Post by Gautam Shah 

Thin shell roof

Roof and floor systems are called elements mediating across the load-bearing systems, such as walls and beams. Roofs by themselves may transmit the load, such as in Flat slabs, Shell structures, Domes, etc. Roofs can take various shapes, but Floors are flatter and only occasionally slightly inclined. The distinction of floor and beam or wall may or may not be very apparent. In some structures both are well integrated, so act coherently (e.g. waffle slabs). In other structures the identity of each is distinct yet they may operate interdependently. In assembled structures the components are independent, and easy to identify (a stone plate on a wall is simply supported). In cases where the structural support system and covering elements are integrated, the stress transfer is very efficient. This also results into a system that is lean and lightweight, when compared to system of independent (simply supported) components.

Frank Lloyd Wright Johnson Wax building Flat slab roof

Covering elements in Compressive roof systems are composed of stiff materials. These elements have a comparatively substantial thickness in proportion to the span. The thickness requirements vary depending on the composition of structure and the stress resistance of the material, the shape configuration of the covering element, the mode of stress transfer (across or along the section) and the end (support) conditions.

Brick vaulting

Covering elements in Tensile roofing systems are composed of stiff or flexible materials. The later have very small thickness in comparison to the size of the span. The material being very thin and flexible takes on the shape the way it is stressed to, and also depending on the gravity induced stress forms (catenary). Covering elements of a roofing system, when pre-stressed (usually pre-stretched), show greater resistance to various stresses.

Air inflated dome

For predominantly compressive elements, the shear capacity increases several fold. For tensile elements, the capacity to deal with local loads increases.


Covering material may be a homogeneous mass, a composition of smaller units or a layered mass. Covering materials in a roofing system are wood planks (shingles), plywood, laminated paper composites, fibre bitumen composites, fibre cement composites, ceramics, stones (slates, marbles, metamorphic rocks), glass, fibre-glass, cast in situ and pre-cast RCC, hollow blocks of cement and terracotta, cellular blocks, air entrained or expanded foam blocks, plastics, plastic foams, metal and alloy sheets, leaves, grass, sticks, natural fibres, mats, textiles, wool, synthetic woven materials, tarpaulins, impregnated fabrics, clay blocks, bricks, ice, ferro and magnesium cement castings, rubber sheets, nylon, Teflon, etc.

Crystal Palace -Glass roof-wall building

Louvre Paris Glass Pyramids as extension

A transparent roof cover material that would allow light and permit vision through was a dream, that every builder tried to realize. Romans used small glass disks inserts for roof illumination. Gothic period saw tall perpendicular windows almost merging into the roof. Paintings and murals with extensive skies as the theme were painted on the ceilings. However, it was the Conservatory at Derbyshire in 1836, Crystal Palace at London in 1850, both designed by Paxton, and the Palm house at Botanical Garden, Kew in 1845, designed by Burton and Turner, the dream of a transparent roof was realized. Transparent roofs are now made of acrylics and other plastics for solarium, green houses, passive solar heating systems, etc. Kenzo Tange designed the Japan Olympic stadium roof as a catenary – flexible structure. French museum Louvre at Paris has an extension wing with a glass pyramid.

A catenary roof structure Interior of Yoyogi Gymnasium Japan Olympic by Kenzo Tange

A catenary roof structure Exterior of Yoyogi Gymnasium Japan Olympic by Kenzo Tange





Post -by Gautam Shah

Environment is a complex system. Its various aspects affect us differently. Some effects are concurrent and few are directional. Environmental barriers serving many different purposes are required.

Noise barrier Geluidscherm_OverschieWIND BARRICADES

Wind barricades are used for heavy wind sections as well as for the storm prone locations, such as sea fronts, valleys etc. These are designed to deflect the direction and diffuse the velocity of the winds. The barricades primarily depend on the quality of the terrain and man-made formations, such as sand dues, walls, screens, vegetation, walls etc. Projections like galleries, Chhajjas, screens, are also used for diverting the winds to the buildings. The flow is also diverted to specific interior areas of rooms by wind catcher ducts. Tropical houses have terrace parapets with a grill or lattice design to let the air pass through. Louvered doors and windows also control the air movement. 


