Chapter 10 of 16

Masonry and Plaster Work

In the CWC AM Civil syllabus under Building Materials · 3 parts

Brick Masonry · Stone Masonry · Plastering, Pointing & Finishing Works

CIVILGYAN TEST SERIES · civilgyantests.com — free study notes for civil engineering exams

📑 Contents (30 sections)

Part 1 of 3

Brick Masonry

Last reviewed 16 Sept 2026 · 11 min read

Terms in brickwork

Term	Meaning
Stretcher	Brick laid with its length along the face of the wall (the longer narrow face — the stretcher face — exposed)
Header	Brick laid with its length across the wall (the end face exposed)
Bed	Lower surface of the brick when laid; bed joint — horizontal mortar joint
Frog	Depression on one bed face — laid upwards and filled with mortar
Lap	Horizontal distance by which one brick projects beyond a vertical joint in the course below (commonly one-quarter brick in standard bonds)
Perpend	Vertical joint on the face of a wall — perpends in alternate courses should line up vertically
Closer	A piece of brick cut lengthwise to complete a course or to maintain bond: queen closer (half the width, cut along the length — full length, half width), king closer (one corner cut off diagonally, leaving half header and half stretcher faces), bevelled closer, mitred closer
Bat	A piece of brick cut across its width — half bat, three-quarter bat, bevelled bat
Quoin	External corner of a wall; quoin header/stretcher — brick at the corner
Racking back	Stepping back each course at the end of a wall section being built, so that later work can be bonded in
Toothing	Leaving alternate courses projecting at the end of a wall for future bonding
Squint quoin	Corner that is not a right angle
Course	One horizontal layer of bricks

Rules for bonding

Bond is the arrangement of bricks in successive courses so that vertical joints do not coincide, distributing loads and binding the wall together.

Bricks should be of uniform size; length about twice the width plus one joint.
Lap should be at least one-quarter brick along the length of the wall and half a brick across the thickness.
No continuous vertical joints in the face or within the thickness.
Stretchers are used mainly on the faces; the hearting should be filled with headers as far as possible.
Minimum use of bats; closers are placed next to quoin headers to develop lap.
Vertical joints in alternate courses should be in the same vertical line (perpends).
Each alternate header should be centrally placed over the stretcher below (in appropriate bonds).

Types of bonds

Bond	Arrangement	Use / remarks
Stretcher (running) bond	All bricks laid as stretchers, with half-brick lap in successive courses	Half-brick thick walls — partitions, cavity wall leaves, facing; not for thicker load-bearing walls (no bonding across thickness)
Header bond	All bricks laid as headers with half-width lap (three-quarter bats at quoins in alternate courses)	One-brick thick walls, curved walls (small radius), footings (for load distribution); less attractive for long walls
English bond	Alternate courses of headers and stretchers; a queen closer placed next to the quoin header in each header course; headers centred over stretchers	Strongest bond — load-bearing walls, piers; no continuous vertical joints
Flemish bond	Headers and stretchers alternate in the same course; each header centred over a stretcher of the course below; queen closers next to quoin headers in alternate courses	Better appearance; double Flemish (Flemish on both faces) and single Flemish (Flemish on face, English backing)
English garden wall bond	One course of headers to three to five courses of stretchers	Garden and compound walls (economical, attractive)
Flemish garden wall bond	In each course, one header after three to five stretchers	Garden and boundary walls
Facing bond	Header courses at intervals tying a facing of stretchers to backing	When facing and backing bricks differ in thickness
Raking bond	Bricks laid at an angle in the interior of thick walls — diagonal bond (45° in each direction in alternate courses) and herring-bone bond (V-pattern)	Increases longitudinal strength of thick walls; herring-bone for paving and decorative work
Dutch bond	Modified English bond with three-quarter bats at quoins and no queen closers	Strong corners
Zig-zag bond	Similar to herring-bone with zig-zag pattern	Brick paving, ornamental work
Stack bond	Bricks stacked with continuous vertical joints	Non-load-bearing decorative work (needs reinforcement)

English bond versus Flemish bond

English bond	Flemish bond
Headers and stretchers in alternate courses	Headers and stretchers alternate in every course
Stronger (fewer bats, better bonding through thickness) — preferred for load-bearing walls thicker than one brick	Somewhat weaker for walls thicker than 1½ bricks; uses more brickbats
Less attractive (plain appearance)	Better appearance on the face
Easier to construct; less skilled labour	Needs more skill and care
Economical	Slightly less economical (more cut bricks), but bats can use broken bricks

