Rules that raise the cost per square metre of Spanish housing: what to keep and what to cut

Miriam González put a specific complaint near the centre of Democracia 21's housing pitch in her launch speech on 10 October (our overview of the party's proposals sums it up). She argued that a great deal of regulation, much of it absurd, pushes up the cost of each built square metre until protected housing no longer pays to build. That is the party's claim. It deserves the test we would apply to anyone's: which rules, how much, and what to do about each one.

The official diagnosis points the same way. In June 2026 Spain's competition authority, the CNMC, published a study (E/CNMC/001/25) of the whole journey from raw land to finished flat. It places Spain among the OECD countries with the most restrictive land-use rules, finds that land can make up as much as 45% of a home's final price, and describes a process loaded with building controls that pile up, delay licences and hold back the start of work. Its recommendations include adjusting building requirements and burdens, avoiding duplicated or uncoordinated checks, replacing prior licences with responsible declarations where possible, and creating urgent procedures for protected housing. So the regulator agrees with the direction of González's complaint. The useful work is in the detail, rule by rule.

Parking: the clearest case to cut

The rule with the weakest case is the parking minimum, the requirement to build a set number of car spaces with every home. Underground spaces mean digging and extra basements, and the bill lands on every flat whether its owner drives or not. M. Nolan Gray, whose Arbitrary Lines (2022) is the sharpest recent case against American zoning, puts minimum parking requirements on his list of reforms alongside minimum floor areas and lot sizes. He wants planning to concentrate on genuinely incompatible and disruptive activities and to stop prescribing everything else.

Spain is moving on this, at two speeds. The Barcelona Metropolitan Area (AMB) provisionally approved a change to its general plan on 26 May 2026. Inside the ring roads, free-market housing would need one car space for every four homes, and protected rental housing would need none at all. The plan's own report cites figures from Barcelona's municipal housing institute: in 2016 only 44% of the spaces in that kind of housing were used by its residents, and the rest were sold or let to outsiders. The AMB's stated reason is public space, wider pavements and greener streets, and the saving on building costs comes with it. The same change requires at least two bicycle spaces for every new home.

Madrid has gone part of the way. Its Law 2/2026 of 11 June sets the parking allowance for all protected housing at one space per home, a level that until then applied only to publicly promoted housing, and the preamble says why: to make construction costs more efficient and fit new mobility habits. The same law lets office and hotel plots switch to protected housing, and allows up to 20% more floor area and 30% more homes on vacant plots zoned for protected housing, as long as all of it goes to protected homes. Both regions are trimming. Barcelona cuts deeper, and its own data shows the spaces were going unused.

Sizes, terraces and well-meant extras

Minimum-size rules are harder to judge. A floor below which a home is unhealthy protects people, and overcrowding is real. The Basque Government's 2022 habitability decree shows how quickly that floor rises, though. It sets 35 square metres of usable space for a home for two, kitchens of at least 7, living rooms of 13 and bedrooms of 10, and it adds at least 4 square metres of terrace or balcony, or 8 more square metres of living room. Every one of those rules has a good reason behind it: light, air, accessibility, a kitchen open to the living room so that housework is shared. Added together, they define the smallest legal flat, and the smallest legal flat sets the cheapest home a builder can offer. The decree did one thing right on cost: outdoor space up to 10 square metres stops counting against buildable floor area, so the terrace doesn't eat into the number of homes.

The technical code, and the price nobody publishes

The national Building Technical Code, the CTE, is where the rules on structure, fire, accessibility and energy live, and it holds the requirements most worth defending. Fire safety and sound structures are the reason building codes exist. Energy standards cut bills for decades, and EU law asks for them: the Energy Performance of Buildings Directive (2024/1275) sets zero-emission new buildings from 2030.

The argument is about how far past that line Spain goes, and at what cost. The ministry is drafting a CTE reform. Jorge Ginés, director general of the Madrid developers' association ASPRIMA, wrote in December 2025 that Spain's code is already among the most demanding in the world, that it applies the same requirements to luxury flats and protected housing, and that the draft goes further than the directive, down to bicycle-parking rules that could force an extra basement. He cites estimates from Madrid's Colegio de Aparejadores of €12,000 to €15,000 plus VAT per home at first, and over €18,000 once every measure is in force. These figures come from the industry that pays the bill, and should be weighed that way. No official body has published a competing figure.

That gap is where our answer starts. The left is right to defend the standards that keep residents safe, make buildings usable by everyone and cut emissions, and to insist that homes built with public help stay affordable for good. The market-liberal tradition is right that rules adding cost without a matching benefit should go, parking minimums first and oversized floor areas next, and that a protected home whose regulated price sits below its building cost simply never gets built (our piece on social housing in Spain has the numbers on that price).

What fits neither camp is a method: treat building rules like public spending. Every requirement would carry a published price tag in euros per square metre, calculated by whoever writes it, checked by an independent body and set beside the benefit it buys. Rules would live in one national technical code, with regions adapting only what is truly local, and each would be checked once on site, which is the CNMC's point about duplicated controls. Each rule would also get a review date, after which it lapses unless someone shows it still earns its cost, the same logic as our proposal for sunset clauses in Spanish law. Fire escapes would pass that audit easily. Plenty of parking minimums would fail it. The CTE reform is the place to start, with its price per square metre published before anyone approves it.