MAINTENANCE versus REPAIRS of Buildings

MAINTENANCE versus REPAIRS of Buildings

Post 363 ⇒   by Gautam Shah 


To maintain a building means, in literal sense is, `to preserve from loss or deterioration‘. Maintenance is the act of maintaining, supporting, preserving, continuing, and defending. A Repair means, to mend, to restore, to revitalize, restoration after injury or decay, reinstatement of loss. Maintenance is preventive in nature, compared to Repair which is a corrective action.

Well -Baoli Ghaus Ali Shah, Farrukhnagar

Buildings with adequate or timely maintenance require lesser repairs in extent and frequency. Unrepaired buildings decrease the efficiency of maintenance. Maintenance is not designed to change the building.

B.S.3811 (1964) defines maintenance as: ‘A combination of any actions carried out to retain an item in, or restore it to an acceptable condition’.

To retain

–preventive maintenance

To restore

–corrective maintenance

Acceptable condition

–to the person paying for the world

–to the person receiving the benefit

–to someone outside enforcing minimum standards

–to society in general.

Mud plaster requires frequent maintenance

Maintenance techniques are employed for two ends: Improvement: superior to the original design standards, and Restoration: equal to the original design standards. Where the design requirements are stated in the form of parameters or specifications of performance, these could be used for establishing the maintenance standards. Performance requirements need to be incorporated in the maintenance manual concurrently with other explanatory details about the building and its services.

Taj-ul-Masjid Gates Bhopal Madhya Pradesh India

Planned maintenance is an organized effort carried out with forethought, and control. It is to be conducted regularly but must accompany all major changes in the building. As a forethought out action it is apparently well documented.

Preventive maintenance is carried out at predetermined intervals of time or use cycles. It is also initiated by professionals, as soon as minor decadence is noticed.

Minor repairs with regular maintenance

Running maintenance occur on regular or continuing basis, in the form of running a plant, or as a service for a running system. These take the form of nominal activities like cleaning, waste disposal, oiling, fuelling, cooling, warming, etc.

Thatched roof maintenance

Buildings, consist of both, physical and metaphysical things. Maintenance means continuing the physical entities, by removing decay causing elements including replacing the warned parts and components. Metaphysical things like image, tradition, fashion, etc. are maintained by adopting incorporeal or pseudo means. In a building, the maintenance strategies of realist and absurdist nature operate concurrently.

Elgin Cathedral choir wall -need for repairs, maintenance and conservation

Actuators for maintenance are both, internal and external to the building. Externally the climate has the greatest effect, though varying in severity according to the orientation and location of the building. Internally the user and activities affect the building. The actuators of these effects are also mutually dependent. Changing life styles, living standards and economics affect the nature of maintenance. Buildings where quality of space determines the efficiency of work activities, and which in turn scales the economic returns, are well maintained.


ROOFS 3 -Skyline and Silhouette

Post 328 – by Gautam Shah



Roofs are most articulated elements of a building. Roofs form the skyline of a building, visible from a distance as a silhouette during twilight hours. A roof distinguishes a building among many other roofs. Roofs are single entity form covering nearly whole of structure, like for a pyramid or Pantheon. A roof could have a single domineering form, by height, mass or surface treatment. The roof mass is bloated by adding translucent forms like a belvedere, Chhatri, Turrets, galleries, Cupola, etc. These forms of varied sizes and shapes create an undulated edge over the roof.




Roofs have been important as they form a resonant skyline. Historical buildings formed a vibrant horizon by being on important terrain, large scale, height and the form. There are very few examples where a single roof structure (Parthenon) was created for dominance. Otherwise, several buildings forming a complex or an estate composed a variegated skyline. Such outlines were not pre-planned but evolved through deliberate additions and alterations over a period of time. In many cases the deliberations preceded with case study through on site sketches and scaled models.

The scenario has changed during the last century due to aircraft and satellites. Both have provided means of observing buildings from higher elevations. This has been a key factor in shape forming of not only high rise buildings but also large footprint structures. The composition of roofs (and entire structure) in making the skyline and silhouette, is pre-visualized for different atmospheric conditions, planned illuminations, and viewing positions including ground and air.