Construction practice and precautions

Use good-quality bricks (well burnt, uniform); soak bricks in water before use (to prevent absorption of water from mortar) but lay them surface-dry.
Lay bricks with frogs upward on a full bed of mortar; fill all vertical joints ("buttering").
Keep mortar joints uniform — commonly about 10 mm.
Build walls plumb and courses level using a mason's line, spirit level and plumb bob; check with a straight edge.
Raise the wall uniformly along its length; limit the height built in a day (commonly about 1 m or less) to allow mortar to gain strength; use racking back rather than toothing at junctions where possible.
Break joints according to the bond; use closers at quoins; avoid excessive use of bats.
Cure brickwork by keeping it moist (commonly at least 7 days for cement mortar).
Rake joints (about 10–12 mm deep) while mortar is green if the wall is to be plastered or pointed.
Provide holdfasts for door and window frames, and bond walls at junctions.
Protect fresh work from rain, hot sun and frost; do not load newly built walls prematurely.
Leave scaffolding holes only as permitted and fill them afterwards.

Reinforced brick masonry and brick nogging

Reinforced brick masonry (RBM) — steel bars or hoop iron embedded in mortar joints or grouted cores to resist tension, shear and seismic forces — lintels, slabs (reinforced brick concrete), walls in earthquake zones.
Half-brick walls (partitions) are often strengthened with hoop iron or reinforcement in every third or fourth course.
Brick nogging — brickwork filling a framework of timber or concrete posts and rails (panel walls).
Earthquake-resistant masonry — horizontal RCC bands (plinth, lintel, roof bands) and vertical reinforcement at corners and junctions as per IS 4326.

Strength of brickwork

The strength of brick masonry depends on:

Compressive strength of bricks and mortar grade (masonry strength is less than brick strength).
Workmanship — filling of joints, joint thickness (thicker joints reduce strength), wetting of bricks, bond.
Slenderness ratio of walls and columns — effective height (or length) ÷ effective thickness; higher slenderness reduces permissible stress (stress reduction factor).
Eccentricity of loading.
Shape and size of units.

IS 1905 (Code of practice for structural use of unreinforced masonry) gives basic compressive stresses for masonry based on unit strength and mortar type, stress reduction factors for slenderness and eccentricity, area reduction factors, limits on slenderness ratio (commonly up to about 27 for walls in cement or cement–lime mortar), and minimum wall thicknesses.

FormulaSlenderness ratio

S R = \frac{h _{e f}}{t _{e f}}

$h_{e f}$ = effective height (depends on end restraints — e.g. about 0.75 × clear height when floors restrain the wall at top and bottom); $t_{e f}$ = effective thickness.

Defects in brick masonry

Defect	Cause / remedy
Efflorescence	Soluble salts in bricks or mortar brought to the surface by moisture — use good bricks, prevent dampness, brush off salts
Sulphate attack	Sulphates from bricks or soil react with cement mortar (tricalcium aluminate) causing expansion, cracking and disintegration of joints — use sulphate-resisting cement, low-sulphate bricks, keep walls dry
Cracking	Differential settlement of foundations, thermal and moisture movements, overloading, shrinkage of mortar, corrosion of embedded iron — provide expansion joints, good foundations, bands
Crystallisation of salts	Salts crystallising within pores cause spalling
Dampness	Absence of DPC, porous bricks, defective pointing — damp-proofing measures
Bulging	Lack of bonding or through ties, eccentric loads — proper bonding, ties

Quantity of bricks and mortar

FormulaBricks and mortar per cubic metre

Modular bricks (190 × 90 × 90 mm; nominal 200 × 100 × 100 mm with 10 mm joints):

Number of bricks $= \frac{1}{0.2 \times 0.1 \times 0.1} = 500$ per m³
Volume of bricks $= 500 \times 0.19 \times 0.09 \times 0.09 = 0.77$ m³ → wet mortar ≈ 0.23 m³, commonly increased to about 0.25–0.30 m³ to allow for frog filling and wastage

Conventional bricks (about 230 × 110 × 70 mm; nominal 240 × 120 × 80 mm): about 520 bricks per m³ (commonly taken as about 500 in practice after allowances), with a similar mortar requirement.