Water barricades are required against sea tides and ebbs, tsunamis, flooding, land washouts, snow and rain storms and eddy currents. These are in the form of vegetation, walls, dumps of modular or irregularly shaped cast units, landscaping and terrain contouring. Holland has devised variety of technological means against ingress of sea waters.

Sea front barricades of Concrete blocks against land erosion


Sun shading barricades are shading devices, usually vertical or horizontal, and often in inclined positions. Locations above 23° N or South of the equator receive no sun rays from respectively North and South faces. All location under (within) 23° N or S of equator, however, receive some sun rays, and to curtail it sun shading devices of horizontal flat or inclined shape are required. For the same locations, on East and West faces, early part of morning and later part of the afternoons receive horizontal rays, but with Southern inclination. These require a dual shading consisting of horizontal and vertical (on the South side of the opening) elements. Sun shading devices such as Brise de soleil are used.

Solar baffles


Radiation barricades are used against radiation sources, such as furnaces, open fires, oil wells and oil storage tank yards. Such barricades could be natural or man made. Natural radiation barricades are in the form of hills, contours, dunes, slopes, trees, hedges, foliage, plants, grass, climbers etc. Man-made radiation barricades are protection walls, embankments, ramparts, retaining walls and dykes.

Jet Blast Barricade


These are created against super highways, railway tracks, airport runways, open mines, stone crushing plants and sites with pile drivers. The noise control barricades are made of dense vegetation, fibre boxes (grass), and hollowed or staggered construction. Stage podiums have parabolic overhangs to direct sound away from the stage and thus avoid the feedback in sound amplification system. Telephone booths in public spaces like malls, road sides, railway stations have specifically designed envelopes to prevent the background noise. Cinema and performance auditoriums are designed with optimum 1/4 to 1/3 audience occupation, as the bodies of audiences and their clothing absorb sound. Noise control barricades are in form of contoured planes to deflect and amplify the sound, low density surfaces treatments, baffles or cavities to absorb select frequencies of sound, or frequency generators to produce sound attenuation.





Post  -by Gautam Shah



Colours -Biennale Venezia > Flickr Image by Strolic Furlan -Davide Gabino

Dyes and pigments are colourants. These substances impart a colour to a material. Pigments are nearly insoluble materials, resulting in a suspension, whereas the Dyes dissolve during application, losing their particulate structure, resulting in a solution. Often a pigment is made by attaching a dye molecule to an insoluble particle. The difference between the two, can be said due to the physical characteristics rather than chemical composition.


Sun looking back at Trau > ART by Tivadar Kosztka Csontvary (1853-1919)

Dye molecules are comparatively smaller, so if each is presumed to be of pinhead size, relative size of a pigment particle would be of a football.


Traditionally pigments are considered to be more light-fast than dyes. Light destroys coloured objects by breaking open electronic bonding within the colourant molecule. Light fastness or permanence and stability are desirable properties of colourants. Lower Dyes are very much vulnerable. Pigments that are not permanent are called fugitive, as they over-time fade out.


Natural dyes for Alpaca Yarn, Peru, > Flickr image by Ken Bosma

Pigments change the colour of reflected or transmitted lights as a result of wavelength-selective absorption, wavelengths or parts of the spectrum are reflected or scattered. Pure pigments allow very little white light to escape, producing a highly saturated colour. However, a dye can only absorb light, and not reflect or scatter it. Pigments, can only subtract wavelengths from the source light, never add new ones, unlike the fluorescent or phosphorescent substances.


Organic pigments have carbon compounds. Natural ones were of animal and vegetable origins. Synthetic organic pigments include, alizarin, azo-pigments (yellow, orange red), phthalocyanine (variants of blue, green colour) and quinacridone (red-violet).

Inorganic pigments (of mineral origins) are metal compounds compared to organic pigments. Examples of Natural inorganic pigments: Oxides, umbers, ochres and siennas. Pigments produced synthetically often have the same names. Other Synthetic inorganic pigments include, cadmium yellow/orange/red, cobalt blue and titanium white.


