RBSE SS Voc Construction cheat sheet

Brick class: first class = burnt in kilns, sharp edges, water absorption < 20% by weight, compressive strength >= 10.5 N/mm²; second class absorption 20-22%; third class absorption 22-25%.

Cement setting: initial set >= 30 min, final set <= 600 min (ordinary Portland); soundness by Le Chatelier or autoclave; fineness by Blaine (specific surface, m²/kg).

Concrete grade M20 means characteristic cube strength 20 N/mm² at 28 days; target mean strength = fck + 1.65 × standard deviation.

Water-cement ratio rule: lower w/c gives higher strength and lower permeability; 0.4-0.6 typical; excess water causes bleeding, segregation, and shrinkage cracks.

Aggregate: coarse aggregate nominal size 20 mm for normal RCC, 40 mm for mass concrete; fine aggregate grading zone I-IV per IS 383; silt content in sand should be < 3% by mass.

Steel: Fe415 and Fe500 denote yield strength in N/mm²; HYSD bars have higher yield and better bond than mild steel Fe250; elongation for Fe415 >= 14.5%.

Timber: moisture content should be 10-12% before use; seasoning reduces shrinkage, warping, and decay; density and grain direction affect strength (strongest parallel to grain).

Mortar and plaster: 1:3 cement-sand for structural mortar, 1:4 to 1:6 for plaster; lime mortar has lower strength but better workability and elasticity.

Foundation depth rule: minimum 0.9-1.0 m below natural ground level or below frost line, whichever is deeper; bearing capacity from soil test governs footing size.

Brick masonry bonds: English bond alternates header and stretcher courses (strongest); Flemish bond alternates header and stretcher in each course; stretcher bond used for half-brick walls.

DPC (damp-proof course): 1:2 cement mortar with waterproofing compound or bitumen felt, laid at plinth level, min 40-50 mm thick, continuous across walls.

Concrete cover: 40 mm for footings, 25-30 mm for columns and beams, 15-20 mm for slabs (mild exposure); cover protects reinforcement from corrosion and fire.

Staircase: rise 150-190 mm, tread 250-300 mm, going plus twice rise ≈ 600-640 mm; headroom min 2.1 m; width of residential stair min 0.9 m.

Lintel and chajja: lintel spans openings and carries masonry above; chajja (sunshade) projects 0.6-1.0 m with a drip groove to prevent water return.

Roof slope: flat RCC roof 1:50 to 1:100 for drainage; pitched roof slope depends on covering (e.g., 1:3 for tiles, 1:5 for corrugated sheets).

Plastering: 12-15 mm thick single coat, 20 mm two-coat; mortar 1:4 to 1:6; curing at least 7 days; check with 2 m straight edge for evenness.

Scale notation: 1:100 means 1 unit on drawing equals 100 units on ground; 1:50 is more detailed; site plans often 1:500 or 1:1000.

Line types: continuous thick = visible outlines; dashed = hidden edges; chain/dash-dot = centre lines and grid lines; thin continuous = dimension and projection lines.

Dimensioning: dimension line with arrowheads or oblique strokes, extension lines from the object, numerals above the line; all dimensions in millimetres unless stated otherwise.

Plan, elevation, section: plan is a horizontal cut view from above; elevation is front view; section shows internal details cut by a plane, often with hatching for materials.

Grid lines labelled A, B, C horizontally and 1, 2, 3 vertically; column centre lines intersect at grid intersections; structural drawings use grid references.

Symbols: door swing arc, window with glazing lines, north arrow on site plan, section mark with letter and arrow direction, level mark with inverted triangle and RL.

Working drawing checklist: setting-out plan, foundation plan, structural framing plan, architectural floor plans, elevations, sections, door/window schedule, and bar bending schedule.

Bar bending schedule (BBS): lists bar mark, diameter, shape, number, cutting length, and weight; weight per metre = d²/162 kg/m for steel (d in mm).

Types of estimate: approximate (plinth area, cubic content, unit rate), detailed (item-wise with measurement), revised, supplementary; detailed estimate uses standard measurement rules.

Measurement units: earthwork in m³, brickwork in m³, plaster in m², painting in m², reinforcement in kg or quintal, doors/windows in numbers (or m²).

Plinth area estimate: cost = plinth area × plinth area rate; plinth area measured at plinth level including walls, excluding open areas and projections.

Cubic content method: cost = volume (length × breadth × height) × unit cubic rate; suitable for preliminary estimate of buildings.

Centre-line method: total centre-line length × breadth × depth for walls; deductions at junctions handled by taking centre-line length and adjusting for wall thickness.

Rate analysis: labour, material, plant, overheads, and contractor profit; standard task work per day (e.g., mason 1 m³ brickwork) used to compute labour cost.

Contingency and work-charged establishment: typically 3-5% contingency, 1-2% work-charged establishment, plus 1% for quality control in public works.

Bill of Quantities (BOQ): item description, unit, quantity, rate, amount; abstract of cost summarises totals; tender is invited on BOQ for item-rate contracts.

Chain surveying: principle of triangulation; ranging rods, arrows, chain/tape; check lines verify framework; offsets measured perpendicular to chain line.

Compass surveying: bearing measured from north; whole circle bearing (WCB) 0-360°, reduced bearing (RB) 0-90° with quadrant; magnetic declination converts magnetic to true bearing.

Levelling: dumpy level, staff; height of instrument (HI) = RL + backsight; RL of new point = HI − foresight; rise and fall method checks arithmetic.

Contouring: contour lines join points of equal elevation; interval depends on scale and purpose; closer contours indicate steeper slope.

Theodolite: measures horizontal and vertical angles; transit and non-transit; face left/face right readings average out instrumental errors.

