Post 375 – by Gautam Shah
Ceiling are floor underside treatment systems.
Major varieties are:
1 Coating applied to the floor bottom,
2 Screed like spread over a lath or lattice hung at a distance from floor,
3 Pre-formed stiff panels fixed to the grid,
4 Flexible sheets stretched across the structural elements.
The coating or plaster like surface treatment creates a smooth surface that regulates the visual character. Plaster ceilings reduce and condition the volumetric form of the space. It covers unsightly elements like joists, beams, trusses, ducts and other services. Plaster ceilings and adjunct cornices add patterns. The coating, if of porous or foamed mass, increases the noise absorption and provides thermal insulation.
Screed like spreads are applied over a lath or lattice, hung at a distance from the floor bottom. The lath or lattice is formed of wire or synthetic net, woven mat, or expanded sheet metal lattices. The distance between the lattices and floor allows concealing of beams, joists, and services like cables. The screed over the lath levels out the ceiling surface. The screed materials consist of gypsum, mud or high-body polymeric substances. The process of application is slow and labourious, but uses rudimentary technology. The ceiling surface is not consistent everywhere, causing unpredictable behaviour at spots.
Pre-formed stiff panels fixed to the grid provide faster installation with reasonably consistent quality of materials. The panels are precast on the site or purchased as ready-made tiles. The joints need to be covered with reinforcing tape of paper or synthetic material or left a groove. The grid to fix the panel need to be matched with the panel sizes. Extra light panels (of expanded materials) have ready-finished edges that can be revealed, grooved or finished ‘flushed’. Such ready panels or ceiling tiles need to have a balanced layout, where the residues are divided equally on both sides of length and width of the room. Provision of ceiling light fixtures, smoke detectors, fire sprinklers, and accommodation of partitions and columns with the ceiling grid layout is difficult design exercise. Ceilings with tiles where joints are revealed are not ideal for circular or non-square askew spaces and small rooms.
Flexible sheets stretched across the structural elements are created to add spatial interest at ceiling level. The Flexible sheets of fabrics, Rexine, leather, paper, plastics and their composites are used in free forming tensile form. These materials yield a lot, so need frequent resetting. Inverse half-drums, parabolic curves, etc., are formed. Such ceiling forms were once created over royal thrones and canopy beds.
Ceilings mainly help modulate a space. The form, texture, pattern, and colour all are exploited for the purpose. Ceilings impose a design discipline more effectively than flooring could do. Floors are likely to be clustered with furniture and furnishings, but ceilings are comparatively less occupied. Ceilings have two types of modulations: First regulation is through the form, and the Second one is through the patterns that emerge through tonal variations through colour, texture, and illumination. The texture over the surface is crafted and also formed by the joints.
The ceiling (materials) and its form, both, are used in defining the architectural and functional characteristics of the space. Ceilings help in the noise absorption in areas like corridors, lobbies, public rooms, class rooms, auction rooms, markets, and nursery rooms. In some areas ceilings help deflect or divert noise as in under ground railway stations, open air performance stages, amphi theatres. Ceilings of high acoustic efficiency are required in airport lounges, textile loom sheds, drop-forging machines, railway carriages, cars, underground railway platforms, buildings on busy road junctions, hospitals’ critical care areas, prayer and meditation rooms, court rooms and recording studios. Ceilings are required to control the reverberated sounds in places like cinema halls, assembly rooms, auditoriums, recording studios, broadcasting halls etc. Ceilings of special shapes and materials over the stage front face help in propagating the sound towards the audience. Ceilings in shops, living rooms etc. create dramatic effects, accentuate areas of interest, provide a novelty in vistas. Ceilings in the climate controlled areas provide the required thermal insulation and reduce the over all volume of space to be handled. In laboratories and other technical areas ceilings cover service lines. The shape and configuration of the ceiling help in controlling the quality, intensity and distribution pattern of light. Ceilings by their shape and level create a variety of psychological effects.