Building Materials for a House in Delhi NCR: Fly Ash, Stone and Beating the Heat

For a house in Delhi NCR, build the walls in fly ash brick or AAC block, put insulation and a reflective finish on the roof, floor it in Kota stone or sandstone, and have the frame detailed for Seismic Zone IV. The same house has to handle January nights near 7°C, May days near 40°C, a short heavy monsoon, and ground in the earthquake code's second-highest zone.

The climate, ground and earthquake facts that decide it

A composite climate: hot, cold and wet in one year

IMD's climatological table for New Delhi (Safdarjung), 1991 to 2020 gives a mean daily maximum of 39.9°C in May and a mean daily minimum of 7.5°C in January. Annual rainfall averages 762.3 mm over about 41 rainy days, and 631 mm of it (83%) falls from June to September, with August the wettest month at 226.8 mm.

The Bureau of Energy Efficiency's Eco Niwas Samhita 2018, the energy code for homes, puts New Delhi in the composite climate zone: keep heat out most of the year, hold some warmth in winter, and shed a lot of water in a few weeks.

The ground: alluvium and a quartzite ridge

The Central Ground Water Board's Delhi state profile describes three landforms: an older alluvial plain on both sides of the NNE to SSW quartzite ridge, the Yamuna flood plain, and the nearly closed Chhatarpur alluvial basin. Plots on deep alluvium and near the ridge can need very different foundations, so our guidance is to budget for a soil investigation and let the structural engineer design from it.

Earthquake and wind

The current Indian earthquake code, IS 1893 (Part 1): 2016, lists Delhi in Seismic Zone IV with a zone factor of 0.24. BIS notified a revised 2025 edition, then withdrew it in early 2026 and reverted to the 2016 standard, as ETV Bharat reported. Gurugram, Noida, Faridabad and Ghaziabad are not named in the code's town list, so ask your engineer to read your site off the zone map. For wind, IS 875 (Part 3): 2015 gives Delhi a basic wind speed of 47 m/s, which matters for parapets, tanks and solar frames.

Walls: fly ash brick, burnt clay brick or AAC

Fly ash and the power-plant rule

MoEFCC's ash notification S.O. 5481(E) of 31 December 2021, which replaced the 1999 notification, lists bricks, blocks and tiles among the approved uses of ash. Its paragraph B(1) makes ash use compulsory for agencies building roads, embankments, shoreline works and dams within 300 km of a plant; the text is reproduced in MoEFCC's reply to the National Green Tribunal. The notification has been amended since (December 2022 and January 2024, per a CPCB direction). The January 2024 amendment, S.O. 05(E), rewrote paragraph B(8): all building construction projects within 300 km of a coal or lignite power plant, including those of "all private agencies", shall use ash bricks, tiles or other ash-based products, provided they are offered at no more than the CPWD or state PWD Schedule of Rates price. Whether this binds a family building its own house is not spelled out, so ask your architect how your local authority applies it; in practice fly ash brick is a sound choice either way.

What the standards ask of each unit

• Fly ash lime bricks: IS 12894: 2002 sets classes by compressive strength. Water absorption must not exceed 20% by mass up to class 12.5, and 15% for higher classes.
• Burnt clay bricks: IS 1077: 1992 sets classes from 3.5 to 35 N/mm², a standard modular size of 190 × 90 × 90 mm, the same 20% and 15% absorption limits, and efflorescence no worse than "moderate" up to class 12.5 and "slight" above it.
• AAC blocks: IS 2185 (Part 3): 1984 covers densities of 451 to 1,000 kg/m³. For the common 551 to 650 kg/m³ band, a Grade 1 block must reach 4.0 N/mm² and conduct no more than 0.24 W/m·K.

Why AAC helps in a Delhi summer

Eco Niwas Samhita's material table gives a thermal conductivity of 0.856 W/m·K for fly ash brick and 0.184 W/m·K for AAC. Using the code's own method (surface resistances 0.13 and 0.04 m²K/W, cement plaster at 0.721 W/m·K), a 230 mm fly ash brick wall with 12 mm plaster each side works out to about 2.1 W/m²K, and a 200 mm AAC wall to about 0.8 W/m²K. These are our illustrative calculations, not test results, but they show why AAC on west and south walls is worth considering.

