Roles

Project manager, architect and site director in Spain: who does what

Francisco González Mellado · Aug 4, 2026 · 7 min read

It is a fair question, and it comes up in almost every first meeting: if I am already paying an architect and a site director, what does a project manager add? It deserves a straight answer.

The confusion is understandable. The Spanish system has several technical roles with similar-sounding names, and they do not map neatly onto the British or Irish model. Let us separate them.

The roles defined by law

The Ley de Ordenación de la Edificación (LOE) sets out who is who on a building site and what each is liable for. Three of these roles are technical and mandatory on a house:

The designer — proyectista

Produces the project documents: layout, structure, services, materials and regulatory compliance. For a house, this is an architect. Their responsibility is that the design is correct, buildable and legal.

The site director — director de obra

Directs the works so that what gets built matches the approved design and the licence. Usually the same architect who produced the design. Resolves technical queries, approves design changes and signs the completion certificate.

The execution director — director de ejecución

Normally a arquitecto técnico, roughly equivalent to a building surveyor or clerk of works. Controls the physical execution: verifies materials, checks quantities, runs quality control and signs the monthly valuations of work completed.

So where does a project manager fit?

Here is the key point: the project manager does not appear in the LOE at all. It is not a regulated role in Spain, and that has an important consequence.

The three roles above carry a specific, bounded legal duty: they answer for the works matching the design and the regulations. That is a technical responsibility, and they discharge it. But none of them is engaged to defend your budget, negotiate your contract with the builder, or tell you that the cheapest of five tenders is going to end up the most expensive.

The project manager is. They are not another technician on site — they are your representative on it.

Side by side

Site directorExecution directorProject manager
Regulated by the LOE?YesYesNo
Answers forWorks matching the designMaterials and workmanshipThe project meeting your cost, time and scope objectives
Engaged fromOnce the design existsStart on siteBefore you buy the plot
Controls the overall budgetNot their roleCertifies work doneYes, start to finish
Negotiates with the builderNoNoYes
Works forThe designBuild qualityYou

Four things nobody else does

Deciding before you commit

The site director is appointed once a design exists. By then you have bought the plot and decided what to build. If that plot has a planning restriction limiting what you can build, or if the brief you want will not fit the budget you have, that needed to be known earlier. Feasibility work sits with the project manager, and it is where the decisions with the biggest financial consequences get made.

Tendering properly

Comparing five builders' quotes is not a matter of reading the bottom line. It means verifying that all of them have measured the same thing, spotting missing items, identifying which low bids will be recovered through variations later, and drafting a contract that protects you. No LOE role is engaged to do this.

Controlling cost and time forward, not backward

Execution management certifies what has been built, which is looking backwards. Project control looks forwards: at this rate and with these deviations, when will we finish and at what cost? A deviation spotted in month three can be corrected. The same deviation discovered in month nine can only be absorbed.

Being your single point of contact

This matters more if you are not in Spain full-time, or not working in Spanish. Without a project manager you are refereeing between architect, builder, surveyor and installers, using technical information you have no reason to understand, in a language and a regulatory system that are not your own. With one, you deal with a single person who answers to you and to nobody else.

It does not replace anyone

To be clear, because this is sometimes misunderstood: a project manager does not replace the architect or the statutory site roles. Those are legally required and do essential work. The project manager is additional, and fills a gap that sits empty on most projects — someone whose only brief is that this turns out well for you.

Put differently: the architect protects the design, the surveyor protects build quality, the builder protects their margin. All legitimately. The question is who is protecting you.

At Mellado PM we work exclusively for the owner. We have no commercial ties to contractors or suppliers and take no commission from anyone. Our only interest is that your project is delivered on the agreed time, cost and quality.

Before you decide

Which of these do you actually need?

Not every project needs a project manager, and saying so is part of my job. Tell me what you are planning to build and I will give you a straight answer on whether it is worth it, what I would do, and what your architect can handle.

Message on WhatsApp → or send an email

If you do not need me, I will say so.

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