With Article 9 of Regional Law No. 8 of June 6, 2025 – in force since June 11, 2025 – Articles 65-bis and 65-ter have been introduced into Regional Law No. 12/2005. These
new provisions regulate the construction of mezzanine floors with the aim of promoting building renovation and urban regeneration, while minimizing land consumption.
The legislation allows the construction of mezzanine floors – defined as accessible horizontal structures obtained by partially inserting a load-bearing element into a closed
space – within individual, existing residential units. These mezzanine may be used for both residential and office purposes.
With its own agenda, the Regional Council instructed the Regional Executive to clarify that the “office” use does not constitute a separate urban planning category, but represents an ancillary use compatible with the residential function, which remains predominant.
From a building regulation perspective, the construction of mezzanines falls under the category of building refurbishment and requires the prior issuance of the appropriate building title.
It is also permitted as an exception to the maximum gross surface area limits set by the current Town Planning Scheme (P.G.T.) and local building codes, provided that:
i. Applicable health and hygiene standards are met;
ii. Minimum height requirements, as set out in Article 65-ter are respected
In particular:
- if the gross floor area of the mezzanine does not exceed 50% of the area at stake, the minimum height between the floor and the underside of the mezzanine, as well as that between the floor of the mezzanine and the finished ceiling of the rooms above, must be at least 2.40 m;
- if the gross floor area of the mezzanine does not exceed 30% of the area at stake, the minimum height, measured using the same criteria, may be reduced to 2.10 m.
Mezzanine construction, being classified as a building refurbishment, is also subject to the applicable building fee.
The full text of the law is available at the following link: Banca dati del Consiglio Regionale della Lombardia