Total station: combines EDM and angle measurement; records coordinates; used for setting out and as-built surveys; needs control points and orientation.

Setting out a building: establish baseline and reference pillars, use 3-4-5 method for right angles, check diagonals of rectangle, mark grid lines with pegs and lime.

Levels and benchmarks: temporary benchmark (TBM) established on site; reduced level (RL) referenced to datum; check levelling loop closure within permissible error.

Hand tools: trowel (laying mortar), float (finishing), plumb bob (verticality), spirit level (horizontality), mason's line, bolster and chisel for cutting bricks.

Concrete mixers: tilting drum for small works, non-tilting for large; capacity in cubic metres per batch; mixing time typically 1.5-2 minutes after all materials are charged.

Vibrators: internal (needle) vibrator for RCC, surface vibrator for slabs, form vibrator for precast; over-vibration causes segregation, under-vibration causes honeycombing.

Excavators and backhoes: excavator for bulk earthwork, backhoe for trenching; output depends on bucket capacity, cycle time, and soil type.

Compaction equipment: smooth-wheel roller for granular soil, sheep-foot roller for cohesive soil, plate compactor for small areas; compaction increases density and bearing capacity.

Hoists and cranes: tower crane for high-rise, mobile crane for short-term lifts; safe working load (SWL) must not be exceeded; inspection and certification required.

Scaffolding: putlog scaffold (single) for masonry, independent scaffold for tall buildings; standards, ledgers, and transoms; ties to building at regular intervals.

Power tools: cut-off saw, drill, grinder; check guards, insulation, and earthing; use residual current device (RCD) for portable electric tools.

Personal protective equipment (PPE): helmet, safety shoes, high-visibility vest, gloves, goggles, ear protection, and harness for work at height above 1.8-2 m.

Fall protection: guardrails, toe boards, safety nets, and full-body harness with lanyard anchored to a lifeline; fall is the leading cause of construction fatalities.

Excavation safety: shoring or sloping for depths beyond 1.2-1.5 m; keep spoil at least 1 m from edge; check for underground services before digging.

Electrical safety: 110 V site supply for hand lamps, RCD protection, lockout/tagout for maintenance; never use damaged cables or makeshift connections.

Hazard identification and risk assessment: identify hazard, assess likelihood and severity, apply hierarchy of controls (eliminate, substitute, engineer, administrate, PPE).

Fire safety: extinguishers (water, foam, CO₂, dry powder), fire exit routes, hot-work permit, and no smoking near flammable materials.

Health hazards: silica dust from cutting concrete, asbestos in old buildings, noise above 85 dB, heat stress; use wet cutting and dust masks; monitor exposure.

Environmental control: dust suppression, silt traps for runoff, waste segregation, noise limits, and protection of trees and drainage during construction.

Marking and measuring: steel rule, try square, vernier caliper (least count 0.02 mm), micrometer (least count 0.01 mm); measure at eye level to avoid parallax.

Filing: single-cut file for finishing, double-cut for rapid removal; file pressure on forward stroke only; clean with file card; never use without a handle.

Sawing and chiselling: hacksaw blade 18 or 24 TPI for metal; wood saw for timber; chisel bevel angle usually 25-30°; cut away from the body.

Drilling: drill size equals required hole; centre punch before drilling; use cutting fluid for steel; clamp work securely; speed decreases with drill diameter.

Threading: tap for internal threads, die for external; tap drill size ≈ nominal diameter − pitch; use lubricant and reverse to break chips.

Brick and block work practice: soak bricks before laying, full mortar bed and frog filled, plumb and level checked every course, joint thickness 10-12 mm.

Concrete practice: measure materials by volume or weight, mix uniformly, place in layers, compact with vibrator, cure for at least 7 days (14 days for hot weather).

Workplace housekeeping: keep tools in toolbox, clear offcuts and waste, store materials safely, and maintain a clean and organised work area to prevent accidents.

Business plan components: market analysis, technical feasibility, financial projections, organisation and management, and risk assessment; used for loans and permits.

Cost classification: fixed cost (rent, salaries) and variable cost (materials, labour); break-even point = fixed cost ÷ (selling price − variable cost per unit).

Pricing methods: cost-plus, market-based, and value-based; construction contracts often use item rates, lump sum, or percentage rate tenders.

Cash flow management: track receivables and payables; retainage (retention money) typically 5-10% withheld until completion; plan working capital for delays.

Licensing and registration: business registration, GST/tax registration, labour licence, and contractor registration with public works departments for tenders.

Marketing for contractors: portfolio of completed works, client references, quality and safety record, and participation in pre-qualification (PQ) tenders.

Risk management: contract clauses, insurance (workmen compensation, third-party liability), performance bonds, and contingency in estimates.

Record keeping: maintain measurement books, bills, vouchers, labour registers, and statutory records; good records support claims and audits.

CV essentials: personal details, education, skills, work experience, certifications, and references; tailor to the job and keep to 1-2 pages.

Cover letter structure: opening with position applied for, body linking skills to job requirements, closing with availability and request for interview.

Interview preparation: research the organisation, prepare examples using STAR (Situation, Task, Action, Result), and prepare questions for the interviewer.

Workplace communication: clear instructions, active listening, feedback, and reporting; use written records for instructions and changes to avoid disputes.

Technical reporting: daily progress report, site diary, inspection report, and non-conformance report; include date, location, observation, and action taken.

Teamwork and coordination: coordinate with masons, carpenters, electricians, and supervisors; resolve conflicts through discussion and escalation to supervisor.

Digital skills: email, spreadsheets for estimates, CAD for drawings, and messaging apps for site coordination; maintain professional tone in all communication.

Professional ethics: punctuality, honesty in measurement and billing, respect for safety rules, and confidentiality of employer information.