The fifth elevation, re-engineered.
One architectural plane, two outputs. The roof we already install for the sun is the roof that catches the rain.
The roof was already the answer.
A luxury villa on Ibiza installs, on average, three to five hundred square metres of photovoltaic surface. That surface is tilted, glazed, food-grade in everything but designation, and exposed to the only meaningful source of fresh water the island receives — direct rainfall.
Las Lluvias begins with a single architectural question: if we are already committing this much sealed, inert, sun-facing area to the production of electricity, what does it cost to make the same plane do a second job. The answer, properly engineered, is small. The output, properly certified, is potable rainwater. The fifth elevation — the roof — stops being a single-purpose surface and becomes dual infrastructure. The villa keeps its silhouette. The architect keeps his line. The hydrology of the parcel changes entirely.
Architecture A — Solar-as-catchment.
In the primary typology, the photovoltaic surface itself is the catchment. The same tilted, tempered, self-cleaning glass that generates electricity is the plane on which rainfall is collected. There is no second roof. The PV array is the roof, and the roof is the catchment.
This is the most integrated, most discreet, and — under the post-2024 IDAE NextGen subsidy regime — the most economically efficient of the two configurations. Marginal cost is contained, because the expensive surface (the PV glass) is already being purchased for energy. The water layer adds gutter geometry, a continuous downstream skin to capture inter-panel runoff, the treatment train, and the cistern. Nothing is added to the silhouette that an architect must defend.
It is the typology we specify as the default for new-build and for full-roof retrofit on parcels where heritage and planning constraints permit the PV plane to be read as the finished elevation.
The same surface that converts photons to electricity converts rainfall to a certifiable potable feedstock. No visible additional infrastructure. The architectural register is unchanged; the building's relationship to its parcel is transformed.
Architecture B — Galvalume catchment skin.
The alternate typology decouples the two outputs. Beneath a rail-mounted photovoltaic array sits a continuous, food-grade Galvalume standing-seam roof. The Galvalume layer is the catchment. The PV above is independent — geometrically, thermally, and from a permitting perspective.
Architecture B exists because Ibiza is not a uniform regulatory landscape. Heritage zones, BIC-adjacent parcels, and certain Consell-protected typologies do not always permit the PV plane to read as the visible roof. In those settings, a traditional or near-traditional finished elevation is required, and the catchment must be solved beneath it. Galvalume, specified to potable-contact grade, gives us a continuous, hygienic, reflective skin that satisfies EU DWD certification without forcing the PV to perform the architectural duty as well.
It is also the conservative path for the first owner who wants the rainwater outcome without committing, on the same parcel and at the same time, to a fully integrated PV roof. Architecture B can be installed today, and the array above it upgraded later.
Continuous Galvalume catchment beneath a rail-mounted PV array. Decoupled, conservative, certifiable. The configuration we specify where heritage protection, planning constraints, or phasing requirements rule out the integrated typology.
Five elements. One envelope.
Whichever typology a parcel demands, the roof assembly is read as five vertically stacked layers, each doing a separate piece of work. The composition lets the same envelope perform, simultaneously, as a cool-roof, a shaded-roof, and a Passivhaus-grade thermal envelope. Three roof types in the architectural literature, executed as one assembly.
- i. PV array Tilted, glass-fronted, raised on aluminium rails. Generates electricity; serves as the primary catchment face and as the building's solar shade.
- ii. Catchment skin Continuous food-grade surface — Galvalume standing-seam or potable-grade membrane. Captures runoff; reflects residual radiation back to sky.
- iii. Ventilated air cavity Convective thermal buffer. Removes summer heat before it reaches the insulation; manages shoulder-season moisture migration.
- iv. Insulation Rigid layer specified to Passivhaus thresholds. Vapour-managed. The thermal workhorse.
- v. Structural deck Concrete forjado or engineered timber. Carries load; defines the interior soffit datum.
Each layer is conventional in isolation. The novelty is the stack — and the discipline of refusing to let any single layer do two jobs badly when two layers can do them well.
vs. traditional teja construction.
The vernacular Ibicenco roof — terracotta tile over an uninsulated or lightly insulated deck — is a thermal liability before it is anything else. The Las Lluvias assembly is not a stylistic alternative to it. It is a different category of building envelope.
| Metric | Traditional teja | Las Lluvias assembly |
|---|---|---|
| Peak summer roof-surface temperature | 60–70 °C | 30–45 °C |
| Assembly U-value | 0.6–1.2 W/m²K | ≤ 0.15 W/m²K |
| Winter heat-loss share via roof | 20–30 % | 5–10 % |
| Certification eligibility | BREEAM Pass | BREEAM Outstanding · Passivhaus Premium |
The constraint is the product.
The discipline of Las Lluvias is not to add. It is to take a surface the owner is already committing capital to install, refuse to let it serve a single output, and re-engineer it into infrastructure. The architectural register that follows from this discipline is the register of restraint — the unornamented horizontal, the suppressed datum, the silhouette the eye does not catch on. The aesthetic vocabulary is the vocabulary of the contemporary luxury hospitality estate at its most reduced: stone, lime, water, shadow.
Nothing is added to be seen. Everything that is added does work. That is the architectural argument. The hydrology of the parcel is the dividend.