These add-on architectural elements are rarely functional entities, or are connected with the main Interior spatial character of the building. There is an attempt to articulate their scale, sequencing, proportioning, scaling, etc. Well-designed buildings executed in one era usually have such well integrated roof elements. The integration is seen in ‘picturesque’ views from all sides and corners.


Roofs that are well integrated with the architectural layout of the building have a mutual affinity. One of the first such building is Hagia Sophia of Istanbul. It was the extra ordinary scale that perhaps did not allow any room for manipulation or decorative improvisations. Whatever one, perceives from outside, is the exact reflection of the interior space arrangement.

Istanbul_Hagia_Sophia_SultanahmedA similar roof related truthfulness is seen in many of the Gothic structures of an earlier era. In later periods the roofs have been loaded with many decorative elements, statuettes, etc. All Gothic roof structures rise up from their vertical elements, in one continuum.



Roofs, have been axially-balanced compositions, and also disarrayed mass arrangements. In case of religious buildings where the attention is focused, the building and its roof follow the same system. The composition could be single, multi-axial or cross axial, yet a balance roof emerges. This is also true of Government buildings, courts and other public buildings.



Roofs of single form covering the entire building have been used as the structure to seen and recognized from a distance or sky. Airports, Railway stations, Stadiums, etc. have single roof mounts. Space station workshops, aircraft hangers, large industrial plants have large functional space, enforcing single roof structures.


Palaces and temples have very large vertical surface extent, and as a result the need for a bloated roof entity is not very strong. The roof lines are though undulated in various configurations. These structures have mixed roof structures, though well arranged but not in any formal or axial manner.




Roofs, in many buildings are, sloped structures. Sloped roof stretch the vertical face it abuts. This characteristic has been used in many buildings. Roofs have frontal slopes or side slopes accompanied by triangular pediment on main face.


Modern buildings have roofs that acutely technical facilities. Few buildings have roof top public-use facilities like a view deck. But buildings’ skylines are designed to form a distinguishing entity in a mass of urban developments. Buildings are conceived to be visible and recognizable identity, in all types of weather and lighting conditions.





Post 311 – by Gautam Shah 


colour in architecture 1

Colours of Buildings affect many spatial qualities of a built space on both, the interior and exterior faces. Colours used in buildings once were mostly of the natural material surfaces or as applied on it. On exterior face the colour distinguishes a building among many other nearly similar ones. It also emphasizes the architectural elements. In early ages of a street without intensive night lighting, the colour of the building allowed it to be perceptible. Sides of the openings with lighter tones helped the night interior light to have a wider glow. The choices for exterior colours were fewer then on the interior sides. Colours of the naturally available materials were smartly exploited in several buildings across ages and locations. Natural materials like timbers, stones, soils, or materials processed out of these from the local region have phylogenetic relationship. There is an equality of hue and tone across the local materials.



The colour palette began to change with trade across distanced places. The adventitious effect began to occur when minute quantities of materials such as minerals, pigments, and dyes were bought from other regions. The first use of these additives was in the form of painting or colouring of leather, cloth, timbers, art work, ceramics, fabrics and body make-up. The colour schemes of ceramics, paints and fabrics were drastically altered. These colour-effected materials were initially used in palaces or religious buildings. The effects, however, percolated to ordinary buildings and people in different way. Here art and craft objects of exotic colour schemes were used as a rarity and as gesture of modernity.



Knossos Porch ch Exterior colours

Exterior sides of buildings for a very long time (as much as 9th C.) had colours of the natural materials. The surface variation was through the inclusion of architectonic elements, textures and joints’ patterns. Greeks used streaks in natural materials, mosaics and joint’s pattern for surface variations. The Ordinary Romans exploited debris of old buildings for variegated marbles. These colourful marbles were not local as came from distant lands. The Romans, on the exterior surfaces also used calcimine type of water-based coatings with iron oxides as the colourants. Romans created borders and central patterns with mosaics and inlay pieces of colourful stones and glazed ceramics. Byzantinian used marbles from debris of buildings but their intention was contrast and pattern definition, rather than a unified colour scheme.