Dry volume of mortar ingredients ≈ 1.27–1.33 × wet volume.

Worked examples

Worked ExampleExample 1 — bricks and mortar for a wall

A wall 10 m long and 3 m high is built in one-brick thickness with modular bricks (200 mm nominal thickness) in 1 : 6 cement mortar. Find the number of bricks, cement bags and sand (use 0.25 m³ wet mortar per m³ and a dry factor of 1.30; ignore wastage).

Solution. Volume $= 10 \times 3 \times 0.20 = 6$ m³ → bricks $= 6 \times 500 = 3000$ Wet mortar $= 6 \times 0.25 = 1.5$ m³ → dry $= 1.95$ m³ Cement $= 1.95/7 = 0.279$ m³ → $0.279/0.0347 = 8.0 bags$ ; sand $= 0.279 \times 6 = 1.67 m^{3}$

Worked ExampleExample 2 — slenderness ratio

A 200 mm thick load-bearing brick wall has a clear height of 3.0 m and is restrained by RCC slabs at top and bottom (effective height = 0.75 × height). Find its slenderness ratio.

Solution. $h_{e f} = 0.75 \times 3.0 = 2.25$ m → $S R = \frac{2.25}{0.20} = 11.25$ (well within the usual limit)

Worked ExampleExample 3 — closers

Why is a queen closer placed next to the quoin header in English bond?

Solution. It shifts the stretchers of the next course by a quarter brick relative to the headers, giving the required lap of one-quarter brick and preventing continuous vertical joints at the corner.

Frequently tested points

Stretcher — length along face; header — length across wall; lap ≥ ¼ brick; perpends aligned in alternate courses.
Queen closer — half width (cut lengthwise); king closer — one corner cut; bats cut across width.
Racking back preferred over toothing.
Stretcher bond — half-brick walls; header bond — curved walls and footings; English bond — alternate header and stretcher courses, strongest; Flemish bond — headers and stretchers alternate in each course, better appearance.
Garden wall bonds: 1 header course (or header) per 3–5 stretchers.
Raking bond (diagonal, herring-bone) for thick walls; stack bond non-load-bearing.
Practice: soak bricks, frog up, 10 mm joints, raise uniformly (≈ 1 m/day), cure ≥ 7 days, rake joints for plaster.
Half-brick partitions with hoop iron every few courses; RCC bands for earthquake resistance (IS 4326).
IS 1905: masonry strength depends on unit strength, mortar, slenderness and eccentricity; slenderness limit about 27.
Defects: efflorescence, sulphate attack, cracking, dampness.
Modular bricks: 500 per m³; wet mortar about 0.25–0.30 m³ per m³.

Common MistakeCommon mistakes

Using stretcher bond for a one-brick-thick load-bearing wall (no bonding across thickness).
Laying bricks dry, which weakens mortar bond.
Confusing queen closers (half width) with half bats (half length).

Revision SummaryChapter summary

Brickwork terms describe unit positions, joints, cut bricks (closers and bats) and construction details such as racking back.
Bonding rules ensure lap and avoid continuous vertical joints.
Stretcher, header, English, Flemish, garden wall, raking and other bonds suit different wall thicknesses and appearances; English bond is strongest, Flemish more attractive.
Good practice — soaked bricks, full joints, uniform raising, curing — and reinforcement or RCC bands improve performance; IS 1905 governs design strength.
Defects such as efflorescence, sulphate attack and cracking must be prevented; brick and mortar quantities follow standard per-m³ values.

Part 2 of 3

Stone Masonry

Last reviewed 16 Sept 2026 · 10 min read

Masonry

Masonry is construction with individual units (stones, bricks, blocks) laid and bound together with mortar. Stone masonry is used for foundations, walls, retaining walls, piers, abutments, dams and architectural facings where good stone is locally available.

