The costliest apartment renovation mistakes are doing finishes before services, accepting a vague lump-sum quote, assuming a wall can go without checking, closing walls before testing pipes and electrics, ignoring the community of owners and choosing finishes that do not suit the use of the flat. Each is avoidable with a clear sequence, an itemised quote and checks before anything is covered.
Mistake 1: Why is doing the finishes before the services so costly?
The most common and most expensive mistake. A new kitchen goes in, the walls are painted, the floor is laid — and then the electrics fail an inspection or the old pipes start leaking. Everything that covers them has to be broken and redone. In an older flat, decide on the services first, even if you plan to renovate in phases. Our services guide explains how to judge their condition.
Mistake 2: Why is a vague quote a problem?
A quote that says “bathroom renovation” with a single figure tells you nothing about what is included. Does it cover new waste pipes? Waterproofing? Who buys the tiles? When something is not included, it becomes an extra. An itemised quote, with every task, unit and quantity on its own line, is the best protection against surprises and the only way to compare contractors fairly.
Mistake 3: Assuming a wall can come down
Owners often plan an open-plan kitchen around a wall that turns out to be structural, or a bathroom move that the waste cannot support. Check before committing: drawings, a technician’s view for anything doubtful, and an on-site check of waste levels. Our layout guide explains what to verify.
Mistake 4: Covering up without testing
Once tiles and plaster go on, nobody can see the pipes or cables. Pressure-testing the water supply, checking waste connections and having the electrical installation verified by the authorised partner installer before closing walls takes little time and avoids the worst kind of problem: the one found after handover, behind new finishes, sometimes in the neighbour’s ceiling.
Mistake 5: Forgetting the building
Starting works without informing the community’s representative, ignoring rules on working hours, blocking the lift with materials or leaving debris on the landing creates conflict fast. The horizontal property law requires owners to inform the community before works, and shared elements need its agreement. A short note to the administrator and good site manners prevent most problems.
Mistake 6: Choosing finishes for photos rather than use
A finish that looks perfect in a showroom may be wrong for a rental flat, a home with pets or a bathroom without good ventilation. Think about cleaning, wear, humidity and repair. For flats near the sea, consider how metal fittings and exposed fixings cope with a salty atmosphere, and ask for materials suited to that environment.
Mistake 7: Splitting the job between uncoordinated trades
Hiring the plumber, the electrician, the tiler and the painter separately can work if you are prepared to coordinate them. Often, nobody does, and each blames the others for delays and defects. With one contractor coordinating everything, there is one sequence and one person responsible. See our full apartment renovation page for how that works in practice.
Mistake 8: Leaving decisions until the last minute
Choosing tiles, taps or kitchen units while the trades are waiting creates delays and rushed choices. Some items need ordering in advance, and late decisions can disrupt the whole sequence. Make the main choices before work starts, keep a simple list of what is decided and what is still open, and know which decisions are needed by which stage. On our jobs we tell you in advance what we need from you and when, so nothing stops the site. If you are abroad, it helps to have samples or photos of the options sent to you early, so the decision is made calmly rather than over a hurried phone call while the tiler waits. The same applies to small items that are easy to forget, such as door handles, light fittings and the position of the television point.
Mistake 9: Not keeping records
Owners who do not keep the quote, invoices, certificates and photos of the hidden services regret it later: when selling, when letting, when a leak appears or when a new electricity contract needs the certificate. Ask your contractor for photos of pipe and cable routes before walls are closed, labelled by room so they are easy to find years later, and keep them with the property documents together with the electrical installation certificate issued by the authorised partner installer where the work required one.
Bauman Raymond Attila · Reforma Pisos Málaga · Avenida Antonio Belón 3, Marbella. Last reviewed: 05/11/2026.
