Design Standards
Building Guidelines
The design standards that keep every Sienna villa in harmony with the community and its natural setting.
These guidelines complement the Sienna Terrenas Master Regulation. They ensure every construction — whether a standard villa or a custom build — reflects the project's contemporary, eco-conscious vision and preserves the value of every property. Detailed plans are reviewed and approved by the project's Advisory Committee. This page summarises version 3.0 of the Design and Construction Guidelines (September 2026); the Spanish original is the only binding version.
Architecture
- Contemporary architectural style, in the same rhythm as the Sienna villas: horizontal volumes, flat roofs, an alternation of solid and open surfaces on the facade, and the villa raised on columns on sloped ground.
- A maximum of 2 levels is permitted. Exposed columns below the lowest enclosed slab do not count as a level.
- Nothing may be built on the main roof, pergolas included — rooftop solar panels are the one exception (see General Directives). Pergolas, louvres and sun shades are allowed on terraces and at ground level, subject to Advisory Committee approval.
- All roofs are flat concrete slabs, with only the slope needed to drain rainwater and never more than 5%.
- Green roofs are recommended.
- The villa's siting must take the neighbouring lots' views into account and avoid facing their main openings directly. The Advisory Committee may require the siting to be adjusted within the lot's buildable envelope.
- Each facade must have openings or, failing that, a change of material. Blind facades in a single material are not accepted.
- On sloped lots, only constructions raised on columns are permitted. Columns must be dark in colour, set back at least 1 m from the plane of the facade and landscaped between — and never enclosed: closing that space, wholly or partly, creates an additional level and is prohibited.
- Designs must adapt to the topography, keep earthworks to the minimum necessary, and favour cross ventilation, passive shading and natural light.
- Villas must harmonize with the natural surroundings, preserving the relevant native vegetation and the lot's topography.
General Directives
- Rooftop solar panels must not exceed 40 cm in height above the slab.
- Air conditioning equipment, water tanks, ventilation units and other technical equipment may not be installed on the roof.
- Air conditioning units, tanks, LPG containers, meters and other technical equipment must not be visible from the facades, the roads, the common areas or the neighbouring lots. They are placed under the villa or in closed enclosures consistent with the project's palette.
- Each villa must have its own wastewater treatment system and a water filtration system.
- A rainwater collection cistern is mandatory, as in every licensed villa type.
- Battery and inverter systems are permitted, installed in a ventilated technical room.
Materials
- The colour palette is that of the natural surroundings: the greens and dark greens of the vegetation, the earth and red-brown tones of the soil, beige and greys.
- White in all its variants — pure white, off-white, bone, ivory — is prohibited on walls, facades, shutters, fences and every other exterior surface.
- Fluorescent or saturated colours, and black over large surfaces, are prohibited. Occasional colour accents are allowed with Advisory Committee approval.
- Doors, windows and shutters are wood, thermo-lacquered aluminium in discreet tones, or wrought iron. Mirrored, reflective and tinted glass is prohibited.
- Favoured materials: certified local or regional woods, natural stone, well-finished exposed concrete, traditional lime wash in the permitted colours, terracotta, and recycled or low-impact materials. Imitation plastic cladding and vinyl may be rejected. Construction materials must be sustainable and suited to the coastal climate.
- Pitched roofs of any kind, metal roofing (aluminium, zinc or other), tiles, and natural or synthetic thatch are prohibited.
Lot Design & Dimensions
- Siting follows the contour lines of the land and keeps earthworks to the minimum necessary.
- No facade of the built volume may exceed 20 m in length. Uncovered terraces and parking slabs are not counted.
- The upstream facade must not exceed 4 m, measured from natural ground level to its highest point. Roof volumes set back from that facade may rise above it, within the lot's licensed maximum roof level.
- The downstream facade must not exceed 11 m, measured from the underside of the lowest enclosed slab to the highest point of the main roof.
- Minimum setbacks: 3 m front, 1.5 m sides, 3 m rear. The 1 m strip along the boundaries reserved to the developer falls inside those setbacks and may not be built on.
- Minimum distance between two buildings: 5 m.
Noise
- Combustion generators, whether fixed or portable, are prohibited.
- Fixed sound systems in outdoor spaces are prohibited.
Parking
- Minimum parking within the lot: 1 space for 1- and 2-bedroom villas, 2 spaces for villas of 3 bedrooms or more.
- Carports must respect the 3 m front setback.
Gardens & Boundaries
- Landscaping uses native or adapted species from the Advisory Committee's reference list. Ornamental lawn is limited and native ground cover comes first.
- Walls and uncovered stairs must not exceed 2 m in height above natural ground level.
- Bungalows, guest houses and other habitable annexes are only permitted where the lot's licensed villa type includes them. They count towards the lot's built area and footprint, and follow the same rules as the villa.
- Solid walls are prohibited as boundaries between lots — only vegetated chain-link fences are allowed.
- The same applies along the roads: non-solid fences and gates are permitted, but not walls.
Construction Site
- The construction site must be kept closed and secure.
- The site must not encroach on the roads or the common areas.
- Any damage caused must be repaired and restored to its original state.
Approval Process
- The preliminary design must be submitted to the Advisory Committee for review and written approval. Silence from the Committee does not count as approval.
- You and your architect may request a preliminary meeting with the Advisory Committee before developing the design, at no charge.
Planning a custom build?
Our lead architect helps you design within these guidelines, and our team handles the Advisory Committee approval process.