
Written by: Ajay Abey, Tara Eugine Pandala
6 min readNew DelhiUpdated: Jul 15, 2026 02:10 PM IST
Do not add an alternate roof without first considering applicable setback requirements, planning regulations, and the overall architectural character of the building (Photo: CSBNE)
Traditional Indian roof forms are shaped by climate, local materials, construction techniques and cultural traditions. Regions with heavy rainfall favour steeply sloping roofs with generous overhangs; snow-bound Himalayan areas use steep slate or shingle roofs to shed snow, while hot-arid regions like Rajasthan predominantly use flat terraces that provide usable outdoor space and benefit from the thermal comfort of a natural stone and lime building.
But, nowadays, most of our homes and, by default, our roofs are built from Reinforced Cement Concrete (RCC), regardless of the climatic region. And, as we often see, over time these roofs develop leaks and surface deterioration due to weather-induced wear. Their large, exposed surfaces cause heat to be absorbed and retained in a building. Which is why the temperature within your house is elevated and being indoors is as insufferable as being outside.
So, can there be better solutions besides the regular flat slabs in our homes? Roofs that can improve drainage, minimise water ingress, reduce heat gain, and enhance long-term durability? Here are some solutions:
Make the roof climate-sensitive
Be mindful of your region’s seasonal variations and design your roof to respond effectively to the local climate. Ensure safe and efficient rainwater drainage. The roof should incorporate an adequate slope to facilitate rapid runoff, prevent water stagnation and minimise the risk of leakage and structural deterioration.
What is the right slope?
It’s not always in your hands, but during construction or when you build upper floors onto an existing apartment, keep this in mind: RCC flat roofs should be designed with a minimum slope of 2–2.5 per cent (approximately 20–25 mm per metre) directed towards drainage outlets. Tiled roofs should generally be designed with slopes ranging from 15 to 30 degrees or higher, depending on the tile type and local rainfall intensity. For metal roofing systems using aluminium or GI sheets, a minimum slope of 5 to 10 degrees is recommended, while slopes up to 15 degrees should be considered in regions with high rainfall to facilitate rapid runoff and improve long-term efficacy.
A pitched GI roof can provide additional space, for a home office, a fitness area or a gathering space (Photo: CSBNE)
Waterproofing
There are multiple options under different brand names for waterproofing that are available in the market. Some of these include liquid-applied polyurethane membranes, polymer-modified cementitious coatings, bituminous membrane systems, acrylic waterproofing coatings, synthetic rubber or thermoplastic sheet membranes, crystalline waterproofing treatments and composite roof systems incorporating non-corrosive metal sheet coverings. Effective waterproofing requires proper surface preparation, including a clean, crack-free substrate and adequate roof slope to avoid water ponding. Regular maintenance and timely repairs are essential for long-term performance.
Other ways to prevent roof leaks
If all you have is a flat RCC slab as a roof, consider installing a lightweight sloping roof supported on a steel framework. A roof pitched at approximately 30 degrees and clad with GI or aluminium sheets promotes efficient rainwater drainage while protecting the existing RCC slab. Incorporating terracotta or ceramic roof tiles on such a roof can create a multi-layered system with a ventilated air gap, enhancing weather protection and reducing heat transfer.
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In tropical regions, sloping roofs can also reinforce the regional architectural character and cultural identity of the place. If you do prefer a flat roof, consider transparent UV-resistant sheet coverings, which will be visually appealing and will allow natural daylight into the covered space.
All steel parts of the roof should be given protective coatings or anti-rust paint to minimise corrosion (Photo: CSBNE)
Your covered roof need not be a dead space
A pitched GI roof can provide additional space, which can be your home office, a fitness area, a gathering space, storage or utility zone. It can be a cost-effective means of creating additional cover, saving almost 60 per cent of the actual cost of building a new floor. But ensure the newly created space is carefully integrated into the overall building design to accommodate for future adaptability.
Get structural assessment done
Do not proceed with the installation of a steel roofing system without first assessing the load-bearing capacity of the existing structure. Consult a qualified structural engineer. Any strengthening measures should be done prior to getting that roof installed. Do not overlook the need for adequate anchoring and connection details, so that the roof can resist wind uplift and prevent damage during high winds or storms.
Tiled roofs should generally be designed with slopes ranging from 15 to 30 degrees or higher, depending on the tile type and local rainfall intensity (Photo: CSBNE)
Be mindful of building regulations
Do not add an alternate roof without first considering applicable setback requirements, planning regulations, and the overall architectural character of the building. Failure to address these aspects may result in regulatory non-compliance, functional constraints, and an adverse impact on the visual coherence and aesthetics of the built form.
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The details: roof drainage
Don’t neglect the need for properly designed rainwater drainage systems and collection gutters. This is essential for effective rainwater harvesting and water conservation.
Finally, beware of corrosion for steel roofs
Do not leave steel structural components of the roofing system exposed. All steel members should be provided with appropriate surface treatments, protective coatings, galvanising, or anti-rust paint systems to minimise corrosion.
Architects Ajay Abey and Tara E Pandala are Directors of the Centre for Sustainable Built and Natural Environment (C.S.B.N.E.), Kochi, Kerala. Their practice is dedicated to creating biodiversity-inclusive and sustainable built environments across the institutional, residential and hospitality sectors. The firm also engages in the research, development, and application of alternative building technologies, while actively contributing to heritage conservation and urban design initiatives.
The Home Edit is a weekly series curated by Shiny Varghese that invites architects and designers to share their hands-on expertise on ideas for your home. Whether you are building, renovating, or simply refreshing a space, the series provides actionable advice and inspiration to help you make better choices for where you live. In this part of the series, Ajay Abey and Tara Eugine Pandala share tips on roof management.
View original source — Indian Express ↗