colour in architecture 2




Interior spaces once had dominantly natural colours of wood, plasters, terracotta, marble, granite and other building stones (like slate, sandstone, quartzite, etc.). These colours were enhanced or supplemented by embellishments made of metal and furnishing fabrics. The interior spaces were stucco or fresco painted. The walls and ceilings had decorations of paintings, murals, carvings, and colourings. The colours of embellishments and decorations though substantially of natural range were much intense tone and purer hues. Interior spaces were protected spaces so lot of non-sun-fast colours and bleeding coatings (water soluble) of natural gums could be used. Ceramics were the next lot of exotic colour materials.

colour in architecture 3

Colours in Egyptian Dendera Temple

In early ages metals like bronze, brass, copper, iron, tin, gold and silver had natural colours. It was not possible to re-colour these substances, except the patina formation on bronze was a controlled process. Metals were ‘colour’ altered by processes such as metallizing, chasing, inlaying. Tin, gold, and silver plating was effective way adding a ‘coloured’ identity. Metal’s own colours or altered with plating were very distinct from the ‘earth’ colours of minerals, glowing hues of dyes or ‘fired’ colours of ceramics. The metal colours were soon challenged by glass. Glass with its impurities had many different ‘Metallic’ shiny colours. These were now pot coloured or stained. The Metals and Glass were successfully coloured in multiple hues at the start of middle ages.

metal-glass facades

FLOORING COLOUR (earlier Blog article)

PATTERNS in FLOORINGS (earlier Blog article)



Post 309 –by Gautam Shah





First ever human endeavours of unprecedented size and complexity, such as construction of buildings, forts, cities, or palaces, civic facilities like aqueducts, bridges, gates, fighting wars and calamities, writing epics, creating works of art, all have been executed as projects. These projects require strategic planning, research, innovations, procuring and transporting the supplies, storage, human resources, tools and equipment’s deployment. Such projects often lasted for several generations, or were conducted by different people taking over the controls. The three important elements of conducting a project are, namely: Documentation, supervision and feedback system helped the ‘timeless’ continuity by managing the changed circumstances.

Hanging Gardens of Babylon



Historically large projects were initiated by the powerful coterie of rulers who could command large number of workers as believers or slaves. The armed forces were the most organised of groups, and were preferred executioners. Post 14th C Europe and India saw rise of business men, who patronized construction of large projects like palaces, temples, cathedrals. Early 19th C. saw emergence of different class of entrepreneurs who began to build very large Industrial units, warehouses, wharf and rail roads. These industrial age projects, in comparison to any other project in the history, were conceived, executed and made operational in a very compact time frame. The time compression necessitated new methods of project management. The building had to be an economic entity. The style was not shackled by architectural isms, materials or technology. The new breed of industrial project initiators, were joined by new Governments that were turning more democratic. The Government sponsored economic activities were constructions of bus and railway depots, ports, canals, dams, bridges and roads, etc. These Government projects were often designed executed and managed by private agencies.

Industrial plant

Panama Canal under construction 1907

Mexico Cathedral

Earlier Designers were Planners of the project, and to many extent were active participants in execution process. These allowed them to detail and improvise the project during the execution. But during Industrial evolution Projects were planned for production strategies, then designed (Buildings) and executed by different agencies, and ultimately made operational. These processes required new methods of project handling or management.

Ship Yard

Just before and during the world war II, it was necessary to ensure that production of war materials of all forms matched the anticipated demand, and was supplied to the right place at the right time. For this purpose new planning and forecasting methods were required. After the world war, these mathematics based planning methods developed into a new discipline known as OR -Operations Research. OR is a discipline concerned with the planning, assessment and control of operating systems, such as industrial production, commerce, etc. or virtually any human effort. Interest in the methods for design and logic of these systems, rather than in their operations, led to another subject, SE -Systems Engineering.

Decision making in design is covered by SE. Decision making in planning of the construction, execution, implementation, operations and the management thereof, is covered by OR. In reality these two disciplines overlap and merge into an overall systematic approach for Project Management.

As a discipline, Project Management has developed from several different fields such as building construction, mechanical engineering, military projects, etc. Two types of mathematical project scheduling models were developed.

