Assertion (A): A small, sunny, west-facing room will seem larger and cooler if painted in light blue. Reason (R): Cool, light colours recede and reflect light. Choose the correct option.

Both A and R are true, and R is the correct explanation of A

Both A and R are true, but R is not the correct explanation of A

Which of the following are recognised principles of house planning? Select all that apply.

Maximum projections to add grandeur

Which factors enter the assessment of thermal comfort? Select all that apply.

The occupant's clothing and activity level

Air temperature and mean radiant temperature

The occupant's clothing and activity level

The colour rendering index of the lamps

Air temperature and mean radiant temperature

Why does a square house plan usually cost less per square metre of floor than a long, narrow plan of the same area?

It needs less length of external wall to enclose the same area

Building regulations tax rectangular plans

Square plans need no foundations

Housing and Interior Design I: Design Fundamentals, Colour, Space Planning and House Plans, Building Regulations and Housing Finance, and Housing and the Environment

Unit VI brings design, the dwelling and energy together. This first chapter takes items 1 to 5: the elements and principles of design and composition applied to interiors; colour, its dimensions and systems, its psychological effects and schemes; the planning of space, from housing need and the principles of planning to kitchen layouts, economy in construction and plans for different income groups; building regulations, zoning, housing for special groups and areas, and housing finance; and housing and the environment, with building materials, green rating systems, energy efficiency codes, energy auditing and the indices of indoor comfort. The next chapter takes energy as a resource, product design, ergonomics, furniture and furnishings and the research slice on tools, scales, reliability and validity.

1. Design fundamentals: elements of art, principles of design and composition

The elements of art are the raw materials of any interior: line (vertical lines suggest height and formality, horizontal lines rest and width, diagonals movement, curves grace), form and shape, space (positive, occupied, and negative, empty), colour, texture, light and pattern. The principles of design govern how they are arranged: proportion and scale (the size of parts relative to each other and to the room and its users), balance (formal or symmetrical, informal or asymmetrical, and radial), rhythm (repetition, gradation, radiation, alternation, transition), emphasis (a focal point such as a fireplace, a window view or a piece of art) and harmony or unity with variety. Composition brings these into a whole: a room is judged by whether its parts relate, whether the eye moves comfortably through it, and whether it fits its function and its occupants.

🧠 Scale is about the room and the user

Proportion compares parts of an object with each other; scale compares the object with its surroundings and with people. A massive sofa in a small flat is a failure of scale even if the sofa itself is well proportioned.

2. Colour: dimensions, systems, psychological effects and schemes

Colour has three dimensions. Hue is the name of the colour (red, blue). Value is its lightness or darkness: adding white gives tints, adding black gives shades. Intensity or chroma is its brightness or dullness: adding grey or the complement gives tones. The Prang (Brewster) system builds a twelve-hue wheel from the primaries red, yellow and blue, their secondaries orange, green and violet, and six intermediates. The Munsell system describes every colour by hue, value (on a scale from 0, black, to 10, white) and chroma, around five principal hues. Light mixes additively (red, green and blue light make white); pigments mix subtractively.

Colour scheme	Construction	Effect
Monochromatic	Tints, tones and shades of one hue	Restful, unified; can be dull without textural variety
Analogous	Three to five neighbouring hues on the wheel	Harmonious, easy to live with
Complementary	Two hues opposite on the wheel	Lively contrast; one hue should dominate
Split-complementary	A hue and the two on either side of its complement	Contrast with less tension
Double complementary	Two adjacent hues and their complements	Rich, needs careful balance
Triad	Three hues equally spaced, 120 degrees apart	Vibrant; usually softened in tints or tones
Neutral and accented neutral	Whites, greys, beiges, browns; with a small accent of a strong hue	Calm, flexible backdrop

Warm colours (reds, oranges, yellows) are stimulating and advancing: they make walls seem nearer and rooms smaller and cosier. Cool colours (blues, greens, violets) are calming and receding: they make rooms seem larger and cooler. Light values reflect light and enlarge; dark values absorb it and enclose. The choice of colour depends on the room's function, orientation and sunlight (in much of India, rooms facing south and west receive hot afternoon sun and benefit from cool colours), size, the occupants' age and preferences, the lighting, the existing furnishings and the climate.

3. Space planning: housing need, principles of planning, house plans and economy

Housing meets needs at every level of Maslow's hierarchy: shelter and health, security and privacy, family life and belonging, status and self-expression. A well-planned house follows the principles of planning: aspect (placing rooms to receive sun and breeze appropriately), prospect (outlook from windows), privacy (within the house and from outside), grouping (related rooms together, such as kitchen near dining), roominess (the most use from the least area), furniture requirements, sanitation (light, ventilation and hygiene), flexibility (spaces that serve more than one use), circulation (short, uncluttered passages), elegance and economy.