Coatings are clear, dyed or pigmented. Clear-coatings are essentially, transparent to translucent in effect. Though, ‘water-white Clear Coatings are without any type of colourants. However, some tinted clear coatings or stainers include soluble colourants or dyes and often very minute quantity of non-soluble colourants or pigments. Dyes, are colourants soluble in water, organic solvents or oils. Clear coatings are used for where a very high level of transparency is required such as for the production of coloured metal foils and films, internal protective layer for cold-drink tins, coatings over paper, for flamboyant finishes in the paint industry and for wood stains (for floorboards and furniture). Dyes are also used for imparting colour to thermoplastics.


Tinted Glass > Pixabay Image by mploscar

Pigmented coatings are mainly opaque. The opacity of the film, in a few cases, is inherent in the molecular lattice of the film forming medium, but mostly is imparted by additives (pigments and extenders) of crystalline nature. Pigments, natural or synthetics have a fine particulate matter, but these are in agglomerated state and require dispersion. Pigments are ground using ball-mill, roll-mill and attritor like equipments. Dispersion increases the spread of pigment or its covering or colouring capacity. Hiding capacity of pigment also depends on the particle size, shape and distribution, concentration, and also on the film thickness and clarity of the film forming substance. Pigments due to their particle size, shape and structure have greater capacity to reflect, refract and diffract the incident light, compared to extenders on volume basis.

Colour for Coatings

Additives with optical properties form the major and the quantitatively substantial part of a coating system, which otherwise consists of liquids or liquefiable film forming substances. Extenders, are low refractivity materials. Extenders have refractive index equal or lower than the pigments. Extenders provide bulk to the film, condition the viscosity, help even distribution of pigments, improve the brush-ability and define the gloss level and texture.

Pigment grinding machine

Extenders are mostly inorganic compounds like oxides, hydroxides, carbonates, silicates and sulphate, of metals like barium, calcium, aluminium and magnesium. Commercial extenders are asbestine, barytes, blanc fixe, china clay, diatomaceous silica, dolomite, mica, precipitated calcium carbonate, talc and whiting or chalks. Pigment and extender particles, both are held together by strong forces of attraction and are often enveloped by air moisture and other affinitive substances.

INDIA – Holi Festival of colours Radha playing with colours Painting of C-1788





Egyptian make-believe Door width for one soul only


SIZE: Doors are primarily designed for humans, sometimes exclusively for passage of goods and animals, but more often sized for all purposes. The size of a door is in relation to: the proportion of the inside room space, fore-space, architectural schema, etc. besides the functional needs of transit, transport, exchanges of environmental elements (breeze, heat, energy etc.) vision across (framing), sound leakage and ingress, illumination, participation, privacy, etc.


The economics and the technology are two main conditioners for the size of a door, though not restrictive factors. Doors of extra ordinarily large sizes or monumental proportions have been used through ages. A large door denotes unrestricted transit or reception, fearlessness or power, affluence, and dominance.


The size of a door is also referential, and so contextual structures are conceived to enhance the perceived size of a door. Doors of smaller sizes than nominally necessary, are used to slow down and thereby control and check the chaotic traffic of entrants. Doors are intentionally made smaller, if these are insignificant, or need to be concealed, such as the secret or escape doors. Smaller doors are stronger, but not necessarily easier to open or shut. Smaller width openings increase the integrity of the load-bearing structure.


The size of a door is also governed by the architectural scheme of the built mass and its relation with the surroundings. Fort gates and other gateways have not only large doors but also have elaborate structures like abutments, ramparts, bulwarks, bastions, bastilles, battlements, belvederes (Chhatri), buttress, campaniles (bell towers). These appended structures increase the significance of the opening.

Gwalior, India Fort Gate , Architectural elements make the opening more significant

Gwalior, India Fort Gate , Architectural elements make the opening more significant


Historically, very wide doors have been a necessity, for functional passage as well as for splendour. Wide door or gate openings are provided for ceremonies, processions, etc. Wide doors, however, are incapable of regulating the traffic. Such openings need either barricades to channelize the traffic, or multiple narrower door systems.


San Pietro Vatican -very large door

Tall doors were less of the functional requirements, but a compulsion in monumental structures, with royal or public patronage. For very tall doors, the construction of strong shutter and relevant opening control mechanism have been the greatest deterrent. Tall opening like effects are created with architectural door portals, where the functional door is very much smaller.

