If your completion is due next year you have to wait till then (unless you can be sure something is already been bad done, in that case you can start looking for a lawyer)
The Architects and Aparejadores are responsible of a non-defective construction as they have to sign the ‘Certificado Final de Obra’ certifying everything was built in accordance with the project and license and has no apparent defects…
From then, but not before, you have the right to demand and get a full repair.
I can tell you that here, in Asturias, Architects receive an average of 200 claims per year related to building defects (this is the figure I know as an architect lawyer. There are many others directed only against builders I can have no notice of) about a 70 to 80% are settled out of court in an acceptable/satisfactory way for everyone. The rest go to court with an average delay of 8 to 10 months for a final sentence.
The vast majority of times proprietors get the proven defects repaired or economically compensated.
But, and this is extremely important, do not let a bukaroo or kamikaze lawyer to inflate or exaggerate your claim (unfortunately there are some ‘professionals’ very kind on this practice) you will risk a partial sentence and you wont get your legal expenses refunded.