Two cautions: IS 4326: 2013 names well-burnt bricks and solid concrete blocks for load-bearing masonry, so AAC normally goes in as infill in an RCC frame; and CPWD's AAC item includes RCC bands at sill and lintel level.

Roof: insulate it and make it reflective

Eco Niwas Samhita caps the roof U-value at 1.2 W/m²K in every climate zone. By the code's method, a bare 150 mm RCC slab with 12 mm plaster is about 3.1 W/m²K, well over the limit. Adding 25 mm of expanded polystyrene (0.035 W/m·K in the code's table) under a 40 mm screed brings it to roughly 0.9 W/m²K.

CPWD's schedule carries the usual ways to do this:

• sprayed polyurethane foam over the slab with a protective screed
• heat-resistant terrace tiles with a solar reflectance above 0.70
• high-albedo roof coatings
• glass wool or rock wool under the slab, which suits a retrofit

Pair the insulation with a proper slope to drains. With 83% of the rain arriving in four months, ponding water finds any weak spot in the waterproofing.

Floors, plaster and finishes

Two well-known building stones come from neighbouring Rajasthan. The Indian Bureau of Mines' Minerals Yearbook 2020 review of dimension stones describes Kota stone as a greenish-grey limestone from Kota, Jhalawar and Chittorgarh districts with a natural split, non-slip surface. It also notes large sandstone deposits across Dholpur, Bharatpur, Karauli and other districts of Rajasthan, sold under names such as Dholpur Cream. The BIS standards to quote on an order are IS 1128 for limestone slabs and IS 3622 for sandstone slabs.

• Kota stone: a practical choice for verandas, stairs, terraces and service areas. Inside, vitrified tile is the alternative if you want a polished look.
• Red or cream sandstone: suits paving, steps and wall cladding. Dholpur stone is also used for rough-faced wall lining.
• Plaster and paint: light colours on sun-facing walls. If you leave brick exposed, buy a class with a low efflorescence rating and seal it.

Structure: what Zone IV changes

Most NCR houses are RCC frames. IS 13920: 2016 says its ductile detailing rules shall be adopted for the lateral load-resisting system in Zones III, IV and V. Among other things, it requires:

• concrete of at least M20 (M25 for buildings over 15 m)
• closed links with 135° hooks and an extension of six bar diameters (not less than 65 mm)

For load-bearing masonry, IS 4326 puts an ordinary house in Zone IV in Category D. For one or two storeys that means lintel bands, roof bands, vertical steel at corners, junctions and door and window jambs, and a plinth band where needed.

On site: dust rules in NCR

Delhi's DPCC dust control portal says sites with a plot area of 500 sq m or more must register and self-assess. Smaller projects, which covers most single houses, do not register but must still follow the dust pollution control guidelines. Approvals themselves are covered in our guides to building plan sanction in Delhi and plan approval in Noida.

Local and traditional ideas worth keeping

Exposed brick, deep overhangs and stone still answer the sun and the monsoon. Garden Home Design by Atelier Shreenu in Sohna uses:

• thick load-bearing brick walls and deep overhangs
• ventilators above doors and windows to let hot air out
• verandas roofed with stone slabs resting on steel girders, which the architects say avoids concrete shuttering

Indicative prices: CPWD Delhi Schedule of Rates 2023

For what a whole house costs here, stage by stage, see home construction cost in Delhi NCR, or run your numbers through MOA's home cost calculator.

Mistakes to avoid

• Leaving the roof as bare concrete. The slab alone is well over the code's U-value limit.
• Buying bricks or blocks on price alone. Ask for the BIS standard, class or grade, and a dated test report.
• Building AAC infill without bands. Follow the sill and lintel bands in the CPWD item.
• Skipping ductile detailing. 90° hooks on column ties are a common site shortcut that IS 13920 does not allow.
• Working from the withdrawn 2025 seismic map. Design to IS 1893 (Part 1): 2016 unless BIS notifies otherwise.

