Recall that a 50% tax advantage is entitled to:
— for interventions to build garages or appurtenant parking spaces, even under common ownership;
— for the purchase of already built garages and appurtenant parking spaces
.
In both cases, the deduction is calculated on the expenses for the construction of garages or parking spaces which, in case of purchase, must be demonstrated by a certificate issued by the seller.
If the sale is preceded by a compromise, the deduction is due only if the preliminary purchase is registered and if the appurtenant connection with the residential building emerges from it. Any down payments made before the registration of the act are not eligible for the deduction
.
The deduction for the construction or purchase of garages and parking spaces follows the same rules as the renovation bonus: this is a personal income tax deduction, to be divided into ten annual installments of the same amount, limited to private residential properties.
Source