Miami station

The PERT -Programme Evaluation and Review Technique was developed as part of the United States Navy’s (with Lockheed Corporation) for Polaris missile submarine programme, and the CPM -Critical Path Method was developed (jointly by DuPont Corporation and Remington Rand Corporation) for managing plant maintenance projects. Other such tools were like: work breakdown structure (WBS) and resource allocation methods.

By the 20th C. project managers began to (time) schedule productions for the rapidly changing markets (choices, technologies). In the 1950s and 1960s project planning methods for time management and cost control through inventory, warehousing, transportation management, were developed. Much of this development was based on the concept of determining a precedence relationship (that is, identifying which work activities must be completed before other work activities).

Gas-Oil Platform Bombay high seas

Business was facing challenges of more complex products and services, demands for better quality products, cost-conscious customers, faster development cycles, stiffer international competition. There was need for joint ventures to share risk and collaboration for leveraging the expertise. Project management was designed to help the business leaders do just that.

.Soyuz Space craft

Enormous projects are often called programmes, divisible into multiple projects. The projects, in turn, can be broken down into smaller sets of activities. These are further dissected into tasks, or work packages. Tasks are assignments for a person, equipment or a facility (department). Project management techniques are applied to planning and managing activities at all such levels.



Post 295 – by Gautam Shah


Valuation of buildings is done on many different counts. A building stands on a land. So the absolute value of a building consists of Land and the Structure. A land nominally has a Foot-Print, an area measure in parallel to the gravity plane. As city administration assigns a Building Capacity in proportion to not only footprint area, but for submerged, eroded, or cut-offs for used in public utilities.


The ownership of land, in a modern day urban area is conditioned by several conditions. Footprint areas could be several time less (or in a rare case, more) then an area recorded in historic Land documents. Similarly the capacity to build on it does not depend on a real footprint (Satellite picture or surveyed plan), but several administrative conditions.

City Facade Architecture Europe Frame Renovation

Valuation of Land is dependent primarily on How much, one can build on it, and for What purpose one can develop it (commercial, residential, industrial, services, etc.) It is, however, more dependent on the nature and tenure of ownership of the land. A land may be fully owned (as described in tradition land purchase documents –ownership entitlement from bottom of earth to the topmast part of sky). The tenure may be permanent (as described in tradition land purchase documents, –Tenure to last as long as sun, moon and stars remain). The land ownership may be a leased entity for a short (19-99 years) or very long term (999 years) basis. Short term lease often expires before a building perishes.


The most complicated ownership entitlement is where the Land is owned in terms of capacity to build (FSI) on it. An FSI or Floor Space Index is an assignment of specific proportion of building capacity. The FSI remotely relates to the Land Foot print, but does not represent the reality. It is made more complicated when existing owners-occupiers of the land sell the right to build further over an existing structure, or in the residual parcel of open land.


Land has a contextual value depending on its location and surroundings. The location related value may go up or down due to many extraneous circumstantial reasons. Urban lands have a value in capacity to get the possession of the land by financial enticement, alternative arrangement, force or legal means.

A Structure on land has three sets of values, ONE -relates to its utilitarian purpose (nearly matching the original concept), TWO -concerns with remaining life as a sheer built form or shell (presumably utilisable for some other occupational use -different from the original intention -salvage value), and THREE -bears on its debris value. A comprehensive judgement of all three aspects is made to define the value of a building.



In another valuation system, a land or building, or both together, are considered an asset with an absolute value. The asset value can be exploited to yield a rent. From the Rent, expenses for regular inputs, periodic repairs, and maintenance, etc., are deducted. The monetary surplus is considered an income (or loss), if its rate of return is higher when compared to an investment in other fields (equal to the absolute value).

Land + Building, are assets (real or possible), and the Valuation is carried out to assess the income potential, actual profit or loss. Valuations are carried out on year to year or occasion to occasion basis, to ascertain addition or deduction in the value. Such assessments help in computation of wealth, and other taxes, and for calculating depreciation, insurance premiums, etc.


