The Director of Work Execution (DEO) is the figure created by the Spanish Building Planning Law (LOE), in its objective of defining the responsibilities of each building agent.

This agent is part of the Project Management,[1]​ along with the Construction Director and the Health and Safety Coordinator.

In accordance with article 13.2 of the LOE, the qualifying academic qualifications to be able to perform this position are:

When the works to be carried out have as their object the construction of buildings for the uses indicated in group a) of section 1 of article 2, the qualifying academic and professional qualification will be that of technical architect. This will also be the qualifying qualification for the works of group b) that were directed by architects. In other cases, the direction of the execution of the work may be carried out indistinctly by professionals with the qualification of architect, technical architect, engineer or technical engineer.

This position is assigned by law some obligations that, according to current methods of contracting and executing works, may be reduced and/or assumed by the builder "Builder (building agent)"), despite the fact that the DEO works directly for the promoter "Promoter (building agent)").

According to the LOE, the DEO should carry out, among other things, verifications of all construction products that are going to be used, as well as order precise trials and tests. In addition, he should direct the material execution, while preparing and signing the partial certifications, which are the monthly invoice that the developer "Promoter (building agent)") pays to the builder "Builder (building agent)").

In the real world of construction, the figure of the DEO is extremely variable depending on the person who holds the position. There are several ways to carry out this position, which normally, logically, depend on the fees that the technical architect receives.

The main task of the DEO is, to put it in a more summarized way, to act as a representative of the promoter, together with the architect, in front of the builder, and ensure that the latter complies with the conditions of the contract between them, as well as ensuring that the monthly invoice that the promoter pays to the builder is appropriate based on the work carried out by the builder during that month, or period stipulated between the two (developer and builder).