Technical terms

Term	Meaning
Course	A horizontal layer of stones or bricks
Bed	The surface of a stone perpendicular to the line of pressure (its top/bottom in a wall); bed joint — horizontal mortar joint
Joint (cross/vertical joint, perpend)	Mortar joint perpendicular to the bed joints
Header	A stone (or brick) laid with its length across the wall (perpendicular to the face)
Stretcher	A stone laid with its length along the face of the wall
Through stone (bond stone)	A stone extending through the full thickness of the wall — ties both faces together
Quoins	Stones forming the external corners of walls, usually larger and dressed
Corbel	A stone projecting from the wall face to support a beam, cornice or other load
Cornice	A projecting ornamental course at the top of a wall (also sheds rainwater)
Coping	Covering course on the top of a wall/parapet to protect it from rain; weathered (sloped) and throated
String course	Horizontal course projecting from the wall face along its length (at floor or sill level) — appearance and weather protection
Plinth course	The top course of the plinth
Jambs	Vertical sides of a door or window opening
Reveal	The exposed part of the jamb between the frame and the wall face
Sill	Horizontal member at the bottom of a window opening (weathered to shed water)
Lintel	Horizontal member spanning over an opening
Hearting	The interior filling of a wall between the face and back stones
Spalls (pinnings)	Small chips of stone used to fill interstices in rubble masonry
Weathering	Sloping top surface of projecting courses to shed rainwater
Throating	A groove on the underside of a projecting course or sill so that water drips off and does not run back to the wall
Blocking course	Course placed above a cornice to weigh it down
Parapet	Low wall at the edge of a roof, terrace or bridge
Template	A stone/concrete block placed under a beam to distribute load on the wall
Arris	The sharp edge where two surfaces of a stone meet

Classification of stone masonry

1. Rubble masonry

Stones of irregular sizes and shapes (as obtained from the quarry or roughly dressed) laid in mortar. Economical but lower strength than ashlar.

Type	Description	Use
Uncoursed random rubble	Stones of irregular shape and size laid without regular courses; interstices filled with spalls and mortar; larger stones at corners and jambs; through stones at intervals	Walls of low-height buildings, compound walls, godowns, foundations
Coursed random rubble	Stones of irregular shapes brought to level courses at intervals (e.g. every 30–45 cm)	Residential buildings, public works — better than uncoursed
Uncoursed squared rubble	Stones roughly squared (hammer dressed) laid without courses	Ordinary buildings
Coursed squared rubble	Squared stones in courses of varying height	Better class walls
Regular coursed rubble	Squared stones with uniform course heights	Public buildings, residential buildings, piers and abutments of ordinary bridges
Polygonal rubble	Stones hammer dressed to polygonal (irregular polygon) faces fitting together	Decorative walls
Flint rubble	Flints (nodules of silica) as facing, with lacing courses of brick or stone	Regions where flint is available
Dry rubble masonry	Rubble laid without mortar, carefully packed with spalls	Retaining walls on hill roads, pitching, compound walls, revetments (allows drainage)

2. Ashlar masonry

Stones finely dressed to regular shapes and sizes, laid in courses with fine, thin joints (often about 3–6 mm). Strong, attractive, but costly.

Type	Face finish
Ashlar fine	Every stone finely dressed on all sides; very thin joints — superior facing, monuments, important buildings
Ashlar rough tooled	Bed and side joints finely dressed; exposed face rough tooled (with a margin chisel-drafted)
Ashlar rock (quarry) faced	Exposed face left rough as from the quarry, with chisel-drafted margins — rustic appearance, massive look
Ashlar chamfered	Edges of the exposed face chamfered (bevelled) to form grooves at joints — used for plinths, quoins
Ashlar facing	Ashlar stones used as facing with rubble or brick backing
Block-in-course	Intermediate between rubble and ashlar — stones squared and dressed, courses of uniform height (often 20–30 cm), joints thicker than in ashlar — heavy works (bridges, docks, retaining walls)

3. Composite masonry

A combination of different masonry types or materials — e.g. stone facing with brick backing, stone and concrete — for economy and appearance while using cheaper backing.