WALLS and Buildings

Post 244 – by Gautam Shah


A wall is a planner structure, generally vertical, with a proportionately narrow thickness in comparison to its height and length. It is a barrier system, like fences, barricades, partitions, etc, and used for dividing or enclosing a space. Its most distinguishing function has to bear the load. It bears its own weight -the self load, and also other imposed loads of the super structures or sideways thrusts. Walls ultimately transfer all the loads, own and imposed loads or thrusts to the earth. One of the most efficient load transfer systems to the earth is in perpendicular direction to the gravity. As a result, in all structure compositions, the vertical walls predominate.

Walls of Stairs Kolkata India

Allen Lambert Galleria Toronto an atriumspace by Santiago Calatrava that connects several heritage buildings along the side of it Wikipedia Image by Secondarywaltz

Imposed loads on walls emanate from other structural systems of the buildings, such as floors and roofs, beams, services, etc. and from the occupancy of these systems, like ‘live’ loads of people, flora, fauna, goods, storage utilities. Thrusts from within the structures are transferred by the walls to other bearing elements, or resisted and converted into a gravity bearing vertical component. These loads include from arches, beams, vaults, etc. Thrusts also bear upon the wall due to the lateral resistance provided to other elements such as water, grains, sand, soil, etc. and retained liquids or gases. Walls also endure pressures arising due to dynamic movements of live loads and shifting dead loads, earthquakes, and energy vibrations of sound, wind, etc.

metal-glass facadesWalls carry distributed loads, but frequently loads concentrated at a point induce local stresses and failures. Walls also fail, under excessive distributed loads, at its weakest section, get crushed or deformed depending on its homogeneity. When a wall has width equal to or less than its length, it becomes a column, and loses its meaning. Moreover, a wall that has a height equal or less than its width, remains an in-fill course or a layer only. Walls without any external down bearing imposed loads are called partition walls.

Uppsala cathedral wall

A wall carrying only side-thrust is called a retaining wall. A wall which carries the load of upper structure and also retains earth is an abutment wall. A gravity wall resists the side thrust of retained material by its dead weight. Gravity walls primarily have a trapezoidal section, with wider part forming the base. Cantilever retaining walls have ‘L’ or inverted ‘T’ section. A buttressed wall has additional intermittent pieces of lateral walls on the open face, to strengthen the mass. A counter-fort wall has a similar system (often as a structure in tension) on the inside or the loading face.

Wall Hazara Rama temple Hampi, Karnataka India Wikipedia Image by Ms Sarah Welch

Tabo Gompa - old walls and chortens Wikipedia Image by John Hill

Retaining Walls

Walls as barriers resist variety of forces or energies. A translucent to opaque wall can reduce light transmission. A wall of an absorbent material and geometric configuration is used in attuning sounds. Latticed walls as barriers filter out select elements. Small height walls are used as compound or estate walls and as parapets. Dispersed vertical linear elements used as non-continuous barricade function like walls. Curtain walls are rigid membranes that envelopes a building to protect it from winds and rains and many instances bear the surface shears.

Wall of Porta San Giovanni Wikipedia image by

Edward Durell Stone US Embassy Delhi Latticed wall

Walls are ‘loaded’ along and across the width section, and sometimes along the length-section. To bear a load, a wall is expected to have adequate surface cross sectional area in a plane parallel to the gravity. These surface component are made of width and length of the wall. Theoretically, a wall can have an infinite length and single size module of width. Nominal walls however, are required to bear a variety of loads, thrusts and stresses. So walls need some sectional depth, depending on the integrity or homogeneity and strength of its materials, in addition to the geometric formation and composition. Height of a wall is a finite element, though theoretically a wall could be infinitely tall. A tall wall, proportionally, turns into a slender structural entity. Wind and other vibrations over the surface of a tall or slender wall are random (stochastic) motions. These cause dynamic effects in many different directions. So even if depth (thickness) of the wall due to high integrity of material, composition or geometry, can bear the loads, the transmission of loads to the ground is not harmonic or consistent.