House plans may be detached, semi-detached, row (terraced) or apartments, single or multi-storey, closed plan (separate rooms) or open plan (combined living, dining and kitchen), and arranged around a courtyard, as in many traditional Indian homes.
The kitchen is planned around the work triangle joining the storage (refrigerator), preparation and wash (sink) and cooking (stove) centres; a commonly advised total length is about 3.6 to 7.9 m (12 to 26 feet). Layouts are one-wall, galley (corridor), L-shaped, U-shaped, island and peninsula; the U and L shapes usually give the most efficient triangle.
Economy in construction comes from compact plans (a square encloses more area for its perimeter than a long rectangle), fewer corners and projections, standard sizes and modular coordination, local materials, cost-effective techniques such as the rat-trap bond and filler slabs popularised by Laurie Baker, good supervision and phased construction.
Planning for income groups: under the Pradhan Mantri Awas Yojana, economically weaker section households have annual incomes up to 3 lakh rupees and low-income group households 3 to 6 lakh rupees; an EWS house under PMAY-Urban has a carpet area of up to 30 square metres. Plans for these groups stress multipurpose rooms, minimum circulation, shared walls and scope for incremental expansion.

4. Building regulations, zoning, special groups and housing finance

Building regulations protect safety, health and the neighbourhood. The National Building Code of India 2016, published by the Bureau of Indian Standards, sets norms for development control, structural safety, fire and life safety, services and sustainability, and local building bye-laws adapt them. Key controls are the floor area ratio (FAR, or floor space index: total built-up floor area divided by plot area), ground coverage (the share of the plot the building may cover), setbacks (open space to be left from the boundaries), height limits, minimum room sizes, and light and ventilation openings. On a 200 square-metre plot with a permitted FAR of 1.5, the total floor area that may be built on all floors is 200 × 1.5 = 300 square metres. Zoning divides a city's land by use (residential, commercial, industrial, institutional, green belt, mixed) and by density, through the master plan.

Housing for special groups: older persons and persons with disabilities need barrier-free design, including ramps no steeper than 1 in 12, wide doors, grab bars, level thresholds and accessible toilets, as the Rights of Persons with Disabilities Act 2016 and the national guidelines on universal accessibility require; housing is also planned for working women, students, migrant workers and the homeless.
Housing for special areas: earthquake-resistant construction in seismic zones, raised plinths and flood-resistant materials in flood-prone areas, cyclone-resistant roofs on the coast, and coastal regulation zone limits.
Housing finance comes from banks, housing finance companies, HUDCO (1970) for public housing and infrastructure, and the National Housing Bank (1988), which regulates and refinances housing finance. The Real Estate (Regulation and Development) Act 2016 requires projects and agents to register with a state authority and project funds to be kept in a separate account. The Pradhan Mantri Awas Yojana (Urban from 2015, Gramin from 2016, replacing the Indira Awaas Yojana) supports house construction and purchase for poorer households, and was extended in 2024.

5. Housing and the environment: materials, green ratings, energy efficiency, auditing and indoor comfort

Buildings consume materials, land, water and energy throughout their life. Cement, steel, aluminium and fired clay bricks carry high embodied energy (the energy used to extract, make and transport them); lower-impact alternatives include fly ash bricks, compressed stabilised earth blocks, autoclaved aerated concrete blocks, bamboo, recycled materials and local stone. Green rating systems assess a building's site, water, energy, materials and indoor environment. GRIHA (Green Rating for Integrated Habitat Assessment), developed by TERI and adopted by the Ministry of New and Renewable Energy as the national rating system, awards one to five stars; the Indian Green Building Council, part of the Confederation of Indian Industry, rates buildings Certified, Silver, Gold or Platinum; LEED, of the US Green Building Council, uses the same four levels internationally.

The Energy Conservation Building Code, first issued by the Bureau of Energy Efficiency in 2007 and revised in 2017, sets minimum energy standards for large commercial buildings at three levels: ECBC compliant, ECBC Plus and Super ECBC. Its residential counterpart, Eco-Niwas Samhita (2018), sets standards for the building envelope of homes. An energy audit examines how a building uses energy and where it can save: a preliminary (walk-through) audit identifies obvious savings, a detailed audit measures every major load. Its headline indicator is the energy performance index, annual energy use divided by built-up area: a building of 1,000 square metres using 1,50,000 kWh a year has an EPI of 150 kWh per square metre per year.

Index of indoor comfort	What it depends on
Thermal comfort	Air temperature, mean radiant temperature, humidity and air velocity, with the occupant's activity (metabolic rate) and clothing; summarised in Fanger's predicted mean vote and predicted percentage dissatisfied
Visual comfort	Illuminance (lux) suited to the task, daylight factor, uniformity, freedom from glare, colour rendering
Acoustic comfort	Background noise level in decibels, insulation between spaces, reverberation
Indoor air quality	Ventilation rate (carbon dioxide is a common indicator), particulate matter from cooking fuels, volatile organic compounds from paints and furniture, moisture and mould

⚠️ GRIHA uses stars, IGBC and LEED use metals

GRIHA rates one to five stars; IGBC and LEED certify at Certified, Silver, Gold and Platinum levels. ECBC is not a rating but a code with minimum requirements, and BEE star labels rate appliances, not buildings.

