For many centuries now, glass has been a material that has been used in buildings for a diverse range of applications. Its unique properties have made it a difficult material to replace even with the advanced technologies adopted in the modern Architecture, Engineering and Construction (AEC) industry. Keep reading to understand all about glass as a construction material, how it’s made, properties of glass, types of glass and uses of glass material in buildings.
What is Glass?
Glass is an inorganic material that is formed by cooling a mixture of materials like limestone, sand and soda ash. Although many forms of glass material are naturally occurring (such as obsidian glass, which is formed by the cooling of volcanic lava), it is most often manufactured in factories for use in construction and other industries. Glass as a construction material is known for its transparency, which enables the transmission of maximised natural light in enclosed spaces.
How is Glass Made?
Glass production follows the below steps:
- Mixing of Raw Materials: The main components involved in making glass are silica sand, limestone, soda ash and recycled glass. These materials are weighed and mixed together in the right proportions in a batch mixer or furnace.
- Melting: The raw materials are heated to a temperature of around 1500°C – 1600°C, forming a molten mixture.
- Moulding: The molten mixture is poured into different kinds of moulds to obtain the required glass shape. For example, flat glass is produced by the ‘float glass process’, which involves pouring the molten glass onto a tin bath and then passing it through rollers. A process of ‘glassblowing’ is used to produce other shapes and forms, in which the glass is inflated into bubbles and then blown into the right shape by moulding, rolling or swinging processes.
- Finishing: Once the desired shape is achieved, the glass is slowly cooled down to room temperature. For flat and plain glass, the top surface is subjected to Nitrogen under pressure to obtain a smooth polished finish. Other finishes may involve applying laminates, colour coatings or strengthening as required for the glass building material.
Properties of Glass as a Construction Material
Glass for building is generally known to possess the following characteristics:
- Transparency: Conventional glass has one of the highest transmittance values, meaning that it can allow the maximum amount of light to pass through itself. However, its properties can be modified to make it translucent, opaque, coloured or transparent on only one side, as required.
- Strength: Normal glass is generally brittle and can break easily upon impact. However, the inclusion of admixtures and specific chemicals helps create stronger types of glass, such as structural glass, toughened glass and bulletproof glass.
- Heat Transfer: Glass buildings lead to increased amounts of heat transfer into spaces, negatively affecting the indoor thermal comfort. While often increasing the need for mechanical ventilation systems inside buildings, such structures can also enhance the greenhouse effect by trapping heat in the atmosphere.
- Recyclability: Glass blocks, sheets and all other forms of glass are completely recyclable. They can be reduced to their molten form and remoulded into any shape as desired, thus enhancing construction waste management techniques.
- Finish and Workability: Most types of glass for construction can be easily cut, shaped and finished (with paints, polishes, laminates, etc.) on-site. Available in multiple shapes, finishes, thicknesses, colours and strength, glass as a construction material is extremely versatile.
Types of Glass in Building Construction
Various types of glass are available in the market today with distinct properties. However, the major types based on the way they are manufactured are:
Annealed Glass
Annealed glass, float glass or flat glass is the most basic type of glass produced during manufacturing. In the ‘float glass process’, the molten glass is allowed to cool down very slowly, until it obtains adequate strength without cracking and until it reaches room temperature. This glass is used to form other types with more advanced properties and strength.
Heat Strengthened Glass
Annealed glass is heated up again to a temperature of around 600°C – 700°C and then cooled down quickly. This reheating process produces glass that has twice the mechanical and thermal strength of annealed glass. Although heat-strengthened glass has higher strength, it cannot be used for structural applications, but is used in external doors, windows and other spaces which require more strength than normal glass.
Toughened Glass
Also called tempered glass, toughened glass is also formed by reheating annealed glass to a temperature of around 600°C – 700°C. However, the cooling process involves subjecting the glass to a blast of air and is much faster. The resultant glass is 4-5 times stronger than annealed glass and can be used for structural applications in modern glass buildings.
Uses of Glass in Architecture
The uses of glass as a construction material are diverse and some of the main ones are:
Structural Uses of Glass
- Glass Walls (Structural Glazing): Toughened and high-density glass can be used to form load-bearing walls that have a modern, clean aesthetic.
- Glass Roofs and Skylights: Glass roofs and skylights allow maximum natural light penetration, which is especially beneficial for houses in tight plots or large commercial buildings with minimal windows.
- Glass Floors: With enhanced visibility across different levels, glass floors act as an aesthetic element in modern offices, shopping centers and other commercial spaces.
Glass is also used to form other composite materials like glass fibre reinforced concrete, reinforced glass panels, fiberglass material and glass reinforced plastics, which also have numerous structural applications in construction.
Non Structural Uses of Glass
Glass can be used to make the following non-structural components in buildings:
- Doors, windows and other openings that transmit light.
- Exterior glass walls or curtain walls and interior partitions.
- Staircase components like glass railings, balustrades, landings, risers and treads.
- Furniture products like tables, storage cabinets and display units.
- Glasswool or fibreglass insulation to improve energy efficiency.
- Elements like solar panels that need to absorb heat.
Using Glass as a Construction Material in Your Project
Glass structures are very common and popular in modern architecture. Using the right type of glass can ensure that a building is functional, durable and energy efficient. Brick & Bolt, a leading tech-enabled construction company in India, joins hands with the top brands and manufacturers to ensure the best building materials supply, including glass products. The company’s end-to-end construction construction services are aided by skilled architectural design, expert execution and 470+ quality checks for every project. To use glass as a construction material and ensure that your project is completed by experts in the field, get in touch with Brick & Bolt today!
Apoorva H P Achar 
Hemali Patel