Walls of Red Fort Delhi India

Walls of Hyderabad (Pakistan) Fort -Pacco Qillo Wikipedia Image by MUrad Ali Shah Bukerai

Very thin walls are used in shells, domes, tanks, plates and membrane structures such as balloons. These are often called shell or membrane structures depending on their structural transmission. These structures often have indistinguishable wall and roof elements. A shell structure is classed as compressive structure, whereas a membrane structure like a balloon is classified as tensile structure. Thin structures are used for their light weight and economy. Membranes are thin and pliable materials or formed by ‘bloating’ or stretching a material along its plane. Membranes ‘wall’ or surfaces can carry well-distributed loads, but are incapable of taking any pointed loads, unless material is tear or puncture resistant. Boat sails and circus tents are examples of membrane structures. When a hard, homogeneous and rigid material is used for creating a thin wall structure it is called a plate or shell structure.

Walls of wonky brick building crooked old masonry house

Walls of Cooling tower at Thermal poer station Neyveli, Tamil Nadua India Wikipedia Image by NLC India Ltd.

Sail Ship -a membrane wall

 Walls of space vehicles and stations in outer space have few superimposed loads on the walls (once far beyond the nominal gravitational zone) however, if gets converted into stresses. The stresses ultimately result into some form of kinetic energy disturbing the equilibrium of the craft or station. To maintain the equilibrium (position and location), occasionally course-correcting boosters are fired.

Coventry Cathedral Ruins Flickr ImageOpenings like doors and windows, and provisions like niches, alcoves, weaken a wall. For reasons of load-bearing capacity of a structure, openings at lower level must be fewer of smaller width. Lower sections of structures, however, have lesser solar exposure, so more openings are required. Openings are placed one above the other so as to leave uninterrupted vertical wall masses to transfer loads directly to the ground.



Post 179 ⇒   by Gautam Shah 

Buildings are invested with many different values. The values are, utilitarian aspects, sensuality, materials, technology, architectural character, spatial qualities, style, patterns, scale or proportions and antiquity. These values arise over a period of time, and what we perceive is a cumulative imprint of it. The values are subjective and circumstantial judgements and so are considered partial considerations. It is never possible to know how, why, and when the values were endowed.


Restored building Yatkha Bahal Nepal

It is not possible to restore a building to an ‘original condition, as none exists in a single time and space profile. It is also accepted that, a comprehensive restoration is never possible, because then one needs to consider all these values concurrently. Restoration, at best is a subjective approximation. Restoration inherently involves generalization, ignorance, insincerity, wrong decisions, lack of resources, and time constraints.

Restoration, is however, often considered easy, as the retained or restored identities provide a link to a perceived image of the past. Restoration is substantially an alteration, where nonconformist elements are changed. As a result in every restoration, something of the original character is irretrievably lost. ‘Too many restorations ultimately take away the original character of the building.’

Restored dockyard buildings to a different use at Alfred Road

Restoration to be purposeful must remain superfluous. Restorations at all times must remain irretrievable that is fully removable or demountable. Restorations without harming the substrate or basic fabric, preserves the essence of the building. It is ‘prudent to restore with a superfluous but traditional material, than employ an innovative but integrating material’. Integrated restorations affect the basic fabric or structure of the building.



Postby Gautam Shah




In our day to day life, we use many different types of objects. At a very simple level an object is made up of only one or few materials. Such objects though have variety of sizes and shapes, and serve similar purposes. Parts could be elemental units that form assemblies or composition but need not become functional components. Such efforts may however, lead to abstract systems, essentially revealing relationships.

Parts are always replaceable, and similar parts are affected similarly.Parts may not be similar but gain a value by being in certain position for required purpose.


When we recognize an object as a part, we know that a whole range of nearly similar objects, worthy of being a ‘part’, are available. A part has universal character, but when assembled into a component, it acquires a different personality, due to the placement, location and function. 640px-Bihar_bullock_cart_parts


A part is that elemental unit to which the whole can be reduced or resolved.

A screw, nails, handles, a razor blade, buttons, are examples of parts. These are destined to become members of a larger entity -the component. Cement, sand, water and bricks, as parts, form a masonry wall, which in turn is component of a building. Parts like a tube, tyres, air, rims, together create a component -the wheel. The wheel with many other components makes up a system of movement.

