# Marbella Villa Conservatory & Terrace Enclosure: Permit, Cadastral Re-Count, IBI Impact

The most innocent-looking renovation on the Marbella PGOU is the most expensive one to do wrong. Glazing-in a terrace, adding a winter garden, enclosing a porche — all read as "soft" changes that owners think need no permit. They are categorically obra mayor under LOUA, they trigger a full cadastral re-count that propagates into IBI for the life of the property, and they create discrepancia catastral that the next buyer's lawyer will find in 90 seconds.

## Direct answer

Adding any **fixed glass conservatory, terrace enclosure, or winter garden** to a Marbella villa is **obra mayor under LOUA Article 169** and **counts as constructed habitable area (m² construido) under the cadastral and CTE definitions**. This triggers a cadastral update via Modelo 902N within 60 days of completion, which typically increases the **valor catastral by 5–15%** and the **annual IBI by a corresponding 5–15%**.

Permit cost runs **€1,800–3,500** in council fees plus arquitecto técnico project (€2,500–6,500), the build itself runs **€1,200–2,800/m²** depending on glazing class, and the rebound effect on IBI is permanent. The "I just want to enclose the porche" project on a 35m² area frequently becomes a €60,000 all-in commitment with permanent IBI uplift of €350–900/year.

## Why glass enclosures are not "soft" works

The legal definition of "superficie construida" under the cadastral methodology (RD 1020/1993 + RD-Ley 5/2022) is unambiguous: any roofed area with vertical enclosure (walls, glazing, doors, removable panels with closing function) counts as constructed area. A pergola without enclosure does not. A pergola with retractable sides does not until the sides are installed permanently. The moment glazing goes in, the area transitions from "porche" (porch, not constructed) or "terraza cubierta" (covered terrace, partial coefficient) to "superficie construida" (full coefficient).

For cadastral valuation purposes, the coefficient table looks like this:

| Area type | Cadastral coefficient | Counts toward IBI? |
|---|---|---|
| Interior habitable (vivienda) | 1.00 | Yes (full) |
| Glazed conservatory / closed winter garden | 0.85–1.00 | Yes (high) |
| Covered terrace with one open side | 0.50 | Yes (partial) |
| Covered terrace with two open sides | 0.30 | Yes (lower) |
| Open terrace (no roof) | 0.10 | Minimal |
| Pergola without enclosure | 0.05–0.10 | Minimal |
| Built basement (storage, not habitable) | 0.50 | Yes (partial) |
| Garage built | 0.60 | Yes (partial) |

A 40m² open terrace transitioning to a 40m² fully-enclosed conservatory shifts the cadastral count from 4m² equivalent (40 × 0.10) to 34–40m² equivalent (40 × 0.85–1.00). That is a 30–36m² increase in the valor catastral input, which is roughly 8–15% of a typical 250–400m² Marbella villa's existing cadastral base.

## Worked example — 35m² terrace enclosure to glass conservatory

A 320m² Sierra Blanca villa, current valor catastral €620,000, current IBI €4,650/year (Marbella 0.75% IBI rate). Owner adds a 35m² glass conservatory on the south terrace, retractable glass walls (Lumon-style sliding system), structural ceiling above existing porche roof.

| Cost item | Amount | Notes |
|---|---|---|
| Glass system supply + install (Lumon, Solarlux, or equivalent) | €52,500 | 35m² × €1,500 mid-spec |
| Aluminium framing + structural integration | €8,500 | Marine-grade for coastal exposure |
| Floor levelling + tiling continuity | €4,200 | Matching interior |
| Heating extension (radiator or split A/C) | €3,200 | Year-round usability |
| Electrical extension + lighting | €1,800 | New circuit + boletín |
| **Build cost** | **€70,200** | |
| Arquitecto técnico project + dirección | €3,510 | 5% of build |
| Estructurista (calc for added roof load) | €1,200 | Mandatory under CTE |
| Coordinador de seguridad y salud | €700 | RD 1627/1997 |
| Licencia obra mayor (Marbella council) | €2,200 | Marbella scale 2026 |
| ICIO (4% of project value) | €2,808 | Marbella ICIO rate |
| Tasa basura obras | €380 | 1 skip |
| Modelo 902N cadastral filing (within 60 days completion) | €380 | Statutory |
| Boletín eléctrico for new circuit | €280 | Required for nueva cédula |
| **Total soft + permit** | **€11,478** | **16.4% on top of build** |
| **All-in conservatory project** | **€81,678** | |
| **Cadastral impact** | | |
| Existing valor catastral | €620,000 | Pre-renovation |
| Approximate cadastral uplift (35m² × 0.85 coefficient × per-m² cadastral rate) | +€72,000 | Junta-set rate ~€2,420/m² in Sierra Blanca cadastral zone |
| New valor catastral (approx, post-update) | €692,000 | +11.6% |
| New annual IBI (Marbella 0.75% × €692,000) | €5,190 | +€540/yr permanent |

The €540/year IBI uplift is permanent for as long as the conservatory exists. Over 20 years that is €10,800 in additional IBI, plus the corresponding impact on valor de referencia at next sale (which propagates into the next buyer's ITP and your plusvalía). See our [cadastral reassessment 2027 guide](/article-cadastral-reassessment-2027-en) for the broader impact.

