The short answer
The danger of a verbal quote is that it contains nothing but a number. Scope, materials, timing and payment terms are remembered differently by each side, and in a dispute neither version can be proved. Any job worth more than a few hundred euros or lasting more than a couple of days needs a written document.
Something small like replacing a tap can be agreed in conversation. A kitchen, bathroom or whole-flat renovation cannot. The bigger the amount and the longer the job, the more places memory lets you down, even when both sides are acting in good faith.
Where expectations clash
Scope. For one person, a "turnkey bathroom" includes strip-out, debris removal, new pipework, tiling, sanitaryware and a mirror. For another, it means tiling and fitting whatever the client buys.
Materials. "Good tiles" and "a decent tap" are not a specification. Two products in the same category can differ in price several times over.
Who buys. If the client supplies materials, who is responsible for delivery dates, receiving goods, breakages and returns?
IVA. Was the figure with tax or without? On a renovation worth tens of thousands of euros, that is serious money.
Timing and payment. How much is paid upfront, for what and when, and what happens if the work runs late.
Cleaning and debris. Who removes the rubble, who pays for the skip and its permit, and what state the flat is handed back in. In a verbal deal these details never come up until the moment someone has to pay for them.
What it looks like in practice
A hypothetical example. The owner of a flat in Eixample agrees with a builder to redo the kitchen "for 30,000". A month later the kitchen is stripped out, and the builder says that rewiring back to the consumer unit and a new screed were not included: he only counted units, worktop and finishes. The owner is sure they agreed on "everything, turnkey".
Nobody will ever know who is right. Work stops, the builder will not return until he is paid more, and finding another contractor for a half-demolished kitchen is hard: nobody wants to take responsibility for someone else's half-finished job. In the end the owner pays more than a proper quote would have cost and loses months.
What a WhatsApp chat is worth
A chat is better than nothing. A message like "confirmed, kitchen including electrics and screed for 30,000 with IVA" does pin down something specific. But a chat rarely contains the full list of works, and voice notes or photos captioned "like this" prove very little.
If the contractor only works through messaging, ask them to send the quote as a file: with company details, NIF, the list of items, materials and the total with and without IVA. Refusing to do that on a project worth tens of thousands of euros is a warning sign, which we cover in the article on warning signs when choosing a contractor.
How to get the agreement onto paper
The minimum before work starts: an itemised quote with materials and quantities, the total with and without IVA, a payment schedule tied to stages, timing, company details and both parties' signatures. The full contract is covered in another article; here that minimum is enough.
If the contractor does good work but is not one for paperwork, do it yourself: write an email setting out how you understood the agreement and ask them to confirm or correct it. It takes an hour and heads off most future disputes.
Changes during the work are recorded the same way: what changes, what it costs, how it affects the timeline and who approved it.
Why the contractor needs it too
A written quote also protects whoever does the work. Without one, every "I thought that was included" turns into free work or an argument. A serious company is the first to insist on the document, because stages are signed off and payments calculated against it.
At BCN YARD the quote is prepared after the site visit and measurements, item by item, and goes into the contract. Payments follow the contract, in stages. Each project has one person in charge, in Russian or Spanish, and changes are approved in writing before they are carried out. We reply to enquiries within an hour.