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Paint your Roof Top White to Reