not exceed 2–2,5%.

When choosing, you must also consider theacoustic impact: in residential buildings subject to the Prime Ministerial Decree of 12/5/1997, resilient systems under the floating screed (cork, polyethylene) are often necessary to comply with impact noise limits.

Wall paintings

Le wall paintings They influence wall breathability, moisture protection, indoor air quality, and surface durability. The technical parameters to be evaluated in the data sheet are hiding power (classes 1–4, EN 13300), vapor permeability (Sd), water resistance (w1–w3), and washing resistance.

Le mineral paints — made with lime and potassium silicates — are the most breathable (Sd < 0,01 m), alkaline, and naturally antibacterial. Silicate-based coatings react chemically with the substrate, creating a permanent bond that lasts more than 20 years. They are the ideal choice for the restoration of listed historic buildings.

Le acrylic paints Water-repellent coatings are the most common in residential applications. Silicone-coated or fluorinated coatings add water repellency and UV resistance, with an outdoor lifespan of up to 15–25 years. vinyl, less expensive, are only suitable for dry interiors due to their lower resistance to humidity.

Among the functional products, the following stand out: anti-mold paints (with active biocides, essential in humid environments), the intumescent (which in case of fire expand a protective layer, classified REI 30–120) and the heat-insulating with hollow microspheres, whose effect, however, does not replace an external insulation system.

Finally, we look to the future of wall paints. Researchers at Nanyang Technological University in Singapore have developed a porous cementitious paint that cools buildings Combining solar reflection, heat radiation, and evaporative cooling, it mimics the mechanism of human sweating. After two years of testing in tropical climates, the results are remarkable: air conditioning consumption reduced by up to 40% and internal temperatures lowered by an average of 2°C.

Regardless of the product, the preparation of the support The following are crucial: wall humidity below 8%, removal of loose particles, suitable primer, and filling of cracks. Adhering to the application conditions indicated in the data sheet—temperature between +5°C and +35°C, relative humidity below 80%—is just as important as the quality of the paint chosen.

How to choose building materials for every project

There is no single building material universally optimal: the selection must be the result of a multi-criteria evaluation that takes into account specific project needs.

An effective methodological approach includes the following steps:

Analysis of the intended use: residential, commercial, industrial or infrastructural determines the environmental exposure classes and minimum performance levels.
Assessment of the climatic and seismic context: the seismic zone (DM 17/01/2018) and the local hygrometric conditions influence the structural choice and the stratigraphy of the envelope.
Life Cycle Assessment (LCA): quantifies environmental impacts from raw material extraction to disposal, according to the ISO 14040 standard.
Life Cycle Costing (LCC) Analysis: consider not only the initial cost but also maintenance, replacement and disposal.
Check local availability: favoring building materials available from short supply chains reduces transportation, costs, and environmental impact.

Conclusions

Mastery of the properties and applications of building materials It is a fundamental skill for anyone working in the construction sector. From reinforced concrete to CLT panels, from aerogel insulation to ETFE membranes, the panorama of building materials The range of products available today is richer and more diverse than ever. Knowing how to read and interpret technical data sheets, certifications, and environmental product declarations (EPDs) allows you to make informed choices that combine structural performance, living comfort, sustainability, and long-term durability.

Innovation in building materials It's progressing at a rapid pace: staying up-to-date on new solutions—through technical standards, university research, and industry trade shows like Saie in Bologna or BAU in Munich—is key to designing and building with an eye to the future.