Glass brick

Last updated
Sidewalk skylight (also named 'pavement light') made of load-bearing glass bricks in Burlington House, London BurlingtonHousePavementWindow.jpg
Sidewalk skylight (also named 'pavement light') made of load-bearing glass bricks in Burlington House, London

Glass brick, also known as glass block, is an architectural element made from glass. The appearance of glass blocks can vary in color, size, texture and form. Glass bricks provide visual obscuration while admitting light. The modern glass block was developed from pre-existing prism lighting principles in the early 1900s to provide natural light in manufacturing plants. Today glass blocks are used in walls, skylights, and sidewalk lights.

Contents

Attributes

Appearance

The texture and color of glass blocks can vary in order to provide a range of transparency. Patterns can be pressed into either the inner void or the outside surface of the glass when it is cooling in order to provide differing effects. Glazes or inserts may also be added in order to create a desired private or decorative effect.

Standards and grading

Glass blocks in Europe are manufactured in accordance with the European Standard EN1052-2. The International Standard is ISO TC 160/SG1. The Standards allow for variation in sizes and production irregularity. Blocks fall within three classifications; Class 1, Class 2 and Class 3 with Class 1 being the highest and best rating with a maximum permissible deviation from designed size and rectangularity of 1 mm.

Insulation

Glass brick has an r value between 1.75 and 1.96, close to that of thermopane windows. [1] [2] There are newer glass blocks injected with argon gas and having a layer of low-emissivity glass between the halves, which increases the insulative (U) value to 1.5 W/m2·K, which is between triple glazed windows (1.8 W/m2·K) and specialty double glazed windows with advanced frame and coatings(1.2 W/m2·K). [3]

Applications

Wall blocks

Glass block wall in Chicago. Glass block wall.jpg
Glass block wall in Chicago.

Glass blocks can provide light and serve as a decorative addition to an architectural structure, but hollow glass blocks are non load-bearing unless stated otherwise. Hollow glass wall blocks are manufactured as two separate halves and, while the glass is still molten, the two pieces are pressed together and annealed. The resulting glass blocks will have a partial vacuum at the hollow center. Due to the hollow center, wall glass blocks do not have the load-bearing capacity of masonry bricks and therefore are utilized in curtain walls. [4] Glass block walls are constrained based on the framing in which they are set. If a masonry or steel frame exists, the maximum area of the wall can be 144 square feet (13.4 m2), whereas the maximum area without a frame is 100 square feet (9.3 m2). [5]

The William Lescaze House and Office at 211 East 48th Street in New York City, built in 1934, was the city's first house to use glass blocks as walls. [6]

Skylights and sidewalk lights

Glass blocks used in flooring are normally manufactured as a single solid piece, or as a hollow glass block with thicker side walls than the standard wall blocks. These blocks are normally cast into a reinforced concrete gridwork or set into a metal frame, allowing multiple units to be combined to span over openings in basements and roofs to create skylights. Glass wall blocks should not be used in flooring applications because the way in which they are manufactured does not allow them to support a load.

Construction methods

Glass wall blocks are fixed together to form complete walls by several methods – the most common method of construction is to bed the blocks together in a Portland cement-based mortar with reinforcing rods of steel placed within the mortar as recommended by the project architect or block manufacturer.

Other methods of construction include several proprietary systems whereby the mortar is replaced by timber or PVC extrusions.

Specialty types

Specialist glass blocks are produced for various applications including:

Bullet and vandal resistance

Bullet and vandal resistant blocks are generally solid glass or have very thick side walls similar to pavement blocks.

Fire resistant

Fire resistance of varying degrees can be achieved by several methods. Standard production hollow wall block will offer little fire resistance; however, resistance is improved by utilizing specially produced hollow blocks with thicker sidewalls, or the inclusion of a special layer of fire-resisting material between the two halves of the block during manufacture. Some manufacturers of glass blocks have developed a method of bonding two glass blocks together with adhesive, producing blocks of up to 160 mm (6½") thick with enhanced fire resistance. It is important that the block manufacturer's recommendations are followed with regards to the installation of fire resisting glass block walls, as without special construction techniques, the wall will not achieve the desired fire resistance.

Gas insulated

A recent innovation in the manufacture of glass blocks is the inclusion of argon gas within the hollow center of glass wall blocks. This advancement in production technique has resulted in a glass block which is able to offer significantly improved thermal insulation properties.

Colored

Some hollow glass wall blocks are available in colored variants. These colored variants fall into two categories. The first type is manufactured with UV stable colored glass and can be used in the same locations as standard clear glass blocks. The second type utilizes a colored material (dye or transparent paint) which is injected into the hollow center of the blocks to form a permanent coating, enabling vibrant colors to be achieved which are not possible with colored glass. However, the colored coating may not be UV stable and can fade in bright sunshine over time, and may therefore not be suitable for all locations.

19th century precursors

Falconnier

Modern glass bricks were preceded by Falconnier Hollow Glass Bricks in the late nineteenth century. Falconnier Bricks were blown glass bricks available in multiple colors and were formed in molds while the glass was molten. [7] They could be used for walls or roofs and were joined with wire and cement. The suggested use for Falconnier glass bricks was in greenhouse construction due to the non-conductivity of the glass for temperature control and lack of porosity of glass for moisture control. They were touted for not tarnishing, trapping dust, or retaining water.