Bulund Darwaza, Fatehpur Sikri India -Very large gate structure but functional door smaller

Large doors require lateral stiffening, as the usual thin shutter leaf construction is insufficient against buckling forces such as the wind, blasts, and often sonic boom pressures. Aircraft hangers’ and spaceships’ assembly workshops (Apollo, Columbia, USA) have very large doors with additional lateral framing. Similarly dams and canal gates have to resist not only the pressure of retained water but dynamic pressures of waves and eddy currents. Such doors are designed as a 3D entities. Stadia and such public spaces where people are likely to push the gates, extra lateral stability is required.

Sea gate with 3D structural framing -Model

 Traditionally doors have had a vertical form. The vertical rectangular form makes the opening taller then its width. It reduces the load on the hanging devices such as hinge or pivot, and so easy to open. The smaller width doors are technologically more efficient to construct and operate. Doors with two shutters divide the door further, and create a narrower version.

The width of a door is decided primarily on functional passage needs, but any heights above human head level (or with the head loads) are extravagance. Width of a door determines the density of traffic and the size of articles that can pass through it. Industrial doors are conceived for passage of goods and lifting mechanisms. Sliding doors have easier handling if are wider then their heights.

Aircraft Hanger gate

Proportions of doors relate to the architectural design. Most common set of proportions (Width: Height) have been: Two squares 1: 2, or Golden proportion 1:1.61. Height of a door is determined by the architectural requirements, but width of a door is in proportion to its height.


Some famous doors’ proportions are: Treasury of Atreus, Mycenae 9′-0” x 18′-0″, Parthenon, Rome 0′-0″ x 24′-2″, Erechtheion, Athens 8′-0″ x 17′-2″, S. Martin, Worms 5′-8″ x 11′-3″, Palazzo Pietro Massimi, Rome, main entrance door 6′-10″ x 13′-8″.


 WIDTH parameters

Actual width or width of passage is less for door openings set with architectural door surrounds, compared to wood framed and hinged doors. Pivots other than at the extreme corner of a shutter restrict the nett opening available.


In modern times, as a social concern, it is essential to provide doors widths suitable for disabled persons, such as using walking sticks, crutch, a walker, a wheel chair, stretcher or assisted by others. Width of a door for, toilets, elevators, closets, store rooms, change rooms, and such other lone user utilities are considered very critical for ergonomic profiles of such users.


Simple sliding doors allow very exact control over the width of opening. Automatic sliding doors such as for elevators and for entrances of public buildings automatically open to width governed by the density and frequency of traffic. Revolving doors have optimum opening size to maintain the air lock and prevent anyone forcing a reverse movement. Folding shutter doors allow incremental width of the opening. Garage doors sliding up were designed to get a maximum unhindered width of opening.

Subway Multiple Doors -discipline the traffic

HEIGHT parameters

Height of a door is designed with three parameters: 1. the height available within the opening, 2. the height of the door head, and 3. the height of the threshold. The actual passage height of a door is acutely affected by the level of terrain immediately inside and outside the door. Low level doors have been used to reduce the heat gain or loss (e.g. igloos), the storm water entry (e.g. sea front warehouses in America).


A threshold protects the interior from dust, rain or snow storms, however, a taller threshold reduces the door passage height. A high threshold makes a door little less functional for entry-exit, and takes it closer to the identity of a window. French windows are only high threshold doors.


Egyptian temples had very tall openings, the lower section was shuttered and the upper section was a gap. Gothic churches had upper section of the door converted into a rose window. Very tall doors, unless required for passages are turned into transom lites. Very tall doors require a visual correction. Romans constructed tall doors with a wider base and narrower top.


These are dimensions, recommended for Human passage through a Door. The size in brackets show adjusted sizes as per ISO modulation system of @100x mm.

