Preparation

The works contract begins with a preparatory phase, which includes the preparation, supervision, approval and rethinking of the corresponding project, and which will necessarily precede the award of the contract.[12]​.

The preparation of the project will normally correspond to the contracting public sector entity. Exceptionally, the preparation of the project may be carried out by the contracting company itself. Such an assumption is contemplated for situations of great technical difficulty,[13]​ and implies the need for the Administration to present a preliminary project to which the project prepared by the contractor will be adjusted.[14]​.

The content of the project is described in detail by the Public Sector Contracts Law (report, plans, technical specifications, budget, work plan, references for the layout, as well as a health and safety study),[15] something that does not prevent the introduction of a flexible regime in which some element can be dispensed with as long as the documentation is sufficient to define and execute the works. In any case, Group A works contracts (new establishment, renovation, major repair) whose amount exceeds €350,000 are excluded from this flexible regime.[16]​.

Finally, the project must include all the studies and reports that are necessary to define the object of the contract. Unless it is not possible due to the nature of the works, it will be mandatory to include a geotechnical study of the land on which the work is going to be carried out.[17]​.

The request for a report from the corresponding supervisory office or unit will be mandatory for works with an amount equal to or greater than €350,000, and for works that affect the stability, safety or watertightness of the property. In other cases, the report request will be optional.[18]​.

The report will verify that the project respects the general provisions and technical regulations applicable to the work in question, and may give rise to the corresponding liability. Given its nature, the report will precede the approval of the project.[18]​.

The rethinking of the work project consists of verifying its geometric reality and the availability of the land necessary for its normal execution. The rethinking will occur after the approval of the project, and before the processing of the contracting file.[19]​.

In this way, the project will be incorporated into the contracting file when the corresponding rethinking has been carried out.[20]​.

Execution[21]​

The execution of the work will be carried out in accordance with the specific administrative requirements, the project and the instructions of the Optional Director of the works and the person responsible for the contract.[22]​.

The Public Sector Contracts Law includes within the section on execution, various provisions on the burden of risk and payment for the work. On the one hand, the deterioration of the work due to force majeure will be suffered by the Administration.[23]​ On the other hand, reference is made to the payments on account for the works that are carried out monthly, for the preparatory operations;[24]​ also mentioning the case of flat-rate works with a fixed price.[25]​.

Modification

The modification of the contract, by the Administration, may result in an increase in the units of the contract. If such an increase is included in the project, the modification will be mandatory for the contractor.[26]​ If it is not included in the project, the Administration will set the prices, and the contractor may refuse. In such case, the Administration will proceed by its own means, or by contracting the increase with another contractor.[27]​.

The modification of the contract may also consist of the reduction or elimination of units, something that does not give rise to any right of compensation in favor of the contractor.[26]​.

Finally, the Law also raises the possibility of a modification occurring by decision of the Optional Director, prior authorization from the contracting body. To this end, a procedure is proposed to be processed urgently that eventually leads to a modification of the project, as well as the approval of the additional expenses it entails.[28]​.

Compliance

Regarding compliance with the works contract, the Law establishes the regime for its reception, guarantee and liability for hidden defects.

After completing the work, the reception ceremony will take place, which will be attended by the person responsible for the work (if any), the Administration's professional, the professional in charge of directing the works and the contractor.[29]​.

The Administration's practitioner may consider them received or declare that they are not ready to be received, depending on the status of the work and its subjection to the requirements provided for in the contract. In the event that the works are considered received, the corresponding minutes will be drawn up, thus beginning the guarantee period.[30]​.

Within the fifteen days prior to the expiration of the guarantee period, the optional director of the work will issue a report on the status of the works. If said report is approved, the guarantee disappears, and with it, the contractor's responsibility. If it is denied, instructions will be given to the contractor to proceed with the corresponding repairs and an eventual extension of the warranty period.[31]​.

Finally, the contractor's responsibility, beyond the warranty period, covers hidden defects that may appear in the work within a period of 15 years.[32]​ After this period, the contractor will see his eventual liability completely extinguished.[33]​.

Resolution

The Contract Law establishes specific causes for termination of the works contract, to which must be added the generic causes for termination of contracts, contained in article 206, and which are common to all public sector contracting "Public sector contracting (Spain)").

As specific causes, we must point out the delay in verifying the stakeout; the suspension of the initiation of works for a period of more than six months by the Administration; the withdrawal or suspension of the works for a period of more than eight months agreed by the Administration; material errors that may be contained in the project or budget prepared by the Administration that affect the budget of the work by at least 20%; modifications to the contract, which together imply alterations of 20% of the original contract price, or represent a substantial alteration of the initial project.[34]​.

The effects of such resolution involve the verification, measurement and settlement of the works carried out, with the corresponding balance established, in favor or against the contractor.[35]​ Likewise, a series of percentages on the price are established as compensation to the contractor for termination of the contract attributable to the Administration.[36]​.

• - Public sector procurement (Spain) "Public sector procurement (Spain)").

• - Administrative contract (Spain) "Administrative contract (Spain)").

• - Work project.