26. Every person who carries out construction work or causes if to be carried out and offers the building or structure concerned for sale or exchange is presumed to act as a contractor unless he proves that the work was not carried out in view of sale or exchange.
Every person who commences new construction work within less than one year from the end of the first work undertaken is presumed to act as a contractor for the purposes of this act.
The termination of the work means, for the application of the preceding paragraph, the date on which the structure is ready for the use intended.