Key takeaways

The elements of art (line, form, space, colour, texture, light, pattern) are arranged by the principles of proportion and scale, balance, rhythm, emphasis and harmony.
Colour has hue, value (tints and shades) and intensity (tones); warm colours advance, cool colours recede; schemes are monochromatic, analogous, complementary, split-complementary, double complementary, triad and neutral.
Planning principles include aspect, prospect, privacy, grouping, roominess, circulation, flexibility and economy; the kitchen work triangle joins storage, sink and stove.
FAR = total floor area / plot area; the National Building Code 2016 and local bye-laws control FAR, coverage, setbacks and heights; RERA 2016 and PMAY shape housing finance and access.
GRIHA (stars), IGBC and LEED (Certified to Platinum) rate green buildings; ECBC 2017 and Eco-Niwas Samhita 2018 set energy codes; EPI = annual kWh / built-up area.

Practice questions (10)

Attempt each one before opening the answer. Every explanation names the tempting wrong option as well as the right one, because that is where marks are lost.

A plot measures 200 m² and the permitted floor area ratio is 1.5. What is the maximum total floor area, in m², that may be built on all floors together? Type the number.
Numerical answer — type the value.
Show answer
Answer: 300
FAR = total floor area / plot area, so total floor area = 200 × 1.5 = 300 m². How it is split between floors then depends on the permitted ground coverage.
An office of 1,000 m² built-up area uses 1,50,000 kWh of electricity a year. What is its energy performance index in kWh per m² per year? Type the number.
Numerical answer — type the value.
Show answer
Answer: 150
EPI = annual energy use / built-up area = 1,50,000 / 1,000 = 150 kWh per m² per year. Comparing EPIs lets buildings of different sizes be benchmarked against each other.
Adding white to a hue produces a:
1. Shade
2. Tone
3. Tint
4. Complement
Show answer
Answer: C — Tint
White raises value and makes a tint; black lowers value and makes a shade; grey or the complement lowers intensity and makes a tone. A complement is the hue opposite on the colour wheel.
A living room is decorated in yellow-green, green and blue-green, with tints and shades of each. The colour scheme is:
1. Analogous
2. Triad
3. Monochromatic
4. Complementary
Show answer
Answer: A — Analogous
Yellow-green, green and blue-green are neighbours on the wheel, which makes an analogous scheme. Monochromatic would use one hue only, complementary two opposite hues, and a triad three hues 120 degrees apart.
Assertion (A): A small, sunny, west-facing room will seem larger and cooler if painted in light blue. Reason (R): Cool, light colours recede and reflect light. Choose the correct option.
1. Both A and R are true, and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. A is false, but R is true
Show answer
Answer: A — Both A and R are true, and R is the correct explanation of A
Both are true and R explains A. Blue is a cool, receding hue, and a light value reflects light, so the walls seem farther away and the room feels less hot, which suits a west-facing room that takes the afternoon sun.
Which of the following are recognised principles of house planning? Select all that apply.
1. Aspect
2. Circulation
3. Grouping
4. Maximum projections to add grandeur
Show answer
Answer: A — Aspect; B — Circulation; C — Grouping
Aspect, grouping and circulation are standard principles, with prospect, privacy, roominess, flexibility, sanitation, elegance and economy. Needless projections add cost and are what economy in construction avoids.
Which green building rating system awards one to five stars and was adopted as India's national rating system by the Ministry of New and Renewable Energy?
1. ECBC
2. LEED
3. GRIHA
4. IGBC
Show answer
Answer: C — GRIHA
GRIHA, developed by TERI, is the national star-rating system. LEED and IGBC certify at Certified, Silver, Gold and Platinum levels, and ECBC is an energy code with minimum requirements rather than a rating.
Which factors enter the assessment of thermal comfort? Select all that apply.
1. The occupant's clothing and activity level
2. The colour rendering index of the lamps
3. Air temperature and mean radiant temperature
4. Humidity and air velocity
Show answer
Answer: A — The occupant's clothing and activity level; C — Air temperature and mean radiant temperature; D — Humidity and air velocity
Thermal comfort depends on four environmental factors (air temperature, radiant temperature, humidity, air velocity) and two personal ones (clothing and metabolic rate), as in Fanger's model. Colour rendering is a visual comfort measure.
Under the Pradhan Mantri Awas Yojana, an economically weaker section household is one with an annual income of:
1. 3 to 6 lakh rupees
2. Up to 3 lakh rupees
3. Above 18 lakh rupees
4. Up to 1 lakh rupees
Show answer
Answer: B — Up to 3 lakh rupees
EWS households have annual incomes up to 3 lakh rupees, and low-income group households from 3 to 6 lakh rupees. An EWS house under PMAY-Urban has a carpet area of up to 30 square metres.
Why does a square house plan usually cost less per square metre of floor than a long, narrow plan of the same area?
1. It needs less length of external wall to enclose the same area
2. Building regulations tax rectangular plans
3. Square plans need no foundations
4. Square rooms need no windows
Show answer
Answer: A — It needs less length of external wall to enclose the same area
For a given area, a square has the smallest perimeter of any rectangle, so it needs less external wall, fewer corners and less finishing, which is a core principle of economy in construction. The other options are false.