CLEAR versus PIGMENTED COATINGS

Post 553  by Gautam Shah

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Paints have colourants or pigments to cover a substrate and provide new colour. Pigmented coatings constitute the largest section of coating production. Clear coatings, however, provide a see-through film on a substrate, which in additionally endow spacial surfaces, textural and other properties. Clear and pigmented coatings have been concurrently in use since prehistoric times. Both types of coatings usually have similar film forming substances, though the techniques of application and purposes these are employed are distinct. Pigmented and clear coatings, both can form the primer coat or a top coat in a multi coat system. As a primer or first coat the clear coat penetrates micro pores and seals the surface. As a top coat a clear finish endows specific surface quality such as gloss, sheen or matt finish and protection. In a multi coat system a pigmented undercoat creates a colour-equalized surface.

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Wikipedia image

Pigmented coatings, besides colourants like pigments and dyes, have many other substances that add special effects through opacity. These are metal powders and flakes, prilled materials, micro sized lints of glass and polymer fibres, glow powders for phosphorescent, luminescent or photo-luminescent effects. Pigmented coatings usually contain extenders for several purposes. Extenders are minerals of low refractive index. Pigmented coatings for rendered or textured finishes have high solid build resins, additives or false viscosity enhancers and minerals and fillers.

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Clear Coating of Shellac Wikipedia image by Simon A. Eugster

Clear coatings are translucent to transparent, which are natural properties of the resin (film forming substance) or through additives like dyes and very low refractive materials. The need for a clear coating could be functional, such as avoidance of pigment for being unnecessary, toxic, or reduce the bulk of the film and thereby better homogeneity and lesser thickness. Clear coatings offer glossy to dull types of surface textures, and provide shades like tinted, crystal clear or water white. Surface texturing like hammer-tone, wrinkling, crackled, streaking, are also achieved. Clear coatings applied to emphasize substrate colours, grains or patterns as in case of timber, leather, paper metals or fabrics. Clear coatings are applied where for any technical reason it is not advisable to colour a coating, as in case of toys, food cans, etc. Large number of clear coatings are technical applications for rust inhibition, water proofing, static resistance, etc.

Some of the crudest forms of applying clear coatings, are still practised, and these are surface wetting with plain water, waxes, oils or tallow surfacings, starch sizing, gum and other plant exhudents surfacing, milk, and casein coatings. These materials are hydrophilic, and many run in moist weather, collect dust and are vulnerable to fungus attack.

A better alternative for creating clear coating, has been the use of distilled and modified pine tree extracts like rosin. Calcium and zinc modified rosins which are soluble in turpentine were used for cheap quality toys, country furniture and electrical wooden boards and battens. Often raw senna, umber, ochre and dyes like metanil yellow are added to these for colour toning and hide the ugly grain and defects of jungle woods. The finish has very little resistance to wear and tear and slightly softens up in moist weather.

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Pigmented coatings are used on sites, in industrial production units, by amateurs, artists, and crafts people. These coatings are applied with crude or rudimentary methods and also through high-tech facilities. Pigmented coatings contain specific minerals and other substances as pigments and extenders for rust inhibition (zinc), water resistance, electrical properties and fire resistance (such as walstonite), anti fouling agents.

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Wikipedia image by Baminnick

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Pigmented coatings are of following basic classes:

1. Architectural finishes

  • Water-based masonry finishes
  • Other masonry finishes
  • Non masonry finishes applicable on sites

2. Industrial finishes

  • Solvent-based systems
  • Water-based systems
  • High solid coatings and powder coatings
  • Air drying systems, Low and High Temperature baking systems, Catalyst systems

3. Other types of pigmented Surface Finishes and Treatments

  • Marine coatings
  • Road marking systems
  • Toys’ and plastic colours
  • Leather colours
  • Body colours and make-up utilities
  • Inks

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SELECTING and APPLYING a COATING

Post 552  by Gautam Shah

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Nepal painters Flickr image by Wonderlane

Coatings are selected in consideration of the substrate (virgin or already coated surface), application technology and atmospheric conditions. Commercially coatings are available for broad categories of surfaces, such as masonry, wood, metals; for specific layering such as primer, undercoating, top or finishing coating; for purposes such as architectural, industrial, marine, clear coatings, food-grade; for technical applications such as water-proofing, insulating, mastic compounds, fire-retardant or proofing, conductive or anti-static etc.

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Wikipedia image by Biswarup Ganguly

Selection of a Coating is done in view of following factors:

  1. Appearance (colour -hue, tone) (texture -sheen, gloss)
  2. Weather properties
  3. Abrasion resistance
  4. Adhesion to the substrate
  5. Impact resistance
  6. Flexural qualities
  7. Recoatability
  8. Drying time (touch dry, hard dry or use ready)
  9. Feasible drying techniques ( Air dry, baking, catalytic)
  10. Resistance to a given medium (sea water, alkaline or acid, chlorine and sulphur)
  11. Resistance to sunlight (direct sunlight and UV component)
  12. Antistatic properties
  13. Temperature resistance
  14. Odour
  15. Solvent vapour hazards (VOC)
  16. Ecological value
  17. Application environment (open, enclosed, controlled, inclement)

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Wikipedia image by Vermont Timber Works Inc.

General Rules of application

Many of these rules are more pertinent to Alkyd resin-based coatings, rather than Latex or Plastic polymer-emulsion-based coatings. Both often contain anti-settling agents that retard the separation of solids from liquid components. The Plastic paints now contain thixotropic agents that induce false viscosity when the coating material is at rest, but once stirred temporarily gains normal or applicable viscosity.

1 The tins, drums, carboys, Jerry-cans of coatings, primers and undercoats should be delivered on a site, at least 24 hours before the job and allowed to rest, and revert to the site temperature.

2 All packing of coating materials, except solvents, should be placed upside down for at least 24 hours, prior to the job (relevant for An Alkyd resin based pigmented coatings or oil paints, primers etc.)

3 Always draw just sufficient material that can be used immediately (-if enamel, preferably within an hour, and, -if lacquer, much shorter duration).

4 Do not pour back any colour that has been drawn out and exposed to the atmosphere. Before closing a partly used tin, pour a small quantity of miscible solvent or thinner over the surface to prevent skinning and evaporation of volatile substances.

5 Atmospheric conditions should normally remain consistent (ideal temperature range between 10°C to 35°C, humidity 50% and breeze velocity at 20 km per hour) for the entire duration of application, and curing or drying. The surface to be coated must be at the ambient temperature. All direct sun-rays (even for exterior coatings), except of the early morning, should be avoided for the entire period of application and till the coating is `touch dry‘.

6 Tint the undercoat slightly lighter than the final coat to differentiate and ascertain the full coverage by the final coat.

7 Where very light shades (`off whites‘) are to be mixed on a site, first reduce the tinting-paste with a small amount of white paint, and then adjust the final shade with the reduced tinter. To match a very light shade, place a drop of mixed trial colour on white paint wet-surface, and judge the difference. Certain high tinting pigments, such as blue, black and red are required in extremely small portions, and are difficult to mix in base white or lighter shade. Such coatings turn out to be slightly darker and sometimes have streaks, because brushing or rolling enhances the dispersion of pigments. To avoid this it is better to filter out all the site-mixed colours with a Nylon or Polyester fine-mesh cloth (bolting cloths, used for making screens for screen printing).

8 Water based coatings, dry out to a lighter shade then their wet look and Oil or resin-based coatings dry out to a darker shade then their wet look.

9 Never apply a very thin coat, or a thicker coat, than recommended by the manufacturer.

10 Apply the first coat in the direction of fibres or texture grains of the substrate. Apply the next coat in the cross direction, observing that the final coat on vertical surfaces is always in a vertical direction. It is always better to apply the final coat in direction of length then width.

11 Allow sufficient time for each coat to thoroughly cure or dry out, before any new coating or treatments (like sandpapering, rubbing) are done. Learn to differentiate between a `touch dry’ and ‘through dry’ conditions of a coating. Convertible coatings1 should not be re-coated before these are thoroughly dry, but Non-Convertible coatings2 can be re-coated when substantial part of solvent material has evaporated. Non convertible coatings can develop an inter layer adhesion. Both types of coatings, though may not be brush coated before through drying. Non-convertible coatings, however, may be re-coated by spray method.