General principles of construction

Use hard, durable, well-seasoned stones free from defects; wet stones before laying to avoid absorbing water from mortar.
Lay stones on their natural bed (bed perpendicular to the pressure); in arches the bed is radial; in cornices vertical.
Provide through (bond) stones at regular intervals (commonly about 1.5–2 m apart in each course and at every course or alternate courses in height) or headers overlapping from both faces where full-length stones are not available.
Break (stagger) vertical joints in successive courses — avoid continuous vertical joints.
Face stones should tail well into the wall (length into the wall at least equal to height); hearting solidly filled with stones, spalls and mortar — no hollow spaces.
Use the largest stones in the lower courses, at corners (quoins) and jambs.
Use mortar of suitable proportion (commonly cement mortar 1 : 6 for rubble work); joints fully filled.
Raise walls uniformly throughout their length — limit the height raised in a day; stagger (rack back) junctions for later work.
Keep walls plumb and courses level; check with plumb bob and spirit level.
Cure masonry by keeping it wet (commonly at least 7 days for cement mortar).
Protect fresh work from rain, frost and hot sun.
Provide weathering and throating on projecting courses; coping on parapets.

Tools used in stone masonry

Trowel, spirit level, plumb bob and plumb rule, straight edge, square, mason's line, mallet and hammers (spalling hammer, club hammer), chisels (pitching tool, punch, point, claw tool, drafting chisel, boaster), scutch, gauges and templates.

Joints in stonework

Joint	Description / use
Butt (square) joint	Plain joint — ordinary work
Rebated (lapped) joint	Stones with rebates overlapping — copings, gable walls
Tongue and groove (joggle) joint	Tongue fits into groove — prevents sliding (steps, copings, lintels)
Cramped joint	Metal cramps (copper, gunmetal, stainless steel) set in mortises across joints — copings, cornices, parapets
Dowelled joint	Dowels (metal/slate) fitted into holes in adjacent stones — prevents sliding
Plugged joint	Dovetail recesses filled with molten lead/mortar
Joggled joint	Projection fits into recess — arches, flat arches, heavy stonework

Stone masonry compared with brick masonry

Stone masonry	Brick masonry
Higher strength and durability; resists weathering	Adequate strength; less durable in severe exposure
Heavier; thicker walls needed (commonly at least about 350–400 mm)	Thinner walls possible (half-brick, one-brick)
Greater skill and time for dressing and laying	Easier and faster; uniform units
Economical only where stone is locally available	Generally economical and widely available
Better appearance (natural stone), less maintenance	Needs plaster/pointing for weather protection in many cases
Poor thermal insulation (dense stone); damp penetration possible through joints	Better thermal insulation than dense stone
Difficult to make openings, alterations	Easier alterations and fixing
Suitable for dams, retaining walls, piers, foundations, monumental buildings	Suitable for most building walls

Quantity estimation

Stone masonry is measured in cubic metres (m³). For rubble masonry, quantities of stone and mortar per m³ of masonry are taken from standard data of the relevant schedule of rates — for rough estimates, rubble masonry is often assumed to need about 0.3–0.35 m³ of wet mortar per m³ of masonry, with the remainder stone (allowing for voids in stacked stone).

Worked examples

Worked ExampleExample 1 — wall volume

A random rubble masonry wall is 10 m long, 3 m high and 450 mm thick. Find its volume.

Solution. $V = 10 \times 3 \times 0.45 = 13.5 m^{3}$

Worked ExampleExample 2 — mortar materials

For the wall in Example 1, assuming 0.34 m³ of wet cement mortar (1 : 6) per m³ of masonry and a dry volume factor of 1.30, find the cement (bags) and sand required.

Solution. Wet mortar $= 13.5 \times 0.34 = 4.59$ m³ → dry volume $= 4.59 \times 1.30 = 5.97$ m³ Cement $= 5.97/7 = 0.853$ m³ → $0.853/0.0347 = 24.6 bags$ Sand $= 0.853 \times 6 = 5.12 m^{3}$

Worked ExampleExample 3 — through stones

A 12 m long coursed rubble wall has through stones at 1.5 m centres in every course. How many through stones per course are needed?

Solution. $12/1.5 = 8$ spaces → about 8–9 through stones per course (including one near each end/corner)

Frequently tested points

Header — length across wall; stretcher — length along face; through (bond) stone — full thickness.
Quoins at corners; corbel projects to support loads; coping on top of walls; throating drips water off.
Hearting fills the interior; spalls fill gaps in rubble.
Rubble masonry: uncoursed random, coursed random, squared rubble (uncoursed/coursed/regular coursed), polygonal, flint, dry rubble (retaining walls on hill roads).
Ashlar masonry: finely dressed stones, thin joints — ashlar fine, rough tooled, rock/quarry faced, chamfered; block-in-course intermediate.
Principles: natural bed, through stones at intervals, staggered joints, solid hearting, largest stones at bottom and corners, uniform raising, curing.
Joints: rebated, tongue and groove, cramped (metal cramps), dowelled, joggled.
Stone masonry — stronger, more durable, heavier, thicker walls, more skill; brick masonry — faster, thinner walls, easier alterations.