1 Height of Indian Male without head load or raised hand 

            @ 95 percentile 1751 mm (1800mm optimum)

2 Height of Indian Female without head load or raised hand

@ 95 percentile 1615 mm (1700mm optimum)

3 Height of common Indian (M+F combined factor)

@ 95 percentile 1741 mm (1800mm optimum)

4 Erect stature of common Indian (M+F)

@ 95 percentile 1771 mm (1800mm optimum)

5 Raised hand of common Indian (M+F)

@ 95 percentile 2289 mm (2300mm optimum)

6 Width of Indian Male

@ 95 percentile 619 mm (700mm optimum)

7 Width of Indian Female  

@ 95 percentile 599 mm (600-700 mm optimum)

8 Width of common Indian (M+F combined factor)

@ 95 percentile 619 mm (700mm optimum)

9 Sideways width of Indian Male

@ 95 percentile 409 mm (500mm optimum)

10 Sideways width of Indian Female

@ 95 percentile 439 mm (500mm optimum)

11 Sideways width of common Indian (M+F combined factor)

@ 95 percentile 419 mm (500mm optimum).



Post by Gautam Shah

A door is a prime target for an intruder for two reasons: a door is the entrance to a building, so a break-in here equals, to capturing the building. The door (entrance, back or any other exterior) is a node where other interior openings (of rooms, stairs etc.) verge, and for the intruder it becomes easier to spread out from here. However, buildings have many other ‘softer’ points for easier intrusion, like windows, thin walls, weak roofing, etc.

Ruin Dilapidated Building Decay Lapsed Old Home

Door security also relates to integrity of the door against high speed winds, rain storms, birds and insects, etc. Security also relates, to forcing an entry to save lives. A very strong door that is virtually unbreakable or impenetrable can pose equally a major problem in case of a disaster. Similarly a toughened glass door is difficult to break out or in during fire or accident.


There is a tendency to caution the users for the security risks and hazards a door system could have, through signs, signage and other forms of alarm systems. But it is always ‘better to reduce the risks, do away with the hazards through design than warnings’.


The strength of a door system derives from: its location, size, composition, materials of construction, the support framing and the nature of basic hardware and additional safety appendages.

Doors Street Old Brazil Center Santos

Security perception of a door varies from one situation to another. A door visible from a street, such as set flush with the wall surface is less a security risk than the one set back in a niche. Doors supported on all sides such as the hatch doors are stronger then supported on one or two sides like the sliding doors. Doors opening both ways are stopped by the hardware and are poorly secured such as the pivoted doors. A door of ordinary glass if breakable is a security risk, but being a see-through element in a well-illuminated environment may forestall break-ins. An intruder prejudges the entry but also remains fearful that someone can see from the outside. Malls, stores have glass doors to make the interiors visible and so safe. Fewer doors make a building safer, but adequate emergency exits must be provided.


Door security is now considered in more in holistic terms. A well planned and managed community provides better security then the lonely but strongest door system. Electronic and other surveillance systems can eliminate the need for heavy doors.

Community Security

Gated Communities have common security systems 


Community surveillance systems: Where a community or a building is safe, its sub units (offices, residences, etc.) may not require strong individual security arrangements. Community security system consists of organizing units of a building and sub units within each zone as a domain or bastion with single entry. Several buildings within a community form a precinct, though not bounded by walls but one that can be patrolled circumferentially. Many colonies discourage erection of high and opaque compound walls or hedges, so that individual units remain visible by other members. Yet in case of a complete blackout or during riots some form of security surveillance is necessary.

Community Surveillance

Integrated security surveillance systems solve many of the individual security issues. It works on observation of oddities, recording it for post analysis, warnings, activating the multiple precautionary measures (cutting of exists, power cuts, sprinklers, etc.) Such security systems are part of both the door and the opening system, or even spread across a building. An integrated security system is not an appended system but rather designed and compounded with the building’s structure and functions as a unified method of building management. The system to be successful requires coordinated working of many different agencies. An individual user cannot hope to install and operate such a system, but must contract out such a service.




Sistine Chapel ceiling with Art-work by Michel Angelo between 1508 and 1512

A ceiling is a finish system applied over the inner or the bottom side of a roof or floor, compared with a flooring system which is applied to the outer or top side of a floor or roof. It is considered the upper limit of a room space.