12 Allow sufficient time before the coated object is used for intensive service (quite often it may take 7/15 days after `through dry’ conditions), because it takes longer for the inner section of coating to become thoroughly dry.

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Marine Painting

*(1) Convertible Coating > The film forming substance on drying or curing coverts itself into a different material, which cannot be reverted by any process like solution, heating, etc.  Dried out Oil paints cannot be dissolved.

*(2) Non-Convertible Coating > The film forming substance on drying can be reconverted into original like material by solution or heat softening. NC Lacquers are such coating materials.

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DAYLIGHTING

Post 551  by Gautam Shah

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Daylight has Four important facets, the illuminance, warmth, colour and the variability. Each of these becomes a key issue for building design, how we conduct tasks and manage comfort. The chief source of daylight is the sun. It offers direct and indirect (‘diffused’) light. The earth’s daily rotation on inclined axis and elliptical rotation around the sun offers the variations, beyond the frequent changes in sun’s own output. Sunlight at Earth’s surface is around 52 to 55% infrared (above 700 nm), 42 to 43% visible (400 to 700 nm), and 3 to 5% ultraviolet (below 400 nm) spectrum. The quality of daylight at each place and moment is distinctive, creating unique time, space and environmental combination.

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Grand Station NY The natural flood of daylight is no longer available due to  high-rise buildings in the vicinity 

Daylight is the combination of all direct and indirect sunlight available outdoors during the daytime. Daylight as a natural light is considered mainly during the sunup to sundown period (and little more for the twilight periods). The amount of natural light available in any interior space is proportional to the daylight available outdoors. Daylight on an outdoor location is a combination of direct sunlight, diffuse sky radiation, and both of these as reflected from the earth and other objects. Light scattered in the atmosphere is referred to as diffused daylight. Sunlight scattered or reflected from other space objects, such as the moon is not considered daylight.

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Lighting without a window in the Pantheon Rome

Direct sunlight is that part of solar radiation which reaches the earth’s face without being scattered. It is a directed beam or a point source of light. Direct sunlight at noon can have illuminance as high as 120,000 lux (Compared to this moon light is <1 lux). Sunlight is a warm colour light, at noon, the colour-temperatures are about 5500°k, bluish-white or ‘cool colours’, and at sunset, these are about 2700-3000°k (degrees kelvin), are yellowish-white through red or called ‘warm colours’. This is similar to heated iron, like a horseshoe, it first glows red, but on further heating it turns to orange to yellow to white and, finally blue-white.

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Colours at sunrise due to temperature differences

Daylight consists of direct sunlight and it’s reflected or diffused component. Daylight arrives or disappears when the Sun is approximately 18° below the horizon. (As the Earth takes 24hoursx60=1440 minutes to complete its orbit of approximately 360°, the 18° translates into 72 minutes period on equator and 23°N to S. For different locations and seasons the twilight time could vary). This is a twilight zone of early or late day lighting, when the Sun itself is not visible, as it is below the horizon. Twilight occurs due to the scattering of sunlight in the upper atmosphere, which in turn illuminates the lower atmosphere. This is a period when shadows are not yet present, and objects are silhouetted against gradually brightening sky. In extreme regions like the arctic where Sun may not dip below 18°, the twilight may be seen between evening to morning night period.

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Three types of twilight within 18 degree –Wikipedia image by TWCarlson

The twilight effect is important for the stretched daylight period. It defines when street and other estate security lights can be switched on or off. It defines when certain outdoor activities like jogging, and exercises can be conducted. Interior areas of a building begin to receive illumination in the twilight period (near sunset or sunrise), allowing for switching on or off the artificial illumination.

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Golden gate bridge at Twilight Wikipedia image by Brocken Inaglory

A twilight zone has been accepted as a prayer time in many religions. Egyptians wished to experience the first rays of the sun, for these obelisks like tall structures were erected near the temple entrance. The tapered top face of an obelisk was covered with shiny metal to glitter in the first sun rays of the day. Similarly Buddhist and Hindu temples used columns topped with shining metal sculptures like Dharma Chakra or Toran of metal pieces. A twilight zone is the time when cattle go out or come back from grazing, raising dust in the sky. This Go-Dhuli period is considered the most auspicious time for Hindus.