FAQ

Which brick is best for house construction in Delhi?

For walls inside an RCC frame, fly ash brick or AAC block both work. AAC keeps out far more heat; fly ash brick is slightly cheaper per brick in the CPWD schedule. For load-bearing or exposed walls, use well-burnt clay brick to IS 1077.

Is fly ash brick compulsory in Delhi NCR?

Since the January 2024 amendment, the ash notification requires building projects within 300 km of a coal or lignite power plant, including private ones, to use ash-based bricks or blocks when they are offered at Schedule of Rates prices. How it applies to a single family house is not spelled out, so check with your architect and local authority.

What is the rate of fly ash bricks in Delhi?

CPWD's DSR 2023 gives a basic rate of ₹4,500 per 1,000 for fly ash bricks to IS 12894, excluding GST and carriage, based on April 2023 Delhi rates. Use it as a reference, not a quote.

Is Kota stone good for flooring in Delhi?

Yes, especially for verandas, stairs and terraces. The Indian Bureau of Mines notes its natural split, non-slip surface. Order it to IS 1128.

Which seismic zone is Delhi in?

Zone IV, with a zone factor of 0.24, under IS 1893 (Part 1): 2016, which is the edition in force after the 2025 revision was withdrawn.

Choosing materials for your plot, orientation and budget is the job of an architect. Find an architect on MOA, or browse studios in Noida.

Sources

• India Meteorological Department: New Delhi (Safdarjung) climatological table, 1991 to 2020 (accessed 16 Oct 2026)
• Bureau of Energy Efficiency: Eco Niwas Samhita 2018, Part I Building Envelope, copy on the UN ESCAP Asia Pacific Energy Portal (accessed 16 Oct 2026)
• Central Ground Water Board: Ground Water Scenario of Delhi (NCT), state profile (accessed 16 Oct 2026)
• Bureau of Indian Standards: IS 1893 (Part 1): 2016, Criteria for Earthquake Resistant Design of Structures (accessed 16 Oct 2026)
• ETV Bharat: A Bold Policy Reversed: The Withdrawal of India's 2025 Seismic Code, 11 March 2026 (accessed 16 Oct 2026)
• Bureau of Indian Standards: IS 875 (Part 3): 2015, Wind Loads (accessed 16 Oct 2026)
• Bureau of Indian Standards: IS 13920: 2016, Ductile Design and Detailing of RC Structures (accessed 16 Oct 2026)
• Bureau of Indian Standards: IS 4326: 2013, Earthquake Resistant Design and Construction of Buildings (accessed 16 Oct 2026)
• Bureau of Indian Standards: IS 12894: 2002, Pulverized Fuel Ash-Lime Bricks (accessed 16 Oct 2026)
• Bureau of Indian Standards: IS 1077: 1992, Common Burnt Clay Building Bricks (accessed 16 Oct 2026)
• Bureau of Indian Standards: IS 2185 (Part 3): 1984, Autoclaved Cellular (Aerated) Concrete Blocks (accessed 16 Oct 2026)
• MoEFCC: reply before the National Green Tribunal in OA 327 of 2022, reproducing ash notification S.O. 5481(E) of 31.12.2021 (accessed 16 Oct 2026)
• Ministry of Environment, Forest and Climate Change: S.O. 05(E), 1 January 2024, amendment to the ash utilisation notification (accessed 17 Oct 2026)
• Central Pollution Control Board: direction of 14.10.2024 on implementation of the ash notification (accessed 16 Oct 2026)
• Indian Bureau of Mines: Indian Minerals Yearbook 2020, Slate, Sandstone and Other Dimension Stones (accessed 16 Oct 2026)
• Central Public Works Department: Delhi Schedule of Rates 2023, Vol. 1 (accessed 16 Oct 2026)
• Delhi Pollution Control Committee: Dust Pollution Control Self Assessment portal, FAQs (accessed 16 Oct 2026)
• MOA: Garden Home Design by Atelier Shreenu, project page (accessed 16 Oct 2026)