## Where buyers commonly trip up

**Filing as obra menor.** Owners reading the conservatory as "non-structural" file as obra menor. The council technical office rejects on the first review — any roofed enclosure transitioning area into superficie construida is categorically obra mayor. Filing wrong adds 4–8 weeks to timeline and triggers automatic scrutiny on any other works at the property.

**Skipping the Modelo 902N filing.** The 60-day cadastral update deadline post-completion is statutory under RD 417/2006. Missing it means the cadastral discrepancy is unresolved, the next nota simple at sale will flag it, and the next buyer's lawyer will use it to negotiate price down 3–8% or stall the deal. The €380 filing is not optional.

**Buying a villa with an unpermitted prior conservatory.** Walk the cadastral plan against the physical villa. Conservatories added in the 2000s–2010s without permit are extremely common in Marbella secondary stock. The discrepancia surfaces at your sale, not the previous owner's purchase. Demand cadastral cleanup or price reduction at arras. See our [cadastral verification guide](/article-marbella-cadastral-verification-en).

**Assuming "removable" glass exempts you.** Lumon and similar retractable systems are marketed as "movable" to imply permit-free status. They are not. Any system installed as a fixed building element with frames, tracks, and structural integration counts as enclosure regardless of whether the panels themselves slide. Marbella council technical office treats this consistently.

**Ignoring the thermal-bridge and energy-rating consequences.** New enclosed area falls under CTE-DB-HE energy code requirements. The conservatory must meet minimum thermal-transmittance and solar-control thresholds. Cheap single-glazed installations fail the energy certification and require recertification of the villa's overall energy rating — which often downgrades the villa's Class B/C/D rating by one full step.

**Forgetting community consent.** If the villa is part of a horizontal-property regime (gated urbanisation, branded residence), façade modifications require community approval under Ley 49/1960 de Propiedad Horizontal Art. 17. Adding visible glazing to a façade often requires majority comunidad consent. Owners who skip this trigger comunidad legal action and forced removal.

## The "winter garden" tax-planning angle

Some owners structure conservatories as detached garden rooms (separate, not contiguous with the main villa) to argue they are not main-vivienda area for habitable-floor calculations under PGOU. This rarely works — Marbella's PGOU treats any closed structure on the plot as built m² regardless of contiguity, and the cadastral methodology mirrors this. The detached-garden-room argument is occasionally successful in inland Andalucía municipalities with looser PGOU regimes; it is not viable in Marbella.

## When to call Muse

Before you commission a glass conservatory, winter garden, or terrace enclosure on a Marbella villa — particularly any project above 20m² added area — book a permit-and-cadastral audit so we can model the IBI uplift, confirm the licence path, and check community consent requirements. The 15-year cost of getting this wrong compounds into five figures.

## FAQ

**Can I add a pergola with motorised louvres without permit?**
Open pergolas (no glazing, no permanent walls) are typically obra menor or comunicación previa, depending on size and structural integration. Motorised louvres that fully close to weatherproof status are a grey area — most Marbella architects treat them as enclosure for safety and file obra mayor. The grey area is not worth the legal exposure on a high-value villa.

**Will adding a conservatory affect my property insurance?**
Yes. New built area triggers re-rating under Ley 50/1980 Art. 11. Notify your insurer within 15 days of completion. Premium uplift typically 8–18% of building portion. Failure to notify invalidates conservatory-area claims.

**Does the IBI uplift apply immediately or with a lag?**
Catastro processes Modelo 902N within 12–24 months typically. New IBI applies from the year following processing, but can be back-charged to the completion date if cadastral office discovers via aerial photography that the work was completed earlier. Best practice: file 902N promptly and budget the IBI uplift from year 1 of completion.

**Can a glass conservatory increase the sale value enough to justify the IBI hit?**
For well-designed conservatories in premium urbanisations, yes — the usable-year-round area uplift typically adds 1.2–1.8× the build cost in achieved sale price. For poorly designed retrofits or thermally bad installations, often no — the discrepancia catastral and odd aesthetic can knock more off the price than the area adds.

**What about enclosing a basement or built garage area for storage or gym use?**
Basement or garage transitioning from non-habitable storage/parking to habitable use (gym, cinema, guest annex) triggers cambio de uso — a more complex licence than simple enclosure. Cadastral coefficient jumps from 0.5–0.6 to 1.0 for the affected area. Often a 20–35% increase in valor catastral on a basement-heavy villa.

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**Planning a conservatory or terrace enclosure?** Muse Marbella runs permit-and-IBI audits before you sign the build contract. Founder Max Bykov reviews every brief personally. Compare with the broader [renovation permit framework](/article-marbella-villa-renovation-permits-en), the [cadastral reassessment 2027 guide](/article-cadastral-reassessment-2027-en), and our [complete buyer guide](/marbella-property-buying-complete-guide-2026).



## Related Reading

- [Marbella Villa Renovation Permits — Licencia de Obra Menor vs Mayor | Muse Marbella](/article-marbella-villa-renovation-permits-en)
- [Cadastral Reassessment 2027 — What Marbella Owners Need to Know | Muse Marbella](/article-cadastral-reassessment-2027-en)
- [Marbella Cadastral Verification — How to Check the Plan | Muse Marbella](/article-marbella-cadastral-verification-en)
- [Marbella Property Tax Deadlines 2026 | Muse Marbella](/article-marbella-property-tax-deadlines-2026-en)
- [Marbella Architects for Villa Renovation & New Build | Muse Marbella](/article-marbella-property-architects-en)