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Twilight zone is cattle returning home after grazing with dust rising (GoDhuli time) -most auspicious period for Hindus India

Direct sunlight can warm up a surface depending on its angle and duration of exposure to the sun, surface colour and texture. Direct sunlight is the brightest illuminance and can be redirected through reflection to interior spaces by means, such as opaque reflectors, mirrors, tubes etc. It is used for generating electricity through solar panels. Direct sunlight casts a shadow, whereas diffused sunlight is scattered and arrives from all directions, so does not cast a distinct shadow. But, often enough diffused light arriving through highly directional openings, casts a dull shadow.

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Skylight in Star Ferry pier Hong Kong Wikipedia image by VictoriaDFong

Day-lighting is used for illuminating a dully lit space or object by use reflective surfaces, appropriate spatial orientation or exposure, time scheduling or through design and placement of openings. The primary intention is to save fossil and other sources of energy, better recognition, reduce the glare, adjust the contrast and for highlighting.

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Stratification of openings for Illumination and view II nd floor Children Library Bronx Library Center Wikipedia image by Julian A. Henderson

Daylight design takes into consideration the source and nature (intensity, colour) of the direct and diffused sunlight. One of the important holistic aspects of daylight design is the stratification of openings for illumination, and for view in and out. Stratification arises from the fact that daylight is arrives from the skies and grounds, both of which are strongly horizontal in effect. Daylight design is conditioned by the tasks to be handled, building form, siting, climate, architectural components and appendages, surface colours and textures in interiors, back up system of artificial illumination. At micro level design criteria include the opening size, shape, orientation, location, quality of glazing, opening treatments, position and orientation of interior components.

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FOOD PREPARATION AREA

Post 550  by Gautam Shah

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Dolly Johnson, personal cook to President Benjamin Harrison, in the small white house kitchen 1890

The human abode is focussed on the position of food preparation area. Oxford’s dictionary defines the focus, (originally a Latin word), as the hearth. The hearth, food preparation and mother, designate a home. Food preparation is just a slot in a time schedule with a casual occupation in space. Its task utilities, though are sited everywhere in the dwelling. Food preparation and related utilities are continuously shifted to exploit the environment, social needs, fuel management, built form, etc. as available within and without the precinct of a dwelling. Food consumption has been diversely connected to the food preparation area, mainly due to the discomfort of emissions from fuels of the hearth and secondarily the changing pattern of social relationships. As the dining moved away, the kitchen began to be neglected. The kitchen was likened to a dungeon, an un-owned or non-personal space, managed by a retinue of servants. The quality of food and related services failed to impress the guests. Compared to this, the participatory kitchens of crafts’ person or farmers were lively spaces.

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Sudanese woman preparing traditional bread Kisra Wikipedia image by Mohamed Elfaith Hamadien

 Some Blog links on related topics:

FOOD PREPARATION SYSTEMS – I
https://interiordesignassist.wordpress.com/2014/10/14/food-preparation-systems-i/

FOOD PREPARATION SYSTEMS – II Kitchen and its place in the house
https://interiordesignassist.wordpress.com/2014/10/15/food-preparation-systems-ii/

FOOD PREPARATION SYSTEMS – III Kitchen and evolution of its Facilities
https://interiordesignassist.wordpress.com/2014/10/16/food-preparation-systems-iii/

FOOD PREPARATION SYSTEMS – IV Hearth and Kitchen
https://interiordesignassist.wordpress.com/2014/10/17/food-preparation-systems-iv/

FOOD PREPARATION SYSTEMS – V   (Kitchen Fire)
https://interiordesignassist.wordpress.com/2014/10/24/food-preparation-systems-v-kitchen-fire/

FOOD PREPARATION SYSTEMS – VI -Kitchen Design by Fires
https://interiordesignassist.wordpress.com/2014/11/19/food-preparation-systems-vi-kitchen-design-by-fires/

FOOD PREPARATION SYSTEMS – VII -Kitchen facilities and tasks
https://interiordesignassist.wordpress.com/2014/12/12/food-preparation-systems-vii-kitchen-facilities-and-tasks/

KITCHENS in DWELLINGS
https://interiordesignassist.wordpress.com/2015/01/21/kitchens-in-dwellings/

COOKING and DINING
https://interiordesignassist.wordpress.com/2015/03/12/cooking-and-dining/

KITCHEN and its shifting position
https://interiordesignassist.wordpress.com/2015/04/01/kitchen-and-its-shifting-position/

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Roasting, medieval illuminated manuscript (Tacuina santatis casanatensis 14th C.)

