As of January 1st 2015, for all the Building, Industry & Artisan Enterprises the employer must pay the additional contribution for the enrollment to the PREVEDI Fund, for every WORKER and EMPLOYEE.   

Basically, the Building Employer must pay, for every hired worker, the INPS and CASSA EDILE contributions as well as those of the PREVEDI Fund. 

The payment of the monthly contribution is mandatory for the entire period during which the employee is subjected to the “CCNL Edili Industria ed Artigianato”. The amount of each employee will be calculated on the basis of the level and the indicated ordinary hours.
The PREVEDI contribution  will appear as a simple information notice on the paycheck, but it will not directly modify the amount of the salary; it will, however, appear as an added increase for part of the INPS entry (10%) and for the remaining part of the CASSA EDILE on the F24 Form, through which it can be paid.