Masonry and plastering are fundamental construction trades that define the structural integrity and aesthetic appearance of buildings. This training module covers comprehensive techniques for brick/block masonry and various plastering methods to ensure quality workmanship and durable finishes.
Training Duration: 2 weeks
Prerequisite Skills: Basic knowledge of construction materials, hand tools, and safety procedures
Various types of bricks and blocks are used in construction based on strength requirements, aesthetic considerations, and local availability.
| Type |
Dimensions (mm) |
Compressive Strength |
Best Used For |
| Clay Bricks |
230 × 110 × 70 |
3.5-35 MPa |
Load-bearing walls, facades |
| Fly Ash Bricks |
230 × 110 × 70 |
7.5-10 MPa |
Eco-friendly construction, interior walls |
| Concrete Blocks |
400 × 200 × 200 |
3-8.5 MPa |
Rapid construction, partition walls |
| AAC Blocks |
600 × 200 × 200 |
3-4.5 MPa |
Lightweight construction, thermal insulation |
Mortar binds masonry units together while accommodating minor movements. Different applications require specific mix ratios.
| Type |
Mix Ratio (Cement:Sand) |
Strength (MPa) |
Application |
| M1 (Type O) |
1:6 |
2.4 |
Interior non-load bearing walls |
| M2 (Type N) |
1:5 |
3.6 |
General purpose, above grade walls |
| M3 (Type S) |
1:4 |
5.2 |
Below grade, retaining walls |
| M4 (Type M) |
1:3 |
7.5 |
Heavy loads, foundations, retaining walls |
- Trowel: For applying and spreading mortar
- Mason's level: For checking horizontal and vertical alignment
- Plumb bob: For ensuring vertical alignment
- Tape measure: For measuring dimensions
- Mason's line & pins: For maintaining straight courses
- Brick hammer: For cutting and shaping bricks
- Mortar pan: For holding mortar during work
- Jointer: For finishing mortar joints
- Corner blocks: For maintaining plumb corners
- Wire brush: For cleaning bricks and joints
Material Quality: Always check bricks for cracks, proper shape, and uniformity. Reject any damaged units before starting masonry work.
- Verify layout and dimensions according to drawings
- Clean foundation or slab surface thoroughly
- Soak bricks in water for 2-3 hours before use (except AAC blocks)
- Prepare mortar in appropriate mix ratio for the application
- Set up mason's line and corner blocks for alignment
- Establish reference points for doors and windows
- Apply damp-proof course if required (basement/ground floor walls)
Masonry bonds determine the pattern of brick/block arrangement, affecting both strength and appearance.
- Stretcher Bond: All bricks laid as stretchers (long side visible). Used for half-brick thick walls.
- Header Bond: All bricks laid as headers (short end visible). Used for curved walls.
- English Bond: Alternating courses of headers and stretchers. Provides maximum strength.
- Flemish Bond: Alternating headers and stretchers in each course. Decorative and strong.
- Rat Trap Bond: Energy-efficient bond where bricks are placed on edge, creating cavity.
- Lay 10-15mm thick mortar bed on the foundation/base
- Start from corners and work inward to maintain alignment
- Place first brick at each corner, checking level and plumb
- Apply mortar to the end of each brick before placing next one
- Maintain consistent joint thickness (10mm typically)
- Check alignment using mason's line after every 3-4 courses
- Maintain proper bond pattern according to design
- Remove excess mortar with trowel before it hardens
- Provide vertical construction joints for long walls (max. 30m)
- Install wall ties for cavity walls as per specifications
Joint finishing affects both appearance and weatherproofing of masonry walls.
- Flush Joint: Mortar filled flush with brick face and compacted
- Recessed Joint: Mortar recessed 3-5mm from brick face
- Weathered Joint: Sloped joint that sheds water downward
- V-Joint: V-shaped depression in mortar joint
- Concave Joint: Curved depression, excellent for water resistance
Finish joints when mortar is thumb-print hard using appropriate jointer tool.
Pro Tip: For accurate masonry work, always build corners first to 4-5 courses height, then fill in between using a mason's line as guide.
Different plaster types offer varying properties for specific applications.
| Type |
Composition |
Best Used For |
Characteristics |
| Cement Plaster |
Cement, sand, water |
Exterior surfaces, wet areas |
Durable, weather-resistant |
| Lime Plaster |
Lime, sand, water |
Heritage buildings, breathable walls |
Flexible, prevents dampness |
| Gypsum Plaster |
Gypsum, water, additives |
Interior walls, ceilings |
Smooth finish, fast setting |
| Mud Plaster |
Mud, straw, water |
Vernacular architecture |
Eco-friendly, thermal properties |
| Application |
Mix Ratio (Cement:Sand) |
Thickness (mm) |
Notes |
| Ceiling Plaster |
1:3 |
6-10 |
Richer mix for better adhesion |
| Internal Wall Base Coat |
1:4 |
8-12 |
Rougher texture for key |
| Internal Wall Finishing Coat |
1:3 |
4-6 |
Finer sand for smooth finish |
| External Wall Base Coat |
1:4 |
12-15 |
With waterproofing compound |
| External Wall Finishing Coat |
1:3 |
6-8 |
Weather resistant finish |
- Plastering Trowel: For applying and spreading plaster
- Float (Wooden/Steel): For leveling and smoothing plaster
- Hawk/Hand Board: For holding plaster while working
- Straight Edge: For leveling plaster and checking flatness
- Plumb Bob: For checking vertical alignment
- Spirit Level: For checking horizontal alignment
- Corner Trowel: For finishing internal and external corners
- Gauging Trowel: For applying plaster in small areas
- Scarifier: For roughening base coats
- Darby: Long flat tool for leveling large areas
- Waterproofing Compounds: For bathrooms, exterior walls
- Plasticizers: Improve workability and reduce cracking
- Fiber Reinforcement: Increases tensile strength, reduces cracking
- Bonding Agents: Improves adhesion to smooth surfaces
- Retarders: Extends working time in hot conditions
- Accelerators: Speeds setting time in cold conditions
- Color Pigments: For decorative colored plaster
Proper surface preparation ensures strong bond between plaster and substrate, preventing future delamination, cracking, and failure. Approximately 70% of plastering defects can be traced back to inadequate surface preparation.
| Surface Type |
Preparation Method |
Special Requirements |
| Brick/Block Wall |
Rake out joints 10-15mm deep, clean surface |
Pre-wet surface before plastering |
| Concrete Surface |
Hack/roughen surface, apply bonding agent |
Ensure free from form oil/release agents |
| Mixed Surfaces |
Install metal mesh/chicken wire at junctions |
Prevent cracking at material interfaces |
| Old Plastered Surface |
Remove loose plaster, clean thoroughly |
Apply bonding agent before new plaster |
- Remove dust, oil, paint, and loose materials from surface
- Repair major defects and fill large holes with appropriate material
- Install necessary reinforcements (corner beads, mesh) at junctions
- Dampen the surface thoroughly before applying plaster
- For smooth surfaces (concrete), apply a spatter dash coat for key
- Ensure all services (electrical, plumbing) are completed
- Fix plaster dots/screeds to establish reference levels
- Confirm that surface is sound, stable, and suitable for plastering
Pre-wetting prevents the substrate from absorbing water from plaster, which would affect setting and strength.
- Spray water evenly across the surface using a hose with spray nozzle
- For highly absorbent surfaces, wet thoroughly 12 hours before plastering
- Wet again lightly 1-2 hours before plastering begins
- Ensure surface is damp but not running with water
- For very hot/dry conditions, wet in stages to maintain dampness
Critical Point: Never apply plaster on dusty, oily, or extremely dry surfaces. Inadequate preparation is the leading cause of plaster failure and delamination.
Guides ensure uniform plaster thickness and level surface across walls and ceilings.
- Mark required plaster thickness at intervals of 1.5-2m
- Install plaster dots or grounds at marked points
- Apply small patches of plaster (dots) at marked positions
- Press in small strips of wood/plastic to required depth
- Check vertical alignment using plumb bob/level
- Create vertical screeds by connecting dots with plaster
- Allow screeds to harden before main plastering begins
- Prepare mortar in appropriate mix ratio (typically 1:4)
- Apply base coat between screeds using trowel
- Press plaster firmly against substrate to ensure good bond
- Level using straight edge (darby) across screeds
- Maintain uniform thickness according to specification
- Allow to reach thumb-print hardness
- Roughen surface with scarifier to create key for finishing coat
- Cure base coat for 24-48 hours before applying finishing coat
- Dampen base coat before applying finishing coat
- Prepare finer mortar mix (1:3 with finer sand)
- Apply thin finishing coat (4-6mm) using trowel
- Smooth with wooden float in circular motion
- Final smoothing with steel float for smooth finish
- Work in small sections to maintain wet edge
- For textured finish, use appropriate tool/technique when plaster is partially set
- Pay special attention to corners and junctions
Proper curing is essential for developing strength and preventing cracks in plaster.
