Short, plain-language explanations of terms and calculations that come up constantly on site and in exams — no fluff, just the answer and why it matters.
How to calculate cement bags, sand and aggregate (in m³ and cft) for 1 m³ of M20 nominal mix concrete, with the 1.54 dry volume factor and a worked site example.
Nominal mix ratios from M5 to M20, why M25 needs a design mix, IS 456 grade groups, minimum grades for RCC by exposure and where each grade is used on site.
Step-by-step roof slab estimate: concrete volume, wastage, cement bags, sand and aggregate in m³ and cft, mixing water and a steel thumb rule for a 12 m × 10 m slab.
How to calculate the concrete volume of an isolated footing: rectangular block, sloped (trapezoidal) part by the prismoidal formula, and the PCC bed, with a full worked example.
How to do the slump test as per IS 1199, how to read true, shear and collapse slump, IS 456 slump values for each type of work, and what to do when slump is off.
Bricks per cubic metre for modular and traditional sizes, mortar and 1:6 cement-sand quantities, bricks per m² of 115 mm and 230 mm walls, with a worked example.
How to calculate cement and sand for 12 mm and 20 mm cement plaster per 100 m², with the wet-to-dry factor, wastage and a worked example for a room.
Unit weights and densities of concrete, steel, brick, stone, cement, sand, aggregate, water, timber and glass, with a worked dead-load example for a slab and a wall.
Simple site checks for cement quality and the IS 4031 lab tests (fineness, consistency, setting time, soundness, strength) with OPC limits and a worked example.
Quick site tests for bricks (size, colour, sound, scratch, drop, soaking, efflorescence) and the IS 1077 / IS 3495 lab tests and classes, with worked examples.
IS 456 lap length rules for tension and compression, a ready table for 8–25 mm Fe500 bars in M20 and M25, staggering rules and where you must never lap.
IS 456 nominal cover for each exposure class, the column and footing minimums, the covers actually used on Indian sites, and how to place cover blocks properly.
Why steel weight per metre is D²/162, a ready kg/m and 12 m bar weight table for 6–32 mm TMT bars, typical bundle counts and a step-by-step worked example.
IS 1786 properties of Fe415, Fe500, Fe550 and their D grades, when each makes sense, how to check TMT bars at site, and how grade changes xu,max/d and steel area.
IS 456 formwork stripping times for columns, slabs and beams, how cold weather and PPC/PSC cement change them, a worked de-shuttering schedule and safety tips.
Riser, tread, width, headroom and landing rules for house stairs, the 2R+T comfort check, and a full worked design for a 3.0 m floor height.
Minimum areas, widths and heights for habitable rooms, kitchen, bath, WC and garage per NBC 2016 Part 3, plus ventilation rules, with a worked 2BHK plan check.
Approximate cement, steel, sand, aggregate, bricks, tiles and paint for a 1000 sq ft RCC framed house, with per-sq-ft ranges and how to get an exact quantity.
Formulas to get litres from tank dimensions (rectangular and round, metres and feet), daily water demand per CPHEEO, and sizing an overhead tank and sump for a family.
What VG-10, VG-20, VG-30 and VG-40 mean, how viscosity grading replaced penetration grades, where each grade is used, and the IS 73:2013 test limits.
A free 2D frame, beam and truss analysis tool: draw the structure, assign real supports and internal hinges, apply loads, and get the BMD and SFD with values.
What a BMD and SFD actually represent, why their shapes always pair the way they do, and the fastest way to sanity-check one.
Why a structure needs a deliberate zero-moment release, how a Gerber beam can be solved segment by segment, and where hinges show up in real construction.
What actually changes between a Pratt, Howe and Fink truss, why the diagonal direction matters more than the name, and why wind can flip your assumption.
The dome-cylinder-cone-dome profile isn't decoration — each curve cancels a specific thrust. The logic, part by part.
Why a curved ring beam carries torsion no straight beam ever sees, and how the classic three-ring design handles it.
First, second and third class bricks, fly ash bricks and engineering bricks — what separates them and where each belongs.
Where the DPC goes, what rising damp actually does to a wall, and the common DPC materials used on site.
Impulsive vs convective mass, why full and empty tanks behave like different structures, and why IS 1893 gives tanks their own dedicated part.
Why COD is always the bigger number, and how the BOD/COD ratio tells you whether a wastewater is even treatable biologically.
What w/c ratio actually controls, why more water isn't the fix it looks like, and the IS 456 limits by exposure condition.
Chain, compass, dumpy level, theodolite, total station and GNSS — what each one measures and when it's the right tool.
The Ly/Lx span-ratio rule, why the load 'picks' a direction, and what actually changes in the reinforcement layout.
Why the column grid decided on the architectural plan drives beam depth, slab thickness and foundation size downstream.
Three different questions, three different documents — and what goes wrong when they get used in place of each other.
Why a BBS controls steel wastage, how hooks/bends/laps affect cutting length, standard bar shapes, and a worked example.
Strength gain, heat of hydration and durability compared across the three most common cements, and how to pick between them.
Isolated, combined, strip, raft and pile foundations — how each works and what actually decides the choice between them.
Ceramic, vitrified and porcelain tiles; Indian and Italian marble, granite, Kota stone and sandstone — what each one is, where it fits, and how to choose.
Alligator cracking, rutting and reflection cracks in flexible pavements; corner breaks, joint spalling and blowups in rigid pavements — causes and remedies.
What curing actually does, the methods used on site, minimum curing periods per IS 456, and what goes wrong when it's skipped.
Plastic shrinkage, drying shrinkage, thermal, settlement, structural and corrosion cracks — how to tell them apart and how each is repaired.
A column's effective length isn't its physical height — it depends on how its ends are restrained. Here's why that matters for design.
Why a reinforcement bar needs a minimum embedment length to actually do its job, and the formula behind it.
From bar bending schedule to total tonnage — the practical way site engineers estimate steel requirement.
Trapezoidal method, common mistakes, and a worked example for excavation quantity.
Two terms that get used interchangeably on site, but actually mean different things in foundation design.
Why pavement designers care about CBR, how the test works, and what a 'good' value looks like.
Two pavement layers that get confused constantly — where each sits, what it does, and why the order matters.
A plain-language look at one of the most common sub-base/base layers in Indian road construction.