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SPATIAL INTIMACY

Post 549  by Gautam Shah

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Intimacy is an individualized notion with primary concern for survival. Survival is a biological necessity. It is a defensive reaction where one tries to create a protective shield by distancing and sensorial indifference. It is also an offensive activity where to reduce the chances of physical (sexual, emotional) attraction one avoids person to person encounter, or tries to be part of a crowd. Manifestations of Intimacy are proximity, sensorial recognition and vulnerability, lack of protective cover for privacy and familiarity with people and objects. These are also important features of spatial experience. And, yet intimacy and space are not mutable.

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TV host Jon Stewart being intimate by being closer to the guest

Intimacy is an attitude, mental conditioning or mental posture. It is a feeling of closeness or affinity with a person or an object. It relies on compatibility, sexual needs, glandular secretions, social acceptability etc. Meaning of intimacy varies from relationship to relationship, and within a given relationship. Intimacy is both the ability and the choice to be close, loving, and vulnerable. Intimacy could be one-way feeling that is without reciprocal feeling. One can feel close to a person who is long dead -an illusory presence, or through notional links (clothes, odours, recorded sounds, etc.). So intimacy is not always a function of physical proximity or spatial distancing.

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‘Proposal’ by artist William -Adolphe Bouguereau 1825-1905

Intimacy can have two main forms: emotional intimacy and physical intimacy. There could be other forms of empathy like cultural, intellectual, spiritual, social affinity that are akin to intimacy in some conditions. Intimacy has more to do with rituals of connection. Strategic relationships developed to take advantage of someone could be very intimate, but it is make-believe closeness.

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Crowding in trains Wikipedia image by author Jkamyiu

Intimacy and privacy, both are expressions of behaviour in a space, but former is not dependent on quality of space but later is substantially a product of space configurations. Privacy helps intimacy, but one can be intimate with a person or group of persons even without any apparent need for privacy. Intimacy is attitudinal positioning to control ingress, distraction and unwanted engagements by others.

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Friendship and intimacy Wikipedia image by author Fernando de Sousa

Privacy and intimacy both are affected by the notion of distance. For privacy one resorts to physical distancing or barricading, but intimacy is a perception of interactions with other beings and objects. The distancing for privacy is in terms of space form, size and shape, intervening objects, physical reach and sensorial perceptibility. The perception of proximity for intimacy is factored by environmental factors, biological need, social requirements, communication, expression, psychological make-up, time duration and the relevance of objects and people.

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‘Peasants playing cards by artist Hendrick Martensz Sorgh 1610-1670

A person projects privacy and intimacy concurrently, but in various proportions. The space facilitates different levels of physical closeness, isolation and insulation, however the mental needs ultimately define the degree of involvement. The culture defines the acceptable or inappropriate types of intimacies. A crowded stair, elevator, metro carriage, do not project an intimate environment. A handshake or hug nominally has no sexual connotation in many cultures. In some cultures, a veil is considered private enough to be retardant of intimacy.

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Women in Shiraz, Wikipedia image by author Zoom Zoom from Beijing

Two persons or members of a group can talk in whispers and give out an impression of intimacy, in spite of the apparent distance between them. Conversely talk-discussions in high pitch could be used to present bonhomie, and thereby a non-intimate encounter. Politicians and celebrities talk in whispers to state things that need to be made public and talk loudly things that need not be public. A public orator changes the pitch from normal to very low to be intimate with the audience.

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VERANDAHS and equivalent architectural forms Part – II

Post 548  by Gautam Shah

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Verandahs are compared to Antaravedi, a land between two rivers -a Doab. A verandah is a territory between a public and a private domain. The duality of the verandah persists through its many different forms across climates and cultures. The usage varies from intensively participatory space, a shading device to a decorative appendage. Verandahs or similar architectural spaces have been placed on outer faces and also on inside face abutting the inner courtyards or chowks. These spatial entities have been ‘embryonic elements’ that have formed spaces and activities into a cohesive organization.

