Most of the materials required in building construction require a coating which is fulfilled by paints, varnishes, etc. Paint is a form of liquid that, on drying, forms a thin film on the substrate surface. The substrate can be concrete, wood, brick, plaster, metal, etc. It is applied in layers ranging from one to four layers to hide any imperfections of the substrate wall and protect from weathering action. Various types of paints are available in recent years with improved technology.

Applications and Uses of Paint :

• It can be applied to timber, brick, or on any other materials.
• The main function of paint is to provide protection or decoration or both.
  • Protect from weather, Sun, and rain and makes it waterproof.
  • Corrosion of Metals
  • Mechanical stresses
• Paints conceal imperfections on the surface and give surface protection.
• It increases the life of the surface or product.
• It prevents wooden structures from warping, checking, or decaying from termites, fungal growth, etc.
• Metals corrode if not painted at suitable intervals.
• Painting enables the masonry and concrete work to resist checking and disintegration, thereby extending life.
• It acts as a decoration and provides aesthetic value to the building.
• Paint modifies the reflection and transmission of light on a surface.
• Paints are also used as identifying any special equipment such as fire fighting lines are painted red to identify easily.

Qualities of Good Types of Paints

• Durable and long-lasting
• Ease of workability
• Surface coverage to be high with less usage of paint
• Uniform color and texture of paint on the applied surface
• Economical
• Withstand weathering action making it waterproof

Composition of Paint

Paint is composed of a base, pigment, organic binder, and additives.

Pigment – Solid ingredient of paint and is used in the form of fine powder. Pigments provide color for the finished product. Provides film adhesion and protects the substrate from corrosion, weather, and abrasion. Its characteristics are Opacity, Color, and Gloss.

Organic Binder – Liquid part of paint and it is called vehicle.

Additives – Modify the properties of the vehicle or pigment or both.

Commonly used Coatings:

• Applying the paint when the surface is dry is an essential factor to consider.
• A typical paint system consists of Primer and one or two top coats. Primers are applied directly over the bare surface to improve the adhesion of subsequent coats. Primer sealers and corrosion-resistant primers are the commonly used types of primers.
• Fillers are used to fill and repair porous substrates before applying a paint material. Concrete block fillers for masonry surfaces and wood fillers for hardwoods are applied. Wall Putty acts as a filler or sealer.
• Varnishes and Lacquer are commonly referred to as transparent finish.

Manufacture of Paints

• 1. Mix the basic ingredients in desired quantities.
• 2. Grinding the above mix of ingredients.
• 3. Thinning with solvent
• 4. Blending
• 5. Packaging

Types of Paints

The type of paints varies based on solvents, application, sheen, etc.

Types of Paints Based on Solvent

• Water-Based Paints
• Oil-Based Paints

Water-Based Paints:

The solvent or binder used in water-based paints is almost water

Pros:

• Low VOC emission
• Flexible and less susceptible to cracking
• More resistant to UV rays
• Can tolerate small amounts of moisture prior to application as it absorbs moisture.
• Takes less time to dry.
• Does not require a pre-treatment
• Stable color over time doesn’t become yellow

Cons:

• Lower sheen finishes when compared to oil-based paints.
• Less tolerable to different variations in weather conditions.

Oil-Based Paints:

Oil-based paints use an organic solvent typically the mineral turpentine.

Pros:

• Good for high moisture rooms.
• High durability and rich finish/sheen.
• Excellent resistance to wear and tear.
• More tolerant to differing weather conditions.
• Brushstrokes fill themselves-no strokes seen appearing smooth finish.

Cons:

• Less flexible, likely to crack, become dry, and brittle over time.
• High toxic emissions (VOCs)may lead to health issues.
• If moisture is present on the surface, oil paints repel and do not create a strong bond. Therefore, the surface has to be completely dried.
• Take longer periods to dry.
• Turns yellow over time.

Types of Paints Based on Composition and Usage

• Interior
• Exterior
• Wood
• Metal

Interior Paints

Distempers

They are water-based paints and are most commonly used on interior surfaces. Distempers are the oldest and cost effective paints. These paints have a distinctive odor composed of lime, chalk, and water. They are easy to apply, durable, and generally give a rustic finish compared to emulsion paints.

• Dry – It is available as a dry powder and water is to be added before applying.
• Synthetic – includes drying oils which help in increasing coverage area.
• Acrylic – It has an acrylic co-polymer formulation

Plastic Emulsion

These paints are water-based paints and give a silken smooth finish with no odor. Expensive and more durable than Distempers. A wide range of colors are available. It has scratch resistance and anti-fading properties.

• Regular
• Economy
• Silk

Exterior Paints

Cement Based Paints

Type of water paint in which white or colored pigment and cement form the base. Applied to exposed or plastered brick masonry and concrete work. It is weatherproof.

