Price reference: 2026. Last reviewed: 16 September 2026.
Converting a Madrid flat into a well-planned residential room-by-room rental can produce more income than letting the property as a single unit. It also brings higher fit-out costs, heavier use of the installations and more day-to-day management. The investment therefore needs to be assessed as an operating property, not simply as an interior design project.
This worked example estimates the cost of renovating a 90 m² flat in Madrid to a durable mid-range standard. It is intended as an initial investment-screening tool. It is not a contractor’s quotation or a substitute for a measured survey, technical design, legal review, tax advice or financial advice.
Assumptions Used in This Example
- Location: Madrid city.
- Floor area: 90 m² built area, with an assumed usable internal area of approximately 74–78 m².
- Existing condition: an outdated resale flat with services that should be renewed, but no known structural failure, asbestos or major building defect.
- Proposed layout: four valid bedrooms, two bathrooms and a shared open-plan or semi-open-plan kitchen, living and dining area.
- Scope: moderate internal reconfiguration, new electrical and plumbing installations, kitchen, two bathrooms, finishes, furniture and operational equipment.
- Specification: durable mid-range products selected for frequent use, straightforward replacement and controlled maintenance costs.
- Tax assumption: 21% Spanish value-added tax, or IVA, is applied to taxable works and supplies. Some municipal taxes and public charges are not subject to IVA.
- Not included: purchase price, property transfer tax or acquisition IVA, notary and land registry costs, finance, interest, letting fees, income tax or structural works.
The proposed four-bedroom layout is only viable if the flat’s usable area, façade openings, daylight, ventilation, circulation and building constraints allow it. A room should not be treated as a lettable bedroom merely because a partition and door can be installed. The layout and applicable requirements must be checked by a competent professional before the purchase or works are committed.
Estimated Renovation Budget
The figures below are indicative Madrid prices for 2026. The final cost can change significantly according to the district, floor level, lift and access, architectural protection, existing services, specification, contractor availability and measured quantities.
| Budget item | Included work | Estimated cost before IVA | Estimated IVA | Total cost |
|---|---|---|---|---|
| Technical design, permits, municipal charges and management | Measured survey, layout proposal, technical documents where required, administrative management and a provisional allowance for municipal charges and ICIO. | €5,500 | €672; partly outside IVA | €6,172 |
| Strip-out, demolition and waste | Removal of existing elements, internal demolition, loading, transport and authorised waste management. | €5,000 | €1,050 | €6,050 |
| Building work and reconfiguration | New partitions, floor preparation, making good and builders’ work for the new services. | €10,000 | €2,100 | €12,100 |
| Electrical installation and lighting | Consumer unit, circuits, switches, sockets, sufficient bedroom outlets, shared-area supply and LED lighting. | €8,500 | €1,785 | €10,285 |
| Plumbing and drainage | Replacement of internal pipework and adaptation for the kitchen and two bathrooms. | €6,500 | €1,365 | €7,865 |
| Kitchen and appliances | Durable cabinets, worktop, sink, hob, oven, extraction, fridge-freezer, washing machine and dishwasher. | €11,500 | €2,415 | €13,915 |
| Two bathrooms | Waterproofing, wall and floor finishes, sanitaryware, taps, showers and screens. | €13,500 | €2,835 | €16,335 |
| Heating or air conditioning | Reasonable upgrading of the existing system and improved zoning or control where feasible. | €5,500 | €1,155 | €6,655 |
| Internal and external joinery | Doors, basic wardrobes, ironmongery and selective repair or replacement of windows. | €8,500 | €1,785 | €10,285 |
| Acoustic improvements | Targeted treatment to bedroom partitions, soil and waste pipes, and doors; not full soundproofing. | €5,000 | €1,050 | €6,050 |
| Decoration and finishes | Surface preparation, washable paint, flooring, skirting boards and final making good. | €5,000 | €1,050 | €6,050 |
| Bedroom and shared-area furniture | Four beds and mattresses, desks, chairs, wardrobes, living-room seating and dining furniture. | €10,000 | €2,100 | €12,100 |
| Locks, connectivity and operating equipment | Locks compatible with safety and escape requirements, Wi-Fi provision, kitchenware and initial operating equipment. | €3,000 | €630 | €3,630 |
| Final clean | Builders’ clean and preparation for photography and letting. | €900 | €189 | €1,089 |
| Subtotal before contingency | €98,400 | €20,181 | €118,581 | |
| Contingency | Approximately 10% of construction, supply and furniture items; only spent if required. | €9,300 | €1,953 | €11,253 |
| Estimated total budget | €107,700 | €22,134 | €129,834 |
The central estimate is approximately €1,443 per m² of built area, including IVA, furniture, operating equipment and contingency. For acquisition screening, it would be sensible to test a broader total range of €118,000–€148,000. The lower end assumes favourable existing conditions and limited window or heating work. The upper end may apply where services are in poor condition, windows require full replacement, the building is protected or more extensive acoustic work is necessary.
Understanding IVA, ICIO and Municipal Charges
Spanish renovation quotations normally identify IVA separately. The Spanish Tax Agency states that the reduced 10% rate for ordinary residential repair or renovation does not apply where the property is intended for letting. This simulation therefore uses the standard 21% rate as a prudent assumption. The tax treatment of the actual contract and individual supplies should be confirmed before signing.