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Old Government house Brisbane Wikipedia image by author Kgbo

The built-form of rooms protects, but as an enclosed space it becomes sometimes oppressive enough, for need to transgress it. Walls are removed and roofs are punctured to connect to the outside or other spaces. The change is brought in or the space reaches out. The openings create a hierarchy of spatial zones, a remote or inner zone close to the wall, and a series of gradually varying environments of ‘internal openness’, and ‘external vulnerability. The spatial privacy and intimacy are passing and subjective, but not dependent on the spatial formations.

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Verandah of House of Indian author SaratChandra Chattopadhyay Wikipedia image by author Biswarup Ganguly

A verandah has had many architectural configurations. A lean-to like shade overtly attached to the shell of a building remains a casual expression for escape from the enclosed space. It is open on three sides as a transition space between interior and outdoor spaces. The low level of edge eaves frames the view. Such lean-to shades perambulate the house to provide shade and cover from the rains. It is a transition area between the public and private sections of the building, and circulatory space to access rooms that are often internally and intentionally unconnected, such as guest rooms, home office, food preparation area (Babarchi-khana), etc.

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The Iwan space of Negar Khane, Golestan Palace, Tehran, Iran Wikipedia image by Author Philippe Chavin (Simorg)

 The verandah, of the mid-east architecture, the Iwan becomes the most important space for interactions, making the rest of the building a subdued refuge. Iwan or Liwan (Iwan with al prefix) relates to an old Persian word a-pad-an (appadana) standing for unprotected place (referring to the veranda-shaped structure open to the outside elements). A similar word in Sanskrit ‘apadana’ means ‘to arrive at‘. The Persian Apadana was a structure in as part of the palace buildings at Persepolis, with open verandas with columns on three sides. The columns and ceiling were replaced with a barrel vaulting, in Parthian and Sasanian architectures. This aywan of the post-Islamic architecture is a veranda, open on one face. A Riwaq is a longer or stretched out arcade or portico for transition, open on at least one side.

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Iwan of Ameri House in Kashan, Iran Wikipedia image by author Matthias Blume 

The traditional houses of mid-east regions have a multi-functional core space with distinctive spatial quality. The space offers controlled brightness and protection. It is more of a participatory space, and less for transition or circulation area. The space (till now) was for family engagements beyond the gender considerations. Such house forms with varied spatial arrangements, in various languages of the region, called as ‘tarma’, ‘riwaq’, ‘talar’, ‘ursi’, ‘hosch’ ‘sofa’, ‘eyvan’, ‘hayat, ‘lywan’, and ‘apadana’. These multi-functional core spaces are not outward transgressions but inward scoops incised from the shell of the built form. The front has been with and without columns, roof flat or vaulted, and the space height from single to multiple floors.

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Eram Garden Shiraz, Iran, Wikipedia image by author Arad

The typical Iraqi Tarma house is sited deep into the plot, with a largest possible courtyard in front of the Iwan space. The central space of the Tarma house is an atrium called as ‘hosch’ in Arabic. Tarma house courtyard has been often compared to A Roman atrium house (Also called Roman compliviatum). A Tarma house courtyard is open on all sides except for intentionally but separate buildings or neighbouring properties. A Roman atrium house, in comparison has a centrally located courtyard, well defined on all sides. Roman atrium side spaces can be compared to the Osari or Parsal spaces that abut a central courtyard called Chowk. Osari is a verandah or small Liwan like space with or without columns, on one or many sides of the courtyard. The Osari oriented to different directions and house elements (such as kitchen, entrance, water-storage, etc.) serves different purposes.

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Reconstruction of Roman Atrium house for an exhibition in the Boboli Gardens Wikipedia image by author sailko

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MASONRY PAINT FINISHES

Post 547  by Gautam Shah

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Akal Takht at Golden Temple Amritsar India Wikipedia image by Author Amarpreet.singh

Architectural finishes are coatings or paints that are more often than not, applied on the site, before and after the elements have been assembled as an architectural entity. These usually dry out at ambient temperatures -air drying, i.e., are non baking types. Architectural finishes, in comparison to industrial coatings are high pigment & extender build coatings. Substrates for architectural coatings are of THREE basic categories, 1. masonry, 2. wood, wood composites and fibrous surfaces 3. metal. In few instances architectural finishes are also applied in the industrial set-up, over systems, components and parts.

