Sketch My House

Guide

A first-time builder's checklist, in the order it matters

Twenty things, sequenced. Most of them cost nothing and all of them are cheaper before the first brick than after.

Where first-time builders lose money before work starts

You buy a plot and want to start building immediately. You look at floor plans online or ask a builder for an estimate before you define your requirements.

This ordering creates expensive waste. When you change a room layout after masonry starts, you pay twice for materials and labor. When you discover your borewell sits too close to your septic tank, you cannot move either without abandoning expensive work already in the ground.

Building follows a strict order. If you skip steps or reverse them, your budget disappears into site corrections.

The required sequence and the numbers that govern it

House design follows five mandatory phases. The sequence is fixed: establish the land, write the brief, set the envelope, place the rooms, pass the doors, and then locate the services.

Planning also requires budgeting anchors. In 2026 across India, construction costs run ₹1,600–2,000 per sq ft for basic finish, ₹2,000–2,800 per sq ft for standard finish, and ₹2,800–4,500+ per sq ft for premium work. On a 995 sq ft house we drew, a basic rate of ₹1,700 per sq ft gives an estimate of about ₹16.9 lakh. These are planning estimates, not quotations. Only a local contractor with finished structural drawings can quote a firm price.

The physical rules come from established standards:

ItemDimension or ruleSource
Plinth height above ground+600 mm with a planted swaleOur measured practice
Septic tank to borewellMinimum 18 m separationTNCDBR 2019 and IS 2470
Septic tank to buildingMinimum 15 m, or vent rises 2 m above roofIS 2470
Foul drainage slope100 mm diameter pipe at 1:48 fallIS 1742
Corridor clear widthMinimum 914 mm inside partition facesNBC Part 3
Room circulation minimumMinimum 914 mm clear passageNBC Part 3
Clear floor beside bed914 mm preferred; 600 mm absolute floorOur practice and IS 8888
Front clearance at W.C.Minimum 760 mmOur measured practice
Kitchen work aisle1220 mm between facing countersOur measured practice
Water supply per person135 litres per dayIS 1172
Structural masonry bandingBands installed to prevent earthquake failureIS 4326 and IS 13828

How to apply the sequence step by step

Start by establishing the land boundaries. Check deed dimensions against the actual physical perimeter. On a plot in Coimbatore district, deed records showed 5,283 sq ft while shoe-string coordinate calculation showed 5,416 sq ft. Resolve discrepancies before drawing lines.

Next, decide what cannot change. You must decide bedroom count, kitchen orientation, plumbing core locations, and waste disposal before drafting. On a 40 × 60 ft plot, the diagonal is roughly 22 m. Because the Tamil Nadu Combined Development and Building Rules 2019 and IS 2470 require 18 m between a borewell and a septic tank, you must fix these at opposite plot corners immediately. On a 30 × 40 ft plot, an 18 m separation cannot fit, meaning the site must depend on municipal water and sewer lines.

Decisions about tile patterns, paint colors, and kitchen joinery finishes can wait. Structural dimensions cannot.

Next, set the envelope using your plot setbacks. On a 30 × 40 ft plot with 1,200 sq ft of land, standard setbacks reduce the built footprint to about 560 sq ft. That area fits two bedrooms. On a 40 × 60 ft plot of 2,400 sq ft, the envelope is about 1,200 sq ft, which fits three bedrooms.

Place rooms using clear circulation. The National Building Code Part 3 requires 914 mm for corridors. In bedrooms, our practice requires 914 mm clear on each side of the bed. Fit the furniture to the room, not the reverse. In a 3,300 mm wide room, a 1520 mm queen bed leaves 890 mm per side. That is 24 mm short of the 914 mm standard. Using a 1370 mm double bed in that 3,300 mm room leaves 965 mm clear, satisfying the standard.

Run a dedicated door review. Every door leaf must sit inside a real wall. Our practice sets a warning whenever a door leaf clears an internal fixture by less than 50 mm.

Finally, lay out services. Build the plinth at +600 mm above finished ground level with a planted swale falling away on all sides. Install horizontal seismic bands to IS 4326 and IS 13828. Embed all electrical conduit, switch back-boxes, soil pipes, and vent ducts directly into the masonry as the walls rise. If you build using stabilised earth or lime mortars, chasing walls after construction cracks the material.

Demand written documents from everyone you hire:

The mistakes this sequence prevents

Skipping the door review creates physical conflicts. On one internal plan check, a 900 mm bedroom door leaf struck a wardrobe face by 567 mm. On another drawing, a bathroom door hit a vanity counter by 290 mm, forcing the vanity to be shortened.

Skipping clear corridor calculations wastes space. On an unchecked plan, a corridor was drawn at 914 mm from rough masonry. Once 110 mm brick partitions were added, the walking route dropped to 804 mm. That error cost 110 mm of usable clearance along the main path in the home.

Ignoring site sanitation rules causes severe contamination. Placing a septic tank soak pit within 18 m of a borewell violates IS 2470 and risks groundwater fouling. Fixing this after drilling requires abandoning a well or building an off-site connection, costing tens of thousands of rupees.

What this means for your plan

Check your boundary dimensions and confirm that your septic tank sits at least 18 m from your water source. Ask your structural engineer to verify that seismic bands follow IS 4326 before masonry starts. The planning tool checks these clearances, door swings, and setback limits automatically when generating your initial layout. You can take that verified brief directly to your licensed architect or engineer for permit drawings.

Sources

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Related

The five bedroom placement mistakes that cost the most to fixBedrooms go wrong in the same five ways, and every one of them is decided in the first hour of planning. Where a door goes, and what you see when it opensA door is placed twice: once for the swing, once for the view through it. Most plans only do the first. What actually fits on a 30 × 40 plot1,200 sq ft of land. After setbacks you have about 600 to build on — and that is a good two-bedroom house, not a bad three.