ICIO is Madrid’s municipal tax on construction, installations and works. It is calculated on the material execution cost rather than on IVA, professional fees or public charges. Madrid City Council currently publishes a 3.75% rate for works begun from 1 January 2024. The definitive taxable base, urban-planning procedure and any other charges must be calculated for the actual project.
Where the Budget Should Be Prioritised
A room-by-room rental should be designed around reliable operation before decorative impact. The main priorities are:
- A compliant and workable layout: valid bedrooms, proportionate shared space, storage and straightforward circulation.
- Electrical and plumbing capacity: several occupiers create higher simultaneous demand for power, hot water and drainage.
- Two bathrooms: for four occupiers, this reduces friction and improves the flat’s market position.
- Acoustic separation: partitions, doors and service pipes require particular attention.
- Durable finishes: washable paint, repairable flooring, robust worktops and replaceable ironmongery.
- Connectivity: stable Wi-Fi coverage and sufficient electrical and data points for each bedroom.
Premium decoration usually adds less operational value than good daylight, a usable desk, adequate storage and a kitchen designed for simultaneous use. Maceta y Cortafrío’s property renovation service for investors in Madrid focuses on aligning the scope of work with the intended letting or disposal strategy. Where the existing condition justifies a complete intervention, see our full renovations in Madrid service.
Indicative Programme
| Phase | Indicative duration | Main work |
|---|---|---|
| Survey and feasibility review | 1–2 weeks | Site inspection, measurements, document review, layout strategy and scope. |
| Design, quotations and municipal procedure | 3–8 weeks | Required documents, comparable quotations, contractor selection and the applicable submission. |
| Long-lead procurement | 3–8 weeks, overlapping | Kitchen, windows, doors, sanitaryware and equipment. |
| Strip-out and base build | 2–3 weeks | Removal, waste management, setting out and building work. |
| Services and closures | 3–5 weeks | Electrical, plumbing, heating or cooling, partitions and acoustic treatment. |
| Finishes | 4–6 weeks | Bathrooms, kitchen, flooring, joinery and decoration. |
| Furniture, testing and handover | 1–2 weeks | Installation, testing, snagging, final clean and documentation. |
A prudent allowance from the first survey to a tenant-ready property is 16–24 weeks. Possible delays include requests for further municipal information, approvals affecting communal elements, defective risers or drainage, protected-building constraints, unavailable products, client changes and faults identified during commissioning.
Basic Financial Model
Idealista reported an average advertised room rent of €587 per month in Madrid during the first quarter of 2026. For a renovated, well-connected and appropriately equipped flat, this model tests a range of €550–€700 per room and uses €625 per room as its central assumption. This is not a rental valuation. Comparable rooms in the same neighbourhood should be reviewed because Madrid is not a single uniform market.
| Estimated renovation investment | €129,834 |
|---|---|
| Central monthly rent per room | €625 |
| Potential gross income | €2,500 per month; €30,000 per year |
| Assumed occupancy | 92% |
| Effective income after vacancy | €27,600 per year |
| Estimated operating expenses | €6,072 per year; 22% of effective income |
| Operating result before finance and tax | €21,528 per year |
| Gross income divided by renovation cost | 23.1% |
| Operating result divided by renovation cost | 16.6% |
| Simple renovation-cost payback | Approximately 6.0 years |
The operating-cost allowance combines utilities where included in the rent, internet, community charges, local property tax, insurance, maintenance, replacements, shared-area cleaning and management. These assumptions must be replaced with property-specific figures.
The percentages above are not the total return on the property investment. They use only the renovation budget as the denominator even though the rental income also depends on ownership of the underlying asset. Without the purchase price, acquisition taxes, notary and registry costs, finance and other transaction costs, a total acquisition yield cannot be calculated.
They are also not an incremental return attributable solely to the works. Measuring that would require evidence of the rent and operating costs achievable before refurbishment and a comparison with the post-renovation position.
Key Risks for an International Investor
- Construction overruns: concealed services, damp, drainage, risers or structural defects can consume the contingency.
- Municipal procedure: the route depends on the scope, the building and any architectural protection. Works may require a declaración responsable, or responsible declaration, or a formal urban-planning licence.
- Residential suitability: a physical subdivision does not automatically make every room acceptable for occupation. Usable area, light, ventilation, escape and building services require review.
- Over-occupation: maximising bedroom count can undermine the shared space, tenant experience and durability of the property.
- Contractual framework: residential room letting should not be confused with tourist accommodation or automatically described as coliving. A Spanish adviser should confirm the contracts, deposits, tax treatment and current obligations.
- Community rules: the title documents and the comunidad de propietarios, or owners’ association, should be reviewed where the works affect communal elements or installations.
- Maintenance and vacancy: more occupiers and contracts normally mean more turnover, repairs, administration and void periods.
Conclusion: Validate the Property Before Committing Capital
As an initial planning figure, an investor should allow approximately €130,000 including IVA to turn a 90 m² Madrid flat into a durable four-bedroom, two-bathroom residential room-by-room rental. The investment case should not depend on bedroom count alone. Layout quality, installations, acoustic comfort, durable finishes and management all influence the stability of the income.
The next step is a measured site visit, document review, layout feasibility check and like-for-like contractor quotations. Maceta y Cortafrío can assess the property, define the renovation scope and organise the work around the intended investment strategy. Request an initial project assessment before treating the renovation allowance as a committed investment figure.