Embossed Brass sheet ceiling units

Ceilings function as a ‘touching’ system, by being very close to the under side of a floor or roof system, or as a suspended system, little away from the floor or roof. Ceilings as a Touching system provide a cover, following the under side contour of a floor or roof. Whereas, suspended ceilings are designed to modulate the height values of space below and to cover space for various services.


Touching ceilings


Touching ceilings have no hanging or suspending members, so are more stable. Where small length hangers are required to accommodate conduits, wires etc., are of stiff materials only. Touching ceilings are made of preformed boards, wood planks, wood composite sheets, metal sheet forms, laminated paper composites, etc. fixed to a mono or bidirectional frame work of wood, sheet metal or rolled sections. The sections in turn may be hung through stiff hang fasteners from the roof structure such as joist soffit, beam or slab bottom. Touching ceilings are also like roof underside cladding or plaster. The cladding pieces are cut to accommodate the single, double or irregular curvature or slight variation in joints width. Plastered ceilings are deposits sprayed or trowel finished with suspended solids or foamed materials. The surface may be rendered for texturing or press hollowed for visual as well as acoustic needs.


Suspended ceilings


Suspended ceilings leave a back-space of various depths. The spaces are left to accommodate pipes and ducts and to enforce a desired finished surface curvature. Such ceilings to modulate the space below often leave substantial ‘dead’ space above. Ceiling materials with high stiffness such as wood planks, glass, require equally rigid structure. Ceilings made from modulated pieces (panels, stripes), stretchable materials and thin materials can accommodate stresses and may not require rigid fixing. However ceilings subjected to upward and downward stresses as a result of increase and decrease in interior air pressures (such as auditoria), require both, compressive as well as tensile hangers.

Commercial acoustic boards ceiling


Greeks used ceilings primarily to cover the roofing elements like, beams, joists, rafters and truss. The ceilings had coffered configurations. Romans created concrete vaults with coffers to reduce the weight. The Pantheon five rows of coffers in the dome and each coffer had receding flutes at the edge. In Gothic cathedrals under side of galleries, triforium etc. had flat ceilings. English medieval period the ceiling’s shape originated from the vaulting flutes terminating into complex circular patterns. Ceilings became extremely articulated in Renaissance period. Non secular buildings had ceilings in all rooms with guild work.


A tall ceiling with planes meeting at an angle, similar to a church is called a cathedral ceiling. A vaulted ceiling follows the vault geometry but accentuates it with many such repeated shapes. A concave or barrel-shaped ceiling is curved or rounded upward. A coffered ceiling is has recessed square or octagonal panels. A dropped ceiling is a touching ceiling. A cove ceiling uses a curved plaster transition between wall and ceiling, to create one continuous surface.


Ceiling Patterns


Ceilings are patterned for two distinct reasons: 1 to impose a design discipline, and, 2 to impose a texture. Patterns emerge from the natural grains (colour, variation, orientation) of the material, lay out of structural or natural joints, regimen forced by the sub structures, fasteners (screws, rivets), junctions of geometric and other shapes, etc. Patterns are created for providing texture to the surface of the ceiling. Textures either help highlight or subdue the joints, grains and shapes present in the ceiling. Textures accentuate or de-emphasize the light reflection, gloss etc. Textures, perforations and cavities enhance the sound absorption.

Rose Wood Ceiling Rameswaram Temple S India



Folding Ruler

Measures are the basis of all exchanges and for checking the efficiencies. Measures identify the quantum of work and the productivity in time scale. Measures are based on body sizes or capacities, but these have many racial and regional variations. It is possible to equate out such differences in a personal exchange or barter trade between neighbours. But, the same proves to be very difficult for trade with far-off regions. Intermediary like, brokers, caravan masters and shippers facilitated trade with other regions and also made large profits through Conversion of measures. Some form of common measure system is required to communicate the achievements of human endeavours.

The inconsistencies of the measure conversions are solved partly, when monetary pricing replaced the bartered trading. Monetary valuation provides a common ground for comparison. World wide, the trading blocks had to concur to a common set of Nominal measurements.

All measure systems such as weights, lengths, volumes were once mutually incompatible, as each had a different scale of sub fractioning. The problems multiplied when measures were equated with equally varied units and sub fractions of monetary units. This was sought to be solved during the French Revolution.