The family has grown and you need an extra bedroom? The house you live in has become too small and you need more space? The answer to these questions is usually to look for a new home, but this is not always the ideal choice. Indeed, leaving your home, strategically chosen because it is close to services or because it is located in the same neighborhood as the family of origin or because it is in a green environment or with particular comforts, can generate a lot of doubts and stress. Instead of committing to a move, with all the consequences of the case, you can opt for a home extension. How does it work? Consider that many regions of Italy have joined the "Housing Plan": a special measure that allows the volumetric increase of housing according to parameters defined, precisely, at regional level. A number of provisions therefore encourage private investment to enlarge houses rather than build one from scratch.


To this possibility, we add that in some regions, the extension of the house with a green construction is encouraged and rewarded with a larger extension volume compared to traditional construction. For the sake of clarity, the extension of the house can be subject to several choices. These are based on both the needs of the inhabitants and local, municipal and regional regulations. After checking with the technical office of the municipality about the possibility of extending the building, the choice of construction method comes. The fastest type is the extension of the house with prefabricated modules, which allows to start and close the construction site in a few weeks. The choice of prefabricated buildings in green construction is particularly advantageous because it allows the energy requalification of the entire house, which translates into considerable savings on future bills. Green building includes a series of construction techniques and materials aimed at having the least possible impact on the environment, among which the use of wood stands out.


Particularly in the case of an elevated building, the choice of a wooden extension also allows to fix two or more floors in height. Indeed, the wooden superstructure allows to avoid excessive loads on the pre-existing structure, without compromising its stability. The extension of a masonry house with a wooden prefabricated is not only possible, but also recommended when a traditional intervention would not be possible for structural reasons.


If, therefore, you opt for a wooden extension, the choice of the supplier will be necessary. Among the historical companies in the world of prefabricated wooden houses, there is Positive Space, an Italian company with roots in Germany, born from the know-how of RENSCH-HAUS, a company known throughout Europe for its specific experience in the field of ecological construction with low energy consumption. The Positive Space wooden extensions, whether elevated or horizontal, include the energy requalification of the entire building, the inclusion of the latest generation systems and the total respect of the parameters that make the house anti-seismic. In essence, everything you need to make your new home a true Positive Space.


The law only requires the use of an architect for a house extension when the total surface of the house exceeds a certain threshold. However, the knowledge of the architect often allows to avoid mistakes and increase the potential of the house as a whole. This professional gives advice on the distribution and configuration of the rooms, on the materials to be preferred, on the type of extension according to the architecture and the existing ground, etc. He also helps with the preparation of administrative procedures and can, if the owner wishes, coordinate the various trades and follow the work until the handover of the keys. At first, his business and commercial relations guarantee you savings on the purchase of materials. Secondly, his experience allows him to manage the site with a master hand and to respect the deadlines of the work. This option entails additional fees corresponding to a percentage of the amount of the work. They rarely exceed 12% but can be a little higher if the architect benefits from a good notoriety. Another strong point linked to the fact of being supported by a professional: in case of disagreement with the administration, the architect can intervene and make accelerate the procedure of the building permit or the preliminary declaration of work. In the same way, he can negotiate with the Architect of the Buildings of France to obtain an agreement. To have him at his side reassures and allows to reduce the delays. The architect then plays fully his role of accompaniment.


The building permit is the administrative document that provides the relevant bodies with all the elements necessary to verify a construction project and compliance with the town planning rules of the municipality. The documents to be provided include a graphic document showing the insertion of the construction in the landscape, a photograph of the land and the surrounding environment, concise plans of the construction and the various forms to be filled in according to the nature of the project. A building permit is required for extensions with a floor area or footprint greater than 20 m² or 40 m² in urban areas (U zones). A building permit is also required for extensions with a floor area or footprint greater than 20 m², less than 40 m² and bringing the total area of the house to 150 m² or more (the 170 m² threshold has been lowered to 150 m²). In this last situation, the use of an architect becomes essential. Furthermore, if your project involves real estate restoration operations, if the work affects buildings with the title of "historic monument" or if some of the work modifies the structure of the building while changing its purpose, a building permit is also required. Make sure your file is complete to avoid it being returned to you! This would lengthen the time needed to obtain an answer from the administration.


The preliminary declaration of works is an official device which governs all the works not subject to a building permit. It is simpler to fill in and requires fewer documents than a building permit. However, this formality requires rigor and method to be taken seriously and accepted by the competent services. A preliminary declaration of works is required in different cases. Firstly, it is compulsory for extensions with a floor area or a footprint greater than 5 m² and less than or equal to 20 m². It is required for any extension of a house with a floor area or a footprint less than or equal to 40 m² and not bringing the total area of the house to 150 m² in urban areas and based on a planning document. The rules are the same for extensions bringing the living area to 150 m² and located in a non-classified area. You will also have to file a preliminary declaration of works at the town hall if you wish to change the destination of the existing building, if you plan to include in your extension works the restoration of the facades or if you wish to modify the external aspect of a building. The other obligation to fill in a preliminary declaration of works is when a modification of the volume of a building appears after the piercing of an external wall. Finally, the prior declaration of works becomes indispensable for certain particular cases: for example when the works take place inside buildings in protected sectors and if these same works do not modify the original structure or volumes. This mandatory document generally receives a response from the administration within one month.


The Local Urban Plan of the municipality sets the urban planning rules and provides essential information concerning the construction, extension or renovation of a house. The architectural prescriptions must be respected to the letter in order for the building permit or the preliminary declaration of works to be accepted by the town planning services of the commune. Since 2000, the PLU has replaced the POS (Plan d'Occupation des Sols) and remains the only official document to be consulted before carrying out any house extension project. It takes into account the environmental obligations imposed by the State in the framework of the policy on sustainable development and energy transition. It imposes certain standards and only authorizes materials and colors that respect the municipality's urbanization project. Building and public works professionals are obliged to be familiar with it in order to be able to pass on the various information to their clients. The obligations of the PLU are necessarily reflected in the plans and estimates. Individuals wishing to extend their house without hiring professionals must consult the PLU at the town hall and note the elements that may modify their construction. Note that the municipalities have a certain latitude and depending on their geographical area may or may not require a building permit above a certain area.


Non-compliance with the PLU, non-conformity of the work, lack of building permit or lack of declaration of work lead to sanctions. In case of non-compliance with the urban planning rules, the mayor has several alternatives. For any situation of non-compliance, the sanctions incurred are mainly administrative. Please note: compliance must be certified by the DAACT form upon completion of the work. In the case of unauthorized work, the mayor may decide to stop the work or to demolish the newly built part. He can also forbid the connection to the networks. The offender can be fined up to 300 000 €. It is however possible to file a regularization permit to avoid the application of the demolition action. In the case of concealed works (such as a cellar or attic development of more than 40 m²), the sanctions can be administrative, civil, fiscal and even penal. Sworn agents regularly check new installations and draw up a report for the municipality. These agents have three years to intervene. The owner cannot avoid this visit. If he obstructs it, he risks a fine of more than 3 000 € and a prison sentence.

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