Common MistakeCommon mistakes

Leaving continuous vertical joints or hollow hearting in rubble walls.
Omitting through stones in thick walls, causing the two faces to separate.
Laying stratified stones with the natural bed parallel to the load direction.

Revision SummaryChapter summary

Masonry terms describe units, joints, courses and architectural elements such as quoins, corbels, cornices, copings, sills and lintels.
Rubble masonry (random, squared, polygonal, flint, dry) is economical; ashlar masonry with finely dressed stones is strong and attractive; block-in-course lies between.
Good construction lays stones on the natural bed, uses through stones, staggers joints, fills hearting solidly and cures the work.
Special joints (rebated, tongue and groove, cramped, dowelled, joggled) resist sliding and separation.
Stone masonry is stronger and more durable but heavier and slower than brick masonry; quantities are measured in cubic metres with mortar estimated from standard data.

Part 3 of 3

Plastering, Pointing & Finishing Works

Last reviewed 16 Sept 2026 · 10 min read

Plastering

Plastering is the application of a thin layer of mortar (plaster) over walls, ceilings and other surfaces.

Objects

Protect masonry from rain, weathering and atmospheric agents.
Provide a smooth, even, hygienic surface for paint, whitewash or other finishes.
Conceal defective workmanship and inferior materials.
Improve appearance (decorative textures).
Seal joints and reduce dampness penetration; improve fire resistance and sound insulation to some extent.

Plaster mortars

Mortar	Features / use
Cement plaster	Cement and sand, commonly 1 : 3 to 1 : 6; strong, durable, water resistant — external walls, damp areas, internal walls; richer mixes (1 : 3, 1 : 4) for ceilings and exposed surfaces
Lime plaster	Fat or hydraulic lime with sand/surkhi; good workability, flexible, breathable — heritage and interior work; slow hardening
Cement–lime (composite) plaster	Improved workability and water retention with cement strength; less cracking
Gypsum plaster	Ready-mix gypsum — smooth interior finish, quick setting, no water curing; not for external/wet areas
Mud plaster	Clay, sand, straw/cow dung — low-cost rural buildings; needs protective wash

Special plasters and finishes

Plaster	Description
Stucco plaster	Decorative plaster for external (and internal) surfaces, commonly applied in three coats (scratch, fine and finishing coats) — imitates stone
Sand-faced plaster	Final coat finished by sprinkling or rubbing sand to give a uniform sandy texture
Rough cast (spatter dash)	Mortar containing coarse aggregate thrown onto the wall — rough, weather resistant external finish
Pebble dash	Pebbles or crushed stone thrown into the fresh plaster and pressed in
Textured / scraped / combed finishes	Patterns formed in the final coat
Waterproof plaster	Cement plaster with waterproofing admixtures
Acoustic plaster	Porous plaster (e.g. with gypsum and lightweight aggregates) — sound absorption
Barium plaster	Contains barium sulphate — X-ray shielding walls in hospitals
Keene's cement	Hard, white, polished finish obtained from burnt gypsum with alum — fine interior finish
Parian and Martin's cements	Hard gypsum-based finishing plasters
Scagliola	Imitation marble finish made from gypsum/Keene's cement with glue and colouring
Granite/marble chips plaster, grit plaster	Exposed aggregate decorative finishes

Thickness and number of coats

Surface	Typical thickness
Internal brick walls	12 mm (single coat)
External walls	15–20 mm (often in two coats; e.g. 12–15 mm base coat + about 6 mm finishing coat)
Ceilings (RCC)	6–10 mm
Rough stone/rubble masonry	Up to about 20–25 mm or more to fill irregularities

One-coat plaster — common for internal walls.
Two-coat plaster — first (rendering) coat to fill irregularities, second (finishing) coat for a smooth surface — external walls.
Three-coat plaster — rendering, floating and finishing coats — stucco and high-quality work.

