SOA Category OG1

The official OG1 declaratory defines the category as covering the construction, maintenance, and renovation of buildings designed for human activities, complete with structural components, electrical/technological systems, and all types of finishes. In practice, OG1 includes all standard building works such as homes, offices, schools, hospitals, factories, stations, multi‑storey car parks, and similar structures, along with all connected and accessory works.

OG1 plays a major role in the broader economy because it represents the core of the building construction sector—a sector that generates large-scale employment and investment. In recent years, construction has been one of the key drivers behind Italy’s GDP growth, at times accounting for more than one‑quarter of the national increase. In 2023, the construction sector represented around 11% of Italy’s GDP and employed more than 3 million workers. Each OG1 project activates a substantial supply chain—materials, services, logistics, engineering—creating a strong multiplier effect on the local and national economy.

Because OG1 applies to virtually every building type. From homes to high‑rise towers, from schools to hospitals, from industrial facilities to commercial centers—any project involving the construction of a building falls within OG1. This makes OG1 one of the most frequently required categories. Any complex building project (involving structure, systems, and finishes) requires a contractor certified in OG1. In essence, OG1 is the foundation for delivering most of the civil infrastructure that society and the economy rely on daily.

OG1 is often paired with specialist OS categories that cover specific technical components. Large buildings may require OS28 (mechanical/HVAC systems) or OS30 (electrical installations). For historical buildings, OG2 applies. Another related category is OG11 (technological systems), which covers integrated electrical and mechanical systems and often appears in complex procurement procedures. While OG1 represents the core building work, elements such as elevators, special foundations, and artistic finishes may require additional OS qualifications.

Absolutely. OG1 frequently interfaces with multiple categories when a project includes diverse scopes of work. In integrated contracts, OG1 may be the primary category, while OS28 (mechanical systems), OS30 (electrical systems), or OG11 (technological systems) cover the installations. In large or specialized buildings, it is standard practice for an OG1‑qualified contractor to rely on specialist subcontractors for mechanical systems, elevators, special finishes, and other components when the company does not hold those qualifications directly.