In short: what a proper estimate contains
A renovation estimate should show each piece of work as a line item: what is done, in which unit, in what quantity, at what unit price, with which material and what that price includes. The net amount, VAT rate, VAT amount and total should be shown separately. Plus three things that are often forgotten: exclusions, provisional quantities and open decisions, and the rule by which changes will be priced.
A single turnkey flat renovation figure lets you neither compare offers nor, later on, work out what was promised.
Anatomy of a line item
Compare two lines. The first: Bathroom, 9,000 EUR. The second: Waterproofing of shower-zone floor and walls with liquid membrane, reinforced corners and junctions, flood test; m², 8.4; price per m². The second says what will be done, with what and how much, and it can be checked on site with a tape measure.
A good line item also shows what it includes: substrate preparation, waste removal, protection of adjacent surfaces. If those have their own lines, even better. If they appear nowhere, ask where they have been priced.
Sections: so you can see what is missing
An estimate is easiest to read when it is split into sections following the order of works: preliminaries and protection of the building, permit, demolition, partitions, electrics, plumbing, air conditioning and ventilation, plastering and screeds, flooring, tiling, joinery and doors, painting and final clean.
That structure exposes the gaps. If an estimate for a full renovation in the Eixample has no air-conditioning section or no waste removal, it is either an exclusion that should be written down or a future extra. On a job like the 250 m² children's psychology centre, with heat-recovery climate control and 24 concealed doors, those systems need their own sections; otherwise they cannot be checked or paid for in stages.
Materials: a specific model or an allowance
For every significant material the estimate should state either a specific model or an allowance for you to choose within: parquet at a price per m², for example, within which you pick. In the second case what matters is what happens if you choose something dearer or cheaper: the difference is recalculated at the same unit rate, and that should be written down.
Also clarify who buys the material. If you buy something and the contractor installs it, record who is responsible for the delivery date and for checking the material on arrival.
VAT: four figures, not one
Net amount, VAT rate, VAT amount and total should each appear separately. Tax treatment is checked for each specific transaction, and the reduced rate does not apply automatically just because it is a home: the conditions determine which rate is correct. There is a separate article on IVA for renovations; if in doubt, ask your gestor.
Our price benchmarks are excluding VAT: Basic from 1,000 EUR/m², Standard from 2,000 and Luxury from 3,000. In the estimate, IVA is added as a separate line.
Exclusions, provisional quantities and open decisions
Ask for an explicit list of what the estimate does not cover: furniture, appliances, light fittings, design and site supervision, permit fees, work on the building's shared elements. Anything written neither as included nor as excluded becomes the subject of an argument later.
Items whose quantity cannot be known until things are opened up, such as replacing a decayed section of beam or a pipe inside a wall, should carry a unit rate and be marked provisional. Open decisions, such as the tiles or the kitchen model, are flagged with the date by which a choice is needed.
Changes, payments and validity
Before starting, agree how changes will be priced: at the unit rates in this same estimate, and for new work with a written costing that you approve before it is done. A let's do it and work it out later halfway through a job almost always ends in a dispute.
It helps when payment stages are tied to sections of the estimate: demolition complete, first-fix services complete, and so on. We work with payment under the contract in stages, and prepare the estimate after visiting and measuring the property. Also check how long the estimate is valid: material prices change, and after a few months it may be recalculated.