Prisms

Vault lights in sidewalks, which utilized prism lighting, were one of the first steps towards the modern hollow glass brick. At the end of the nineteenth century glass prisms became a popular way to diffuse light into spaces that would otherwise be difficult or unsafe to light via flame-based oil lamps (e.g. basements underneath sidewalks). [8]

Examples of architectural use

See also

Related Research Articles

<span class="mw-page-title-main">Adobe</span> Building material of earth and organic materials

Adobe is a building material made from earth and organic materials. Adobe is Spanish for mudbrick. In some English-speaking regions of Spanish heritage, such as the Southwestern United States, the term is used to refer to any kind of earthen construction, or various architectural styles like Pueblo Revival or Territorial Revival. Most adobe buildings are similar in appearance to cob and rammed earth buildings. Adobe is among the earliest building materials, and is used throughout the world.

<span class="mw-page-title-main">Brick</span> Block or a single unit of a ceramic material used in masonry construction

A brick is a type of construction material used to build walls, pavements and other elements in masonry construction. Properly, the term brick denotes a unit primarily composed of clay, but is now also used informally to denote units made of other materials or other chemically cured construction blocks. Bricks can be joined using mortar, adhesives or by interlocking. Bricks are usually produced at brickworks in numerous classes, types, materials, and sizes which vary with region, and are produced in bulk quantities.

<span class="mw-page-title-main">Masonry</span> Building of structures from individual units of stone, bricks, or blocks

Masonry is the craft of building a structure with brick, stone, or similar material, including mortar plastering which are often laid in, bound, and pasted together by mortar. The term masonry can also refer to the building units themselves.

<span class="mw-page-title-main">Wall</span> Vertical structure, usually solid, that defines and sometimes protects an area

A wall is a structure and a surface that defines an area; carries a load; provides security, shelter, or soundproofing; or, is decorative. There are many kinds of walls, including:

<span class="mw-page-title-main">Daylighting (architecture)</span> Practice of placing openings and reflective surfaces so that sunlight can provide internal lighting

Daylighting is the practice of placing windows, skylights, other openings, and reflective surfaces so that direct or indirect sunlight can provide effective internal lighting. Particular attention is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy use. Energy savings can be achieved from the reduced use of artificial (electric) lighting or from passive solar heating. Artificial lighting energy use can be reduced by simply installing fewer electric lights where daylight is present or by automatically dimming or switching off electric lights in response to the presence of daylight – a process known as daylight harvesting.

<span class="mw-page-title-main">Tile</span> Manufactured pieces for covering surfaces

Tiles are usually thin, square or rectangular coverings manufactured from hard-wearing material such as ceramic, stone, metal, baked clay, or even glass. They are generally fixed in place in an array to cover roofs, floors, walls, edges, or other objects such as tabletops. Alternatively, tile can sometimes refer to similar units made from lightweight materials such as perlite, wood, and mineral wool, typically used for wall and ceiling applications. In another sense, a tile is a construction tile or similar object, such as rectangular counters used in playing games. The word is derived from the French word tuile, which is, in turn, from the Latin word tegula, meaning a roof tile composed of fired clay.

<span class="mw-page-title-main">Building material</span> Material which is used for construction purposes

Building material is material used for construction. Many naturally occurring substances, such as clay, rocks, sand, wood, and even twigs and leaves, have been used to construct buildings and other structures, like bridges. Apart from naturally occurring materials, many man-made products are in use, some more and some less synthetic. The manufacturing of building materials is an established industry in many countries and the use of these materials is typically segmented into specific specialty trades, such as carpentry, insulation, plumbing, and roofing work. They provide the make-up of habitats and structures including homes.

<span class="mw-page-title-main">Curtain wall (architecture)</span> Outer non-structural walls of a building

A curtain wall is an exterior covering of a building in which the outer walls are non-structural, instead serving to protect the interior of the building from the elements. Because the curtain wall façade carries no structural load beyond its own dead load weight, it can be made of lightweight materials. The wall transfers lateral wind loads upon it to the main building structure through connections at floors or columns of the building.

<span class="mw-page-title-main">Fireproofing</span> Rendering something (structures, materials, etc.) resistant to fire, or incombustible

Fireproofing is rendering something resistant to fire, or incombustible; or material for use in making anything fire-proof. It is a passive fire protection measure. "Fireproof" or "fireproofing" can be used as a noun, verb or adjective; it may be hyphenated ("fire-proof").

<span class="mw-page-title-main">Architectural glass</span> Building material

Architectural glass is glass that is used as a building material. It is most typically used as transparent glazing material in the building envelope, including windows in the external walls. Glass is also used for internal partitions and as an architectural feature. When used in buildings, glass is often of a safety type, which include reinforced, toughened and laminated glasses.

