Glass, Plastics, Cladding & Finishes
The materials of the modern envelope — and the finishes that complete it.
The modern building's skin is made of glass and plastics, hung as cladding and curtain walls, and finished with flooring and paint. Learn the glass family and when safety glass is required, plastics from thermoplastic to thermoset, the cladding systems and the curtain wall, and the everyday finishes that complete a building — the materials that turn a structure into architecture.
Learning objectives
By the end of this lesson, you will be able to — mapped to the course outcomes for Design of Structures I:
Identify the types of glass and where safety glass is required (IS 16231).
Distinguish thermoplastic and thermoset plastics and their building uses.
Describe cladding systems, the curtain wall and structural glazing.
Select appropriate flooring and painting for a situation.
Glass and plastics
Float glass is the base; toughened and laminated are the safety glasses; insulated units and low-E coatings cut heat (IS 16231). Plastics split into thermoplastic (remeltable) and thermoset (permanently cured), with membranes like ETFE spanning huge roofs.[1, 2, 3]
Float and beyond
Float (annealed) glass — molten glass floated on tin — is the base product, breaking into sharp shards. Toughened glass is heat-strengthened and breaks into blunt granules (a safety glass); laminated glass holds together on a plastic interlayer; wired glass gives fire integrity (but is not impact-safe); the insulated glass unit (IGU) and low-E coatings cut heat. IS 16231 governs the use of glass in buildings.[1, 2]
| Glass type | What it is | Key use |
|---|---|---|
| Annealed (float) | The basic float glass, cooled normally; breaks into large sharp shards. | General windows where safety glass is not required. |
| Toughened (tempered) | Heat-strengthened; shatters into small blunt granules — a safety glass. | Doors, low-level glazing, shower screens, façades. |
| Laminated | Two or more panes bonded by a plastic interlayer; fragments stay stuck on breakage. | Overhead glazing, security, acoustic and safety-critical positions. |
| Wired | Wire mesh rolled into the ribbon; holds together in fire (but NOT a high-impact safety glass). | Fire-integrity glazing. |
| IGU / double glazing | Two or more panes with a sealed spacer cavity, often gas-filled. | Thermal and acoustic insulation in windows and façades. |
| Low-E / reflective | A coating that reflects long-wave heat and UV while passing visible light, or cuts solar gain and glare. | Solar-control, energy-efficient façades. |
Cladding, façades and finishes
Cladding (stone, ACP — specify a fire-rated core — timber) is the non-structural skin; the curtain wall is a hung façade (stick vs unitised); structural glazing hides the mullions; and flooring and painting finish the surfaces.[4, 5]
Stone, ACP, timber
Cladding is the non-structural outer skin: thin stone slabs on anchors; aluminium composite panels (ACP) — light and flat, but specify a fire-rated (mineral) core, as ordinary polyethylene-core ACP is combustible; and timber boards over a ventilated cavity. Cladding finishes; it does not carry building loads.[4, 5]
At a glance
| Aspect | One | The other |
|---|---|---|
| Two safety glasses | Toughened: granulates safely on impact | Laminated: holds together on the interlayer |
| Two plastics | Thermoplastic: remelts, recyclable, flexible | Thermoset: cures permanently, harder, heat-resistant |
| Two curtain walls | Stick: site-assembled, flexible, slower | Unitised: factory panels, faster on site |
| Façade systems | Curtain wall: framed, mullions visible | Structural glazing: silicone-bonded, no external mullions |
| ACP caution | FR / mineral core: improved fire performance | Plain PE core: combustible — a fire risk |
Key terms
Flat glass made by floating molten glass on molten tin — the base 'annealed' product.
Heat-strengthened safety glass that breaks into small blunt granules.
Panes bonded by a plastic interlayer; fragments adhere on breakage.
A sealed multi-pane unit with a spacer cavity for thermal/acoustic insulation.
A non-load-bearing façade hung off the structure, carrying only self-weight + wind/seismic.
Glass bonded to its frame with structural silicone — no external mullions.
Aluminium composite panel — two aluminium skins over a core; use a fire-rated core.
Remeltable, recyclable plastics vs permanently-cured, harder ones.
Crushed-aggregate flooring set in a cement or epoxy matrix, ground and polished.
Water-based acrylic/vinyl paint — durable, washable, the common interior wall finish.
Studio task
For a small office façade, specify the glass (type and where safety glass is required), choose between a curtain wall and structural glazing, and pick a flooring and a paint system for the lobby — justifying each in one line.
Self-assessment
1. Which glass holds together via a plastic interlayer when broken?
2. A curtain wall is best described as —
3. The fire-safety caution with ACP cladding is that —
Recap
References & further reading
- [1]Float glass and glass types — the Pilkington process and processed glasses.
- [2]IS 16231 — Use of Glass in Buildings (Parts 1–4), and IS 2553 (safety glass). Bureau of Indian Standards. (Supersedes the earlier IS 7883 draft.)
- [3]R.M. Davis, Plastics in Building Construction; Arthur Lyons, Materials for Architects.
- [4]Curtain walls and structural glazing — stick vs unitised systems (façade-industry references).
- [5]S.K. Duggal, Building Materials; Chudley & Greeno, Building Construction Handbook (cladding, flooring, painting).
Further reading
- S.K. Duggal, Building Materials — glass, plastics, finishes.
- Arthur Lyons, Materials for Architects and Builders.
- Roy Chudley & Roger Greeno, Building Construction Handbook.
Sources gathered and fact-checked June 2026. Published values vary by source, sample and method — treat as indicative and confirm against the cited standard before structural use.