Those who put their labor upon or furnish materials for a piece of work undertaken by the contractor have an action against the owner up to the amount owing from the latter to the contractor at the time the claim is made. However, the following shall not prejudice the laborers, employees and furnishers of materials:
(1) Payments made by the owner to the contractor before they are due;
(2) Renunciation by the contractor of any amount due him from the owner.
This article is subject to the provisions of special laws. (1597a)