<span class="mw-page-title-main">Tempered glass</span> Type of safety glass processed to increase its strength

Tempered or toughened glass is a type of safety glass processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Tempering puts the outer surfaces into compression and the interior into tension. Such stresses cause the glass, when broken, to shatter into small granular chunks instead of splintering into large jagged shards as ordinary annealed glass does. These smaller, granular chunks are less likely to cause deep penetration when forced into the surface of an object compared to larger, jagged shards because the reduction in both the mass and the maximum dimension of a glass fragment corresponds with a reduction in both the momentum and the penetration depth of the glass fragment.

Thermal transmittance is the rate of transfer of heat through matter. The thermal transmittance of a material or an assembly is expressed as a U-value. The thermal insulance of a structure is the reciprocal of its thermal transmittance.

<span class="mw-page-title-main">Architectural terracotta</span> Fired clay construction material

Architectural terracotta refers to a fired mixture of clay and water that can be used in a non-structural, semi-structural, or structural capacity on the exterior or interior of a building. Terracotta is an ancient building material that translates from Latin as "baked earth". Some architectural terracotta is stronger than stoneware. It can be unglazed, painted, slip glazed, or glazed.

<span class="mw-page-title-main">Glazing (window)</span> Part of a wall or window, made of glass

Glazing, which derives from the Middle English for 'glass', is a part of a wall or window, made of glass. Glazing also describes the work done by a professional "glazier". Glazing is also less commonly used to describe the insertion of ophthalmic lenses into an eyeglass frame.

<span class="mw-page-title-main">Insulated glazing</span> Construction element consisting of at least two glass plates

Insulating glass (IG) consists of two or more glass window panes separated by a space to reduce heat transfer across a part of the building envelope. A window with insulating glass is commonly known as double glazing or a double-paned window, triple glazing or a triple-paned window, or quadruple glazing or a quadruple-paned window, depending upon how many panes of glass are used in its construction.

<span class="mw-page-title-main">Structural clay tile</span> Class of building block

Structural clay tile describes a category of burned-clay building materials used to construct roofing, walls, and flooring for structural and non-structural purposes, especially in fireproofing applications. Also called building tile, structural terra cotta, hollow tile, saltillo tile, and clay block, the material is an extruded clay shape with substantial depth that allows it to be laid in the same manner as other clay or concrete masonry. In North America it was chiefly used during the late 19th and early 20th centuries, reaching peak popularity at the turn of the century and declining around the 1950s. Structural clay tile grew in popularity in the end of the nineteenth-century because it could be constructed faster, was lighter, and required simpler flat falsework than earlier brick vaulting construction.

<span class="mw-page-title-main">Skylight</span> Window in the ceiling-roof

A skylight is a light-permitting structure or window, usually made of transparent or translucent glass, that forms all or part of the roof space of a building for daylighting and ventilation purposes.

<span class="mw-page-title-main">Pavement light</span> Flat-topped skylights designed to be walked on

Pavement lights (UK), vault lights (US), floor lights, or sidewalk prisms are flat-topped walk-on skylights, usually set into pavement (sidewalks) or floors to let sunlight into the space below. They often use anidolic lighting prisms to throw the light sideways under the building. They were developed in the 19th century, but declined in popularity with the advent of cheap electric lighting in the early 20th. Older cities and smaller centers around the world have, or once had, pavement lights. In the early 21st century, such lights are approximately a century old, although lights are being installed in some new construction.

<span class="mw-page-title-main">Prism lighting</span> Use of prisms to improve lighting

Prism lighting is the use of prisms to improve the distribution of light in a space. It is usually used to distribute daylight, and is a form of anidolic lighting.

<span class="mw-page-title-main">Lescaze House</span> House in Manhattan, New York

The Lescaze House is a four-story house at 211 East 48th Street in the East Midtown and Turtle Bay neighborhoods of Manhattan in New York City. It is along the northern sidewalk of 48th Street between Second Avenue and Third Avenue. The Lescaze House at 211 East 48th Street was designed by William Lescaze in the International Style between 1933 and 1934 as a renovation of a 19th-century brownstone townhouse. It is one of three houses in Manhattan designed by Lescaze.

References

  1. Archived November 27, 2013, at the Wayback Machine
  2. "Glass Block Sales, Inc". Glassblocksales.com. Archived from the original on 2016-03-04. Retrieved 2016-02-01.
  3. "Glass Block Q19 Energy Savings Technology Lines" . Retrieved 2016-10-12.
  4. Brantley, L. Reed; Brantley, Ruth T. (1995). Building Materials Technology. New York: McGraw-Hill Inc. p. 111. ISBN   0-07-007265-5.
  5. Hornbostel, Caleb (1978). Construction Materials: Types, Uses, and Applications. New York: John Wiley & Sons.
  6. Devin Gannon (26 April 2018). "Landmarked William Lescaze House, the first modern residence in NYC, asks $5M". 6sqft.com. Retrieved 13 February 2019.
  7. "Building Bricks of Glass". Carpentry and Building (1879–1909). 1: 206. June 1, 1909.
  8. De Vis, Krystal; Jacobs, Patric; Caen, Joost; Janssens, Koen (October 2010). "The Use of Glass Bricks in Architecture in the 19th and 20th Centuries: A Case Study". Glass & Ceramics Conservation: 194–201.