Within a composition, parts exhibit an active to passive interactions with other parts, as determined by the design. But parts dealing with the environment (including the user) often show indeterminable behaviour.




A component is unique composition of many parts, to serve a specific purpose, it must remain steadfast to a function and yet to be relevant. Components have a specific identity, compared to Parts, which have a universal character.


A component is more intimately linked to the larger composition-the system, than a part is. Components are conceived to be within a larger composition or system, and derive their identity on the nature of their role within the system.


Some components remain static and so are useful, but many others are dynamic and only for that reason, become members of the functional system. Components manifest at very specific location and occasion, so can be easily identified and separated. A part is also a component when it becomes exclusive due to the placement, location or function. Components show reactivity to presence or elimination of energy by becoming dormant, active to hyperactive.

Screenshot_2020-05-04 CAPE CANAVERAL, Fla -- At NASA's Kennedy Space Center in Florida media snap photos of space shuttle A[...]





Buildings have two major classes of systems: Structural and Non structural systems.



A structural system by its intrinsic nature, composition, position, or arrangement, provides a whole that stays stable, in equilibrium, or constant (yet may be mobile like a ship, spacecraft etc.).

The structural subsystems of a building system must exist in the required location or be available at the required moment and duration to achieve the distinctive constancy.

The stability of a building is disturbed, when the structural subsystems are repositioned or removed. Structural systems of a building are conceived for a range of behaviour, of combined profiles of stresses for Tension, Compression, or Torque.

Structural systems of the building seem to be well integrated, because by being together they achieve constancy, which is fundamental to a structure’s being.



Non structural systems of a building apparently have no or very little role to play in the constancy of the building. Subsystems within a building that do not affect the constancy of a building may be called non-structural systems, such as the partition walls, doors, windows, finishes, etc.

Non structural systems though useless in structural sense, are not totally dispensable. Many non-structural systems protect the structural elements, like plaster, walls, claddings etc. Some non=structural systems achieve their own stability by depending or subsisting on the structural systems, such as tensile forms like the stretched net or a sail. Non=structural systems need not be integrated with the structure, so are replaceable or relocatable.



1      Protective systems: Ones that cover the structural systems and non structural systems, e.g. plasters, waterproofing, roofing.

2       Filler systems: Those that fill up the gaps or spaces between structural subsystems, e.g. non load-bearing walls, joints.

3      Independent systems: These are complete systems by themselves that independently provide peculiar functionality, e.g. air conditioning, illumination, communication.


STONES for buildings

Post-by Gautam Shah



Stones like many other natural materials are abundantly available. Most of the rocks that we are likely to encounter and exploit are within the top 16 kilometres of Earth’s face. This mass is made up of 95% Igneous rocks, and rest consisting of widely spread cover of Sedimentary and Metamorphic rocks.


We today have greater capacity to search over wider terrains and also reach at sub surface locations. Exploitation of stones as collection from the surface or extraction from various depths is not a major technological problem, but economics of transportation limits its commercial usage.


There are 3 essential sources of Building Stone Materials:

● Surface collected stones

● Extracted stones: protruding and subterranean mass

● Waste and recycled stones

s3 Depositsteppes

The stones occur in many forms and sizes:

1 Large pieces which can be further down sized or cut into smaller units,

2 Units that are used without any other processing,

3 Pieces which are crushed or disintegrated into finer particles,

4 Rejected material from mining and collection processes,

5 Wastes from stone sizing and dressing operations,

6 Debris material recovered from demolition of old buildings and other structures.



Surface stones from single geographic region show qualitative and size variations of minor nature. Further quality equalization can be done by location-based sourcing, visual selection, grading, separation. Surface collected stones can be further quality equalized through many types of ‘processes’.

● Surface collected materials are naturally formed such as boulders, pebbles, gravel, sands, etc. These are very tough materials and equally weathered on all faces.

● Other surface collected materials are broken by natural disintegrating forces like weather, chemical reactions, land mass movements, internal stresses, etc. These stones may show up with varied weathering on their faces. Such materials are fractured along the plane of shearing force or across the weakest plane, and so show unpredictable structural properties, inconsistent colour and grain structure (texture) on different faces. These stones due to their long exposure are either the toughest remains or the weaker fractures. In the first instance further dressing or downsizing is difficult, and in the second case consistent shaping is not possible.

