Functions and Effects of Skylight Roofs
Most light wells are small and relatively dark, resembling a deep shaft—hence the name. They are also called underground courtyards or sunken gardens, common in mid- to high-end villas connected to basements for layered outdoor living. Covering a light well adds a steel-and-glass skylight roof above the opening, creating a weather-protected enclosed space. Skylights or windows—and preferably motorized operables—allow one-touch ventilation. A glass roof makes the space usable in all weather and brings daylight below grade. Mediterranean styling with ochre walls harmonizes with villa exteriors. Raised trellis and glass roofing boost usable area and solve underground daylighting. Design is tailored to on-site structure, balancing safety and aesthetics.
**
Performance Requirements for Glass Skylight Roofs
Strength, seismic performance, lightning protection, fire resistance, and—for sealed skylights—air tightness, water tightness, thermal insulation, and sound insulation. For example:
Strength: Resistance to wind (and snow) loads per regional wind speed, wind pressure, and snow load values. Consider dead load, wind load, and snow load; omit snow where not applicable.
Seismic performance: Failure modes vary—support system (grid, space frame) failure taking the skylight with it, or intact supports with skylight damage from inadequate connections or compression resistance. Design must ensure reliable connections and deformation capacity.
Air tightness: Sealed skylights require strict air infiltration control—critical for air-conditioned buildings.
Water tightness: Ability to prevent rainwater penetration under combined wind and rain or melting snow. Interior condensation is a common problem—roof slope must shed water rather than drip. Collect condensate via drainage channels to the exterior; perform condensation calculations in design.
Thermal insulation: Resistance to heat transfer across temperature differences and re-radiation of absorbed solar heat varies by glass type—reflective coated, single float, insulating, reflective insulating, polycarbonate, acrylic, etc. Also consider sound insulation, fire design, hail impact, and lightning protection.
Glass skylight roofs are specialized, complex technology. Though small in building area, requirements are strict. "Nine out of ten glass roofs leak (including condensation)" often results from underestimating design and construction. Skylight construction integrates structural design, building physics, MEP, and site conditions—a comprehensive discipline requiring balanced aesthetics, safety, advanced technology, and economy.
