As per your contention, you have to file case against the builder and not against the association. Nothing to do with the association, has association has not build the apartment, builder has build the apartment without maintaing quality. So if you want to take any legal action, you have to take legal action against the builder.
Examine the articles of association of the Society to check if the Association has taken up the responsibilty for maintenance. If they have a provision, then employ the mechanism within the ambit of the Society to ensure that the roof is reparied. You definetly have the option to file a consumer complaint against the Builder as he/she failed to provide the required product to you. For this you will have to establish that the fault was on the part of the Builder with the help of evidence.
Book a phone consultation with a top-rated lawyer on Lawfarm.