Method of plastering

Preparation of the surface
- Rake out mortar joints of masonry to a depth of about 10–12 mm (while mortar is green or by raking later) to provide a key.
- Remove dust, loose mortar, oil and efflorescence; roughen smooth concrete surfaces (hacking) or apply a bonding agent.
- Wet the surface thoroughly (so it does not absorb water from the plaster), but without standing water.
- Fix chicken wire mesh (galvanised welded mesh) across junctions of different materials (e.g. RCC columns/beams and brick masonry) and over service chases to prevent cracks.
Fixing grounds (screeds/dots) — small patches (dots) of plaster at intervals, made plumb and level, joined into vertical strips (screeds) to act as thickness guides.
Application — the base coat is thrown/dashed onto the wall with a trowel and pressed in; filled between screeds.
Levelling — a straight edge (aluminium/wooden) is worked over the screeds to remove excess and level the surface; low spots filled.
Floating — surface rubbed with a wooden float to compact and smooth.
Finishing coat (where specified) — applied after the base coat has partially set; finished with a steel trowel (smooth) or other tool for texture.
Curing — keep plaster moist for at least 7 days (cement plaster), starting after initial set; protect from hot sun and drying wind.
Work sequence — plaster the ceiling first, then walls, from top downwards; avoid joints in the middle of a panel (end at corners or bands).

Finishing treatments

Neeru (lime putty) finish — a thin coat of well-matured lime putty trowelled smooth over lime/cement plaster (traditional).
Punning — thin coat of plaster of Paris applied over cement plaster for a very smooth white surface.
Wall putty — white cement–polymer based putty applied in thin coats and sanded — smooth base for paints.

Defects in plastering

Defect	Cause
Cracking and crazing	Rich mortar and excessive shrinkage, rapid drying (no curing), thermal movement, structural movement, junctions of different materials without mesh, thick single coats
Blistering	Expansion of unslaked lime particles in lime plaster; also moisture beneath finish coats
Popping	Small conical pits formed as particles of unslaked lime or other expansive matter expand and blow out
Efflorescence	Soluble salts in bricks, sand or water brought to the surface by moisture
Peeling / flaking / hollow (drummy) sound	Poor bond — dry or dusty background, smooth surface without key, joints not raked, plaster applied too thick or on a surface that absorbed its water
Softness / powdering	Poor-quality or insufficient binder, excess sand, inadequate curing, dampness
Rust stains	Corroding iron embedded in or behind plaster
Uneven surface	Poor workmanship, lack of screeds, improper floating
Dampness patches	Leakage, rising damp, porous plaster
Grinning	Joints of masonry visible through thin plaster due to differential suction

Pointing

Pointing is the finishing of mortar joints in exposed masonry (without plaster) by raking out the joints and filling them with richer mortar in a desired shape.

Objects

Make joints weather-tight and durable (prevent entry of water).
Improve appearance by emphasising the joint pattern.
Economical alternative to plastering for good-quality facing brickwork or stonework.

Procedure

Rake out joints to a depth of about 10–20 mm (commonly about 12–15 mm) while mortar is green or with a raking tool.
Clean joints of dust and loose particles; wet the surface.
Fill joints with rich mortar — commonly 1 : 2 or 1 : 3 cement–sand (lime mortar for lime masonry) — and press it well in.
Finish to the required profile with a pointing tool.
Cure for about a week.

Types of pointing

Type	Profile / description	Remarks
Flush pointing	Mortar finished flush with the face of the masonry	Simple, durable (no ledges to hold water), does not emphasise joints much
Recessed pointing	Mortar pressed back about 5 mm or more behind the face, with vertical face	Good appearance for good-quality bricks/stones; can collect water
Struck (weather struck) pointing	Face of the joint inclined — the upper edge pressed in (about 10 mm) and the lower edge flush with the face, so the joint slopes outward	Sheds rainwater easily — suitable for exposed walls
Weathered pointing	Mortar formed into a V-shaped projection on the joint	Decorative; projection sheds water
Rubbed, keyed or grooved pointing	Mortar flush, with a groove formed along the centre of the joint	Good appearance
Tuck pointing	Joint filled flush and a narrow groove (about 5 mm × 3 mm) cut in the centre, which is filled ("tucked") with white cement putty projecting slightly	Decorative; durability depends on the projecting fillet
V-grooved pointing	V-shaped groove formed in a flush joint	Decorative
Beaded pointing	Convex (bead) profile formed with a beading tool	Attractive, but the bead is easily damaged
Vee (V) pointing / raised pointing	Projecting joint profiles	Decorative

(Terminology of pointing profiles varies somewhat between references; for exposed work the finished joint should drain rainwater outward rather than trap it.)

