Make Your Home Heatwave-Safe: NDMA Guide Provides Roof Cooling Solutions
When roofs are cooled through the use of reflective materials and techniques, they help reduce heat absorption and improve the overall thermal comfort of the building.
The National Disaster Management Authority has issued a handbook that aims to guide homeowners with roof cooling solutions and materials that are affordable and easy to use in existing homes.
India is likely to experience a warmer summer and more heatwave days this year with El Nino conditions predicted to continue at least until May, the India Meteorological Department recently said.
Need For Cool Roofs
The roof contributes up to 70% of the heat gain of a building during high temperatures. Solar radiation striking a surface is either reflected, absorbed, or transmitted. When roofs are cooled through the use of reflective materials and techniques, they help reduce heat absorption and improve the overall thermal comfort of the building.
Alternate Roof Cooling Solutions
Bamboo, Thatch and Palm Leaves Roof Screen
Bamboo, thatch and palm leaves are locally available across India and can be installed as a secondary roof screen, thereby reducing the heating effect.
Green Net Shading
Green net shading is the most basic strategy to achieve thermal comfort. Depending on its design and positioning, varied degrees of thermal comfort can be achieved
Roof Mist Cooling
A roof mist cooling system reduces the roof surface temperature by spraying an extremely small amount of water across the roof. Spraying allows to cool the roof as the water evaporating from the surface captures the heat.
Cool Roof Paint
Cool roof coatings are applied to steep as well as low-sloped roofs. Coatings can be applied to both new and existing roofs.
Gravel Roof
Tar and gravel roof is also termed as built-up roofing (BUR). It is easy to apply and repair and is inexpensive to install. Bitumen provides the waterproofing agents and adhesive properties of the system.
Modified Bitumen Membrane
Modified bitumen roof is one of the most common cool roof options for low-sloped or flat roofs. They come in pre-coated colours, which increases the solar reflectance, resulting in better cooling properties.
Thermoplastic Membrane
Thermoplastic membranes are made from plastic polymers. The membranes do not require any coating as the product itself is integrated with cool roof properties. They are manufactured with self-cleaning and mould-resistant polymers to maintain solar reflectance.
Heat Insulation Tiles
Tile is a resilient material and can withstand hail, wind and fire. Heat insulation tiles are made from PCM (phase change material) technology designed to control the flow of heat from the roof and is used as a surface resistant.
Hollow Terracota/ Concrete Tiles
Hollow concrete/terracotta tiles have high thermal insulation and sound insulation properties, which is very effective in limiting heat flow. The air inside the cavities provides the insulation to heat.
Inverted Earthen Pots
Using earthen pots to keep roofs cool has been traditionally practiced in hot and dry areas. Locally available earthen clay pots are affordable and exhibit high thermal insulation properties.
Mud Phuska
Mud-phuska is prepared from puddle clay mixed with 'bhusa' (chopped straws) and cow dung. It is equally suitable for arid regions and is commonly used over R.C.C roofing.
Extrude Polystyrene (XPS Sheets)
Polystyrene foam has good resistance to the flow of heat and sound and is a commonly used raw material for insulation boards in the construction industry.
Lime Concrete
Brick jelly-lime concrete has traditionally been used as a weathering layer over roofs. The principle is to install a layer of concrete made with lime-'surkhi' mortar with broken brick as coarse aggregate.
Broken China Mosaic
China mosaic terrace provides a reflective layer to the roof, which reflects a considerable amount of solar radiation falling on the roof. The reflective layer is formed by broken and randomly sized pieces of light coloured ceramic tiles, laid on a cement mortar bed, with joints between tiles sealed with white cement.
Thermocrete Insulation
Air cavities inside a material increase its ability to obstruct the transfer of heat or cold through it. Cement concrete finish, which is conventionally used in terraces, can be improved for thermal performance by introducing a layer of thermocrete prepared and poured in-situ at site.
Cellulose Fibre
Cellulose is one of the most environment-friendly raw materials for insulation sourced from recycled paper and cardboards. The fibre gets coated with cement, sand and mortar such that on drying, many air pockets are left inside, giving the dried material an insulating property.