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A facade is the outer building envelope or visible external wall of a building. It protects against weather, shapes the building’s appearance and influences energy efficiency, indoor climate and acoustics. Structurally, it may be designed as a curtain wall, punched-window facade, mullion-transom system, ETICS or ventilated rainscreen cladding.
Why is the facade important?
- Energy and comfort: Thermal insulation, airtightness and summer heat protection reduce energy consumption and improve the indoor climate.
- Protection and durability: Weather protection, fire protection and sound insulation help secure function and long-term performance.
- Value and design: Material, structure and detailing shape the architecture and the property value.
- Renovation effect: Facade measures such as facade insulation, window replacement and sealing can deliver measurable savings and may be relevant for funding or subsidy documentation.
Facade in practice: structure and renovation
- Condition survey: Digital measurement using LiDAR or photogrammetry, thermography to detect thermal bridges and leaks, and documentation of connection details and moisture damage.
- Analysis: U-value calculation, material condition, fixings and load-bearing capacity, moisture paths, and alignment with fire protection and sound insulation requirements.
- Measure planning: Selection of the facade system, such as ETICS, ventilated rainscreen facade, mullion-transom system or window replacement/upgrade, including details for junctions and airtightness.
- Implementation: Qualified installation, minimisation of thermal bridges, verified sealing and fixing details, and quality assurance with measurement and inspection records.
- Documentation: Update as-built or existing condition plans, store documentation such as thermography and, where applicable, blower door test results, and add maintenance instructions.
Facade types
- ETICS (External Thermal Insulation Composite System): External insulation with a render system. Efficient and economical.
- Ventilated rainscreen facade: Cladding or facade covering installed on a substructure with rear ventilation. Robust, versatile and effective for moisture management.
- Mullion-transom / glass facade: High daylight levels; requires a concept for solar shading, thermal protection and sound insulation.
- Punched-window facade: Solid construction with individual openings, usually windows. Flexible in renovation projects.
- Unitized facade: Prefabricated modules, short construction time and high quality assurance.
Common mistakes and misunderstandings
- Only optimising insulation thickness: Junctions, airtightness and thermal bridges are just as important.
- Underestimating condensation and moisture: Missing rear ventilation or inadequate sealing can lead to damage.
- Wrong level of detail: Overplanning or underplanning connection points such as windows, parapets and base details can cause defects.
- No quality assurance: Without documented measurements, such as thermography, defects may remain undetected.
- Media breaks: Paper-based measurements and sketches create information losses. Digital workflows help ensure completeness.
Facade vs. building envelope
- Building envelope: The complete separating system, including roof, external walls, windows, doors and ground slab.
- Facade: The vertical external wall area, including openings and cladding. It is part of the building envelope.
FAQ
Which facade systems are suitable for energy-efficient renovation?
ETICS is often used because it is economical. A ventilated rainscreen facade is suitable where high robustness, moisture protection or suspended cladding materials are required. Anyone planning to renovate a facade should decide based on building physics, design and budget.
How can I identify thermal bridges on the facade?
Thermal bridges can be identified through thermography and a detailed inspection of junctions. The results inform measures such as insulation wedges, thermally separated fixings and airtight connections.
What should facade documentation include?
Facade documentation should include current plans or as-built drawings, connection details, material and system documentation, inspection records such as thermography, and maintenance instructions.