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Colourful Homes at Burano Italy Venice Italy, Image attribution W. Lloyd MacKenzie via Flickr @hhtp://www.flickr.com/photos/saffron_blaze/

Masonry structures are in the form of straight or inclined walls, columns, piers, abutments, and occasionally on roads, curbs and floors. A masonry structure could be made up of unitized blocks of compacted clay, stones, cement concrete or baked clay or bricks with their patterns of joints and joining materials. Masonry surfaces may have plasters of plain or rendered faces of clay, pozzolana, lime or cement, all strongly alkaline in nature.

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Wall texture rendering Wikipedia image by Biswarup Ganguly

Masonry finishes, are of TWO basic classes: Exclusively protective coatings and Decorative finishes. Few commercial finishes provide both the qualities. Decorative finishes may be sub-classed as Interior and Exterior coatings, where the later category may offer substantial protection advantages.

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Roof coating Wikipedia image by Waller42

Masonry surfaces cover very extensive area, and so water has been the ideal vehicle for formulation and also as an application solvent material. It is abundant and cheaply available and is non toxic. Water as a vehicle, however, has no binding characteristic, and for that reason many natural and synthetic adhesive type of gums and resins are used as binders. Where such substances are not dissoluble in water, various water-based emulsions are used. Latex paints or emulsion type plastic paints form the main section of such coatings for masonry finishes. On removal or evaporation of water, the film formed maybe substantially moisture or gas impermeable, or a permeable lattice in the form or water repellent coating.

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Brighton Beach Melbourne Wikipedia image by Beau Wade

Voids over masonry surfaces are partially filled or levelled, causing a change in texture of the surface, when such coatings are loaded with pigments, extenders and fillers. In few instances this is unavoidable, but in many cases improvised `architectural’ or `rendered’ effects are intended. Fillers for such `rendered’ coatings include natural or treated mineral particles, quartz and silica sands, mica dust, glass and polymer beads, metal-dust, flakes, chips, or shavings.

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Iron Oxide wash houses Pakenham st Shaftesbury square, S Belfast Wikipedia image Jeanne boleyn

 Some of the architectural coatings are:

LIME-WASH

CEMENT PAINTS

CEMENT SURFACE FINISHES

OIL BOUND DISTEMPERS -OBD

DRY DISTEMPER or CALCIMINE

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Blue City Jodhpur, Rajasthan, India Wikipedia image by michael clarke stuff

Among the other masonry finishes, water proofing finishes constitute a major section. Such coatings are either `technical’ coats or part of multi purpose coatings. Technical coatings, impermeably seal the surface by covering all voids, pores and crevices; or cover the surface in the form of a lattice that is non wetting and so water repellent. In the former case the coatings are used where water vapour pressure is low and where a change in texture (due to filling up of voids ) is allowable, or desired. In the second case, texture properties of surfaces remain more or less intact, while the water repellence is provided by the ionic quality of the surface. Commercial water proofing coatings are based on Bitumen, epoxidized bitumen, PU coatings, silicone paints, and polymeric compounds.

Good film properties on masonry surfaces are achieved by using 100 % acrylics, or copolymers of ethylene, or acrylic esters, emulsions of vinyl copolymers. Chlorinated rubber with a suitable plasticizer, has a good alkali and atmospheric contaminant resistance. Long oil alkyd enamel with appropriate primer system work well for masonry surfaces.

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Deck Floor marking paint

 Floor paints

Floor paints are used to improve the appearance, increase abrasion resistance, reduce moisture penetration and impart spillage proof qualities. Medium oil alkyds and moisture cured polyurethane, epoxy compounds, chlorinated rubber coatings are used. Road marking and curb coatings are very similar to floor paints except that in certain cases reflective or fluorescent pigments are used. Hospitals, operation theatres, pharmaceutical and electronic assembly plants, require joint less flooring and wall-finishes for bio-pathological reasons, or for dust less environment. Such finish systems are made from of chlorinated rubber, urethane or epoxy coatings. Wood or wood composite floorings in athletic and indoor sports area require a smooth, non skidding and spillage proof coating. Such coatings consist of melamine, urethane or epoxy materials.

FLOOR PAINTS

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