- Begin curing after plaster has initially set (3-6 hours)
- Spray water mist at regular intervals
- For large areas, cover with moist gunny bags
- Continue curing for minimum 7 days for cement plaster
- Protect fresh plaster from direct sunlight, rain, and wind
- Avoid application of any load/pressure during curing period
Pro Tip: When applying base coat, use slightly more pressure than feels natural to ensure proper compaction and adhesion to the substrate. This significantly reduces the risk of delamination.
Used in bathrooms, kitchens, exterior walls, and other areas exposed to water.
- Add integral waterproofing compound to mortar mix (as per manufacturer's instructions)
- Apply waterproofing slurry coat before base coat if required
- Ensure minimum thickness of 15mm for external waterproof plaster
- Apply in two coats with proper curing between coats
- Pay special attention to corners and junctions
- Cure thoroughly for at least 7-10 days
- Test water resistance before finishing or painting
Various decorative finishes can be achieved through different application techniques.
- Pebbledash: Throw small pebbles onto wet plaster and press lightly
- Roughcast: Throw coarse mixture of aggregate, cement and water
- Scraped/Textured: Create pattern with special combs, brushes, or tools
- Stippled: Use stipple brush on partially set plaster for uniform texture
- Smooth: Polish with steel trowel for high-sheen finish
- Sand-Faced: Apply coarse sand on final coat for rustic texture
Spray plastering allows faster application for large areas with consistent quality.
- Prepare surface as for manual plastering
- Use appropriate nozzle and pressure for the material
- Apply in sweeping motion maintaining consistent distance from wall
- Level with straight edge or darby
- Follow with manual finishing as needed
- Clean equipment thoroughly after use
Gypsum plaster provides a smooth finish for interior surfaces with faster setting time.
- Apply bonding agent to smooth substrates
- Mix gypsum plaster according to manufacturer's instructions
- Apply in single coat of 10-13mm thickness
- Level with trowel and straight edge
- Allow initial set (30-40 minutes)
- Smooth and polish with steel trowel
- No water curing required for gypsum plaster
- Allow to dry naturally (typically 5-7 days before painting)
Important: Gypsum plaster should not be used in wet areas or exterior applications. For bathrooms and kitchens, use cement plaster with waterproofing admixture.
| Defect |
Possible Causes |
Prevention/Remedy |
| Vertical Cracks |
Settlement, thermal movement, poor bonding |
Provide expansion joints, proper bonding pattern |
| Efflorescence |
Soluble salts, excess moisture |
Use quality materials, provide DPC, apply silicone sealant |
| Bulging Wall |
Foundation settlement, lateral pressure |
Proper foundation, adequate wall thickness |
| Irregular Coursing |
Poor workmanship, uneven units |
Use mason's line, select uniform bricks |
| Defect |
Possible Causes |
Prevention/Remedy |
| Crazing (Fine Cracks) |
Rapid drying, excessive cement, over troweling |
Proper curing, balanced mix, appropriate finishing |
| Delamination |
Poor surface preparation, insufficient bonding |
Roughen substrate, apply bonding agent, proper pressure |
| Hollow Spots |
Inadequate pressure during application |
Apply firm pressure, work in manageable sections |
| Shrinkage Cracks |
Excessive water in mix, inadequate curing |
Correct water ratio, thorough curing |
- For Cracks: Cut V-groove along crack, clean, dampen, and fill with appropriate mortar
- For Delamination: Remove loose plaster completely, roughen surface, apply bonding agent before new plaster
- For Hollow Areas: Tap to identify extent, cut around perimeter, remove and reapply plaster
- For Efflorescence: Brush off dry deposits, apply diluted acid solution, rinse thoroughly
- For Surface Imperfections: Apply thin finish coat or skim coat after proper preparation
Note: Prevention is always better than cure. Most defects can be avoided through proper material selection, mix proportions, application techniques, and curing procedures.
