Curtain Wall Systems — Unitised, Semi-Unitised and Conventional
A curtain wall is a glazed building facade built in one of three configurations: unitised, with panels assembled in the factory; conventional stick, assembled piece by piece on site; or semi-unitised, which combines site-erected framing with factory-prepared infill. The choice depends on building height, panel repetition, crane access and programme.
By Dhruv Agarwal · · 2 min read
What we deliver
Curtain wall in all three configurations — unitised, semi-unitised and conventional stick — engineered, fabricated and installed as one accountable package rather than split between a designer, a fabricator and an installer.
The system choice is made on evidence at survey stage. Building height, panel repetition, crane availability and programme all point to a different answer, and the wrong choice is expensive to reverse once brackets are set.
Facade leadership experience
Our Director – Facade, Akhilesh Kumar Singh (25+ years in facade engineering), has led delivery on projects including:
| Project | Location | Scope | Quantity |
|---|---|---|---|
| DLF — Building 8 | Cyber City, Gurgaon | Stick curtain wall glazing, aluminium solid sheet, Galvalume & Shera board cladding | 14,175 sq. m. |
| Broadway Service Apartment | Dwarka Expressway, Sector 83, Gurugram | Curtain wall glazing & aluminium doors and windows | 10,550 sq. m. |
| Anygraphics Factory | Noida, Uttar Pradesh | Semi-unitised structural glazing, PIR panel, rock wool panel | 6,500 sq. m. |
Scope of works
| Stage | What we deliver |
|---|---|
| Survey & assessment | Measured survey, slab edge condition, system recommendation |
| Design & engineering | Wind load analysis to IS 875 Pt 3, shop drawings, bracket design |
| Mock-up & testing | Visual approval, ASTM E283 / E331, structural loading, water re-test |
| Fabrication | In-house cutting, routing, crimping, end milling, in-process inspection |
| Installation | Setting out, bracket fixing, panel erection, sealing |
| Testing & handover | Site water testing, snagging, O&M documentation |
What drives the cost
Height and access strategy · panel repetition across the elevation · glass specification (SHGC, U-value, DGU build-up) · framing depth set by wind pressure · whether the facade is unitised or stick · corner and setting-out complexity · programme compression.
Where projects go wrong
- System chosen before the survey. Slab edge tolerance and crane access frequently rule out the system that was assumed at concept.
- Ordering before the mock-up is signed off. Once production starts, a change means re-tooling.
- Structural glazing bite copied from another project. Wind pressure is building-specific; corner and upper-floor panels need more than the average.
- Spandrel treated as an afterthought. The cavity behind runs far hotter than the vision area and needs heat-strengthened glass and insulation behind it.
Why Hagerstone
100% in-house execution under a Director — Facade with 25+ years in facade engineering, structural glazing and high-rise exterior work, supported by a dedicated 20-member facade team.
79+ quality checkpoints, in-process inspection and sign-off before despatch, under ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 certification.
One accountable partner — facade coordinated with interiors, MEP, civil and PEB rather than split across vendors who each blame the other at the interface.
Standards referenced
Wind loading to IS 875 (Part 3). Air and water performance verified to ASTM E283 and ASTM E331. Quality management to ISO 9001:2015.
Standards referenced
- IS 875 (Part 3) — Wind loads on buildings (Bureau of Indian Standards)
- ASTM E283 / E331 — Air infiltration and water penetration (ASTM International)
- ISO 9001:2015 — Quality management (ISO)
Frequently asked
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