● Such materials are found spread or located over terrain difficult to access. Collection unless manual involves a large amount of useless mass.

s4 Naxos_Marble


Extracted materials are buried (loaded) under the same or different nature of materials’ mass. The over burdening mass protects, as well as contaminates the deposit. The water leaching through the organic soil burden is nominally acidic and affects the alkaline stone mass. Typically Lime stones when freshly extracted, are not exposed to Carbon Dioxide due to the overburden, and so are soft and porous, but begin to harden on aeration.

● Igneous and metamorphic rocks are not strongly stratified and do not present distinctive layers or strata. Sedimentary rocks are stratified, generally in horizontal layers. However, due to movements in the earth mass inclined and curved formations also occur. Sedimentary rocks show grains intervened by a cementing medium.

● Igneous and metamorphic rocks are often made of many different substances, some of these components, as remnants, are nearly crystalline compounds.

● Sedimentary rocks are comparatively formed of uniform constitution though with streaked colouration due to seepage of dissolved substances and stratification.

● Extracted rocks, require dressing, and often downsizing. The cleavage or fracturing during dressing and fracturing depends not only on the basic classification of the stone and also on constituent minerals such as silica, quartz, feldspar, mica, etc. These aspects also define the types of tools used for working and the nature of surface finish possible.


Igneous rocks, such as Granite and Trap are formed with the solidification of molten materials. Mineral gases and liquids penetrated into the stone and created new crystalline formations with various colours. Sedimentary rocks such as Lime stone, Sand stone, Soap stone Travertine, are formed from the bonding of deposition under pressure and heat over a very long period. Metamorphic rocks are formed by the transformation of igneous or sedimentary rocks, due to influence of heat or chemical action. Metamorphosed form of stones: Marble (of lime stone), Schist (of sand stone) and Slate (of mud-stone). Amorphous Solid is any material which does not have its molecules arranged in a lattice, or crystalline structure. Amorphous solids make up only 10 % of solids in the world. A well-known example of amorphous solid is glass, and that is why these solids are often termed glass. Amorphous solids’ structures have similarity to liquids, and so are also called supercooled liquids. Plastic is made from polymers, long strings of molecules purposefully chained together and is technically an amorphous solid. Crystalline Solids constitute nearly 90 % of all solids in the world. Crystalline solids have a lattice of molecules. The ordered pattern repeats substantially through the mass. Stones are classified as Siliceous when silica is the principal earthy constituent, Calcareous have carbonate of lime as the predominant material, and Argillaceous have alumina is the main component.





Stone extraction or collection creates large quantity of rejected and broken mass. Site based dressing and downsizing, are mainly done to reduce the mass for transportation, These generates large quantity of wastes. As stone sites are very remote from the point of use or application, it is uneconomic to transport and use such waste materials. Downsizing and cutting workshops located near urban localities, have an advantage that the wastes originating here have consistent one face or dimension. Machines that dress a block with rotary or stripe saws create wastes with smooth finish on one or more faces. Similarly slabs’ end or edge cuts have a uniform thickness profile. Stone polishing machines provide ground particles which are used as filler media.

Angular cut wastes can be tumbled with iron bits in a rotary drum to achieve rounded edged pebbles. Stone wastes can be used to create cement and resin-based composites, and for ‘synthesizing’.

s5 Lokotrack_LT200HP_mobile_cone_crushing_plant_(26373039712)

Stone buildings that are demolished in urban areas end up as debris for land fill for lack of man power required for separation and re-use. However, in rural area, it is possible to separate and reuse the material. Older stone flooring units are thicker in comparison to modern supplies. This can be split into two or more units and use the cut-face as the new face. Similarly masonry or building blocks can be cut to thinner blocks for use in cladding or surfacing. The advantage in reuse is free supply of mature (weathered-seasoned) stones.640px-The_Great_Mosque_of_Kairouan,_eastern_portico_of_the_courtyard.