- Safety Helmet: Protection from falling objects
- Safety Goggles: Protect eyes from dust and splashes
- Dust Mask/Respirator: Prevent inhalation of cement dust
- Work Gloves: Protect hands from cement and sharp objects
- Safety Boots: Provide foot protection on site
- High-visibility Vest: Ensure visibility on busy sites
- Knee Pads: For floor plastering work
- Chemical Hazards: Cement can cause skin burns - wear proper PPE, wash immediately if contact occurs
- Height Work: Use proper scaffolding/platforms, never overreach
- Manual Handling: Use correct lifting techniques, limit load weight
- Tool Safety: Inspect tools before use, maintain properly
- Electrical Safety: Check electrical tools, use RCDs, keep cables away from water
- Dust Control: Use water sprays, ventilation, dust extraction
- Slip Hazards: Clean up spills immediately, maintain clear walkways
- Know location of first aid kits and eye wash stations
- For cement in eyes: Flush with clean water for 15 minutes, seek medical attention
- For cement burns: Wash area with clean water, remove contaminated clothing, seek medical help
- For cuts: Clean wound, apply pressure, seek medical attention if severe
- Know emergency contact numbers and site evacuation procedures
Safety First: Never compromise on safety equipment or procedures. Cement is highly alkaline and can cause serious chemical burns if proper precautions are not taken.
On-Job Training is crucial for masonry and plastering as it bridges the gap between theoretical knowledge and practical application. It allows trainees to develop hands-on skills, adapt to real-world site conditions, and understand the nuances of quality execution under supervision.
- Develops practical skills and muscle memory.
- Exposes trainees to real construction challenges and problem-solving.
- Reinforces safety practices in a live environment.
- Improves speed and efficiency of work.
- Facilitates direct mentorship and feedback from experienced masons/plasterers.
- Structured Curriculum: Follow a defined plan covering all aspects of masonry/plastering.
- Experienced Mentors: Assign skilled and patient supervisors who can guide and correct.
- Hands-on Practice: Provide ample opportunities for practical work, starting with simpler tasks.
- Regular Feedback: Offer constructive criticism and immediate correction of mistakes.
- Safety Integration: Continuously emphasize and enforce safety protocols during all tasks.
- Quality Standards: Train according to industry standards (e.g., IS Codes) and project specifications.
- Tool Proficiency: Ensure trainees are comfortable and efficient with all relevant tools.
- Problem-Solving: Encourage trainees to identify and solve minor issues under supervision.
- Record Keeping: Document trainee progress, skills acquired, and areas for improvement.
- Start Simple: Begin with basic tasks like mixing mortar, laying straight courses, or applying base coats.
- Supervised Progression: Gradually introduce more complex tasks (e.g., corner work, joint finishing, decorative plaster) as proficiency grows.
- Mock-up Practice: Utilize dedicated practice walls or sections for trainees to hone skills before working on live structures.
- Quality Checkpoints: Implement frequent quality checks by mentors at various stages of the trainee's work.
- Tool Maintenance: Teach proper care and maintenance of tools, as well-maintained tools contribute to quality work.
- Material Management: Train on efficient material handling, storage, and minimizing waste.
- Visual Aids: Use diagrams, videos, or physical examples of good and bad workmanship.
- Peer Learning: Encourage experienced workers to share tips and tricks with trainees.
- Certification/Assessment: Conduct periodic assessments to evaluate skill development and ensure competency.
Impact of OJT: High-quality on-job training directly translates to skilled labor, reduced re-work, improved project timelines, and overall better construction quality.
Masonry and plastering are fundamental skills in construction that directly impact both structural integrity and aesthetic appeal. Proper techniques ensure long-lasting and defect-free construction, while reducing maintenance costs over the building's lifespan.
Remember that quality in masonry and plastering comes from careful material selection, proper preparation, accurate execution, and diligent curing. Each step builds upon the previous one, making attention to detail essential throughout the process.
By following the guidelines in this training module, construction professionals can deliver high-quality masonry and plaster work that meets industry standards and client expectations.
Key Takeaway: Master the fundamentals, prioritize quality, and continuously learn to excel in masonry and plastering.