Other wall finishes

Cladding — natural stone slabs (granite, sandstone), ceramic and vitrified tiles, terracotta panels, aluminium composite panels, glass — fixed with mortar/adhesive or dry mechanical fixing.
Wall tiling in kitchens, toilets and hospitals.
Dry lining — gypsum boards on frames.
Textured coatings, exposed brick or concrete with sealants, wallpapers and panelling (interiors).

Quantity of plaster mortar

FormulaPlaster mortar quantity

Wet volume = area \times thickness (+ allowance for filling joints and unevenness, commonly about 20-30%)

Dry volume \approx 1.27 to 1.33 \times wet volume

Cement and sand follow from the mix proportion; one bag of cement ≈ 0.0347 m³.

Worked examples

Worked ExampleExample 1 — cement plaster materials

Find the cement and sand for 100 m² of 12 mm thick cement plaster 1 : 6. Allow 20% extra for joints and unevenness and use a dry volume factor of 1.27.

Solution. Wet volume $= 100 \times 0.012 = 1.2$ m³ → with 20% $= 1.44$ m³ Dry volume $= 1.44 \times 1.27 = 1.83$ m³ Cement $= 1.83/7 = 0.261$ m³ → $0.261/0.0347 = 7.5 bags$ Sand $= 0.261 \times 6 = 1.57 m^{3}$

Worked ExampleExample 2 — thickness selection

Suggest plaster thickness for (a) an RCC ceiling, (b) internal brick walls, (c) external brick walls in a rainy area.

Solution. (a) about 6–10 mm; (b) about 12 mm; (c) about 18–20 mm in two coats with a rich waterproofed mix and good curing.

Worked ExampleExample 3 — diagnosing a defect

New lime plaster shows small conical pits with a white core a few weeks after application. Identify the defect and its prevention.

Solution. Popping (blowing) caused by unslaked lime particles expanding. Prevent by using thoroughly slaked and matured lime putty and screening out lumps.

Frequently tested points

Plastering protects masonry and gives a smooth surface; cement plaster 1 : 3–1 : 6.
Thickness: internal 12 mm; external 15–20 mm; ceiling 6–10 mm.
Preparation: rake joints 10–12 mm, clean, wet; chicken mesh at RCC–masonry junctions.
Screeds (dots) guide thickness; straight edge levelling; float finish; ceiling first, top downwards.
Cure cement plaster ≥ 7 days; gypsum plaster needs no water curing.
Neeru — lime putty finish; punning — POP; wall putty — base for paint.
Special plasters: stucco (3 coats), rough cast (thrown coarse mix), pebble dash (pebbles thrown into fresh plaster), barium plaster (X-ray), Keene's cement (hard white finish), scagliola (imitation marble).
Defects: cracking (shrinkage, no curing), blistering and popping (unslaked lime), efflorescence (salts), peeling (poor bond), rust stains.
Pointing: rake 10–20 mm, fill with 1 : 2–1 : 3 mortar; flush, recessed, struck (upper edge pressed in — sheds water), weathered (V projection), keyed/grooved, tuck (white cement fillet), V-grooved, beaded.
Plaster quantity: area × thickness + 20–30%; dry factor ~1.27–1.33.

Common MistakeCommon mistakes

Plastering a dry, dusty wall without raking joints (causes hollow, peeling plaster).
Skipping mesh at junctions of concrete and brickwork (cracks along junctions).
Applying a thick single coat in hot sun without curing.

Revision SummaryChapter summary

Plastering protects and finishes surfaces using cement, lime, composite, gypsum or mud mortars and special decorative or functional plasters.
Thickness and number of coats depend on surface and exposure.
Good plastering needs surface preparation, screeds, proper application, levelling, finishing, mesh at junctions and curing.
Defects such as cracking, blistering, popping, efflorescence and peeling arise from materials, background and workmanship.
Pointing finishes exposed masonry joints in profiles such as flush, recessed, weather struck, tuck and beaded; quantities follow area, thickness and dry volume factors.

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