Design and build under one roof or separate: pros and cons

What should I choose: design and build under one roof, or separate firms?

One company gives speed and a single point of responsibility; separate parties give independent oversight and competitive quotes. Neither model is better by default: the better one is where it is clear who is responsible for what and who checks the checker.

Below is a candid comparison on five criteria: cost, accountability, quality control, speed and flexibility. At the end, a list of what to check whichever you choose.

Is a design-and-build contract cheaper?

Not necessarily. An integrated contract saves on coordination and downtime, but removes the comparison of competing quotes. The result depends on what a mismatch error would cost you and how much time you want to spend tendering.

When designer and contractor are separate, the contractor prices a finished project and you receive two or three comparable figures. That is a strong lever if the project is detailed. When they are the same company, estimate and project are prepared in parallel and the price is built alongside the decisions. That saves weeks, but checking the price against the market is harder.

Do not trust promises of savings without figures. The right question is what the price consists of and what it leaves out. Compare lists of works and materials, not totals, as we covered in the article on comparing quotes.

Who controls quality if the designer and contractor are the same company?

Whoever you appoint separately. When one company designs and builds, checking its own work needs an outside eye: a technical professional who signs the records, an independent expert at handover or at least a clear procedure of photo reports and stage records.

Three mechanisms work in practice. First: an independent technical site director who is not paid by the contractor. Second: payment by stages after signed records, where you see the list of what was done. Third: handover with an expert you invite yourself. They complement each other.

Under the Building Act (LOE), technical direction on major works is divided into director de obra and director de ejecución. If your project requires them, they are already an independent check. Smaller projects have none, and it has to be provided for in the contract.

What if the designer is hired separately?

Bring everyone into one scheme before work begins: one set of drawings, one change procedure and one person who decides on site. Without that, everyone points at the other.

Start with a meeting of designer and contractor before the building contract is signed. The contractor reviews the project and names difficulties. The designer corrects the drawing or defends the decision. Then each contract records: who approves a material substitution, who answers if a detail does not fit, how often the designer visits the site and how design supervision is formalised.

If designer and contractor disagree, you decide, but on a written opinion, not on mood. Agree on that referee in advance: it can be the project's technician. For an owner outside Spain, one shared channel and a weekly photo report remove most misunderstandings.

How do I compare quotes across different models?

Bring them to the same scope: the same set of drawings, the same materials specification, the same exclusions. Only then does the price difference say something about the contractor and not about what is included.

Check four points. Content: whether every chapter is there, from demolition to cleaning. Materials: whether brands and series are named or it says "tile of your choice", which leaves room for a difference. Unmeasured items: provisional sums (partidas alzadas) must be named and justified. Exclusions: what the contractor left out, for example permits, waste removal, sanitaryware, lighting, furniture.

If one company gives an integrated quote including design and another only the building work, add the cost of the project and design supervision to the second. Otherwise the comparison is unfair. The type of quote also matters: a fixed price and a settlement by measurement share risk differently.

What should I check whichever model I choose?

Five things: who signs the project, who is accountable on site, how changes are priced and approved, how payments work and how you verify the result. This applies to any model.

Ask who exactly runs your site and how to reach them. Request a sample contract and handover record before you decide. Find out how material substitutions and extra works are formalised and whether they are always in writing. Check that payment follows stages and the advance does not cover everything. Ask whether the company carries liability insurance and whether you can invite an outside expert.

A good company answers these calmly and specifically. If asked about independent oversight you are told it is not needed, that is an answer too.

How does BCN YARD work within these models?

We run renovation and interior design, one person responsible for the site stays in touch in Spanish and Russian, payments follow stages under the contract and the exact price is given after the visit and measurements. If you already have a designer, send us the project: we will price it from your drawings so you can compare it with other offers.