Textured paints

Composed of cement, gypsum, sand, metal, and binders. The coarse grains of gypsum and sand give a rough texture to the wall. Distinct designs and styles can be created with different kinds of textures.

Acrylic Emulsion

In acrylic paints, pigments are suspended in acrylic polymer emulsion. These paints dry fast.

Wood

PU (Polyutharene) & Melamine

Protects timber from ultra-violet light and is durable with high resistance.

Varnish

They are combinations of resins and oils/modified alkyd resins. Varnish helps to reveal wood grains thereby retaining natural wood color and enhancing it.

Metal

Enamel Paints

They are oil-based paints. Made by adding pigments like white lead or zinc white to a varnish binder. Stand well with the adverse effects of the atmosphere.

• General purpose
• Synthetic
• Premier

Other Types of Paints

Aluminium Paints

• Used for woodwork and metal surfaces.
• Made by a mixture of aluminum powder and quick-drying spirit varnish/slow-drying oil varnish to suit the requirements of the surface.
• Weather-resisting and waterproofing qualities, resistant to the corrosive action of seawater.

Bronze Paints

• Mostly used for painting interior or exterior metal surfaces commonly applied on radiators.
• High reflective property.

Anti-Corrosive Paints

• Used as a metal protection paint for preserving structural steelwork.
• Prevents from the effect of acids, fumes, and corrosive chemicals, resistant to rough weather conditions.

Asbestos Paints

• Especially suitable for patchwork or stopping leakage in metal roofs.
• Used for painting gutters, flashings, etc. to prevent rusting.

Bituminous Paints

• Used for painting underwater structures, exterior brickwork, and plastered surfaces.
• Alkali resistant and provide protection from iron and steel.

Rubber Base Paints

• The paint is made from rubber treated with chlorine gas which is dissolved in suitable solvents and mixed with other pigments.
• Excellent acid, alkali, and moisture-resistant properties. Commonly used as a protective coating on cement concrete floors, and interior or exterior masonry surfaces.

Cellulose Paints

• Paint is made from celluloid sheets and amyl-acetate substitutes.
• Stands well in rough weather conditions.
• Hard, flexible, and smooth.
• Due to its high costs, restricted to motor cars/vehicles.

Casein Paints

• Casein is a protein substance extracted from milk curd which is mixed with a base consisting of white pigment.
• High opacity.
• Usually applied on walls, ceilings, wallboards, and cement blocks to enhance the appearance of the surface.

Types of Paints Based on Finish/Sheen

Flat/Matte Finish

• The low gloss and non-reflective finish (low gloss paint sheens absorb light).
• Mostly used for interior walls and ceilings of living, bedroom, dining, etc.
• Perfect for low-traffic areas.
• Hides imperfections like chips or cracks in walls.
• Hard to clean handprints and other marks.
• Requires less no. of coats than glossy finishes.

Eggshell Finish

• Low sheen, soft and velvety smooth like an eggshell.
• A kind of sheen between satin/glossy and gives a beautiful classic look.
• Perfect for low to mid-traffic areas.
• Have little reflectivity.

Satin Finish

• Provides a pearl-like smooth and velvety finish.
• Easy to clean than low gloss finishes and resists chipping and peeling off.
• Works well in high-traffic indoor areas.
• Reflect a bit of light.

Semi-Gloss Finish

• Shiny than a satin finish, smooth and sleek.
• Less reflective than glossy finish and more reflective than matt and eggshell finishes.
• High resistance to moisture, suitable for high-traffic areas.
• Bathrooms, kitchen cabinets, doors, windows, etc.
• Highlight imperfections on walls.

Gloss Finish/High-Gloss Finish

• High reflective and glass-like finish (high gloss paints reflect light).
• Suitable for high-traffic areas.
• Highlight imperfections on walls clearly.
• Common for furniture, cabinets, decorative trims, etc.
• Used on interior and exterior wooden moldings and metal surfaces.

Paints Application Method

The most common types of paints application methods are

• Painting with Brushes
• Spray Painting
• Roller Painting

The proper application of paints depends on several factors such as

• Surface Preparation
• Material selection
• The skill of the applicator
• Environmental Conditions
• Temperatures

Commonly Used Type of Paints Materials

• Paint – Easy to apply, often used on large and small wall surfaces. Flat, low-luster sheen.
• Enamel – Dries out fast, commonly used on small and smooth surfaces. Semi-gloss and High-gloss sheen.
• Stains – Generally used on wood surfaces, change the color of a surface and protect by penetrating the surface.
• Varnishes – Homogeneous mixtures of resins, oils, driers, and solvents.
• Lacquers – Dry quickly, film-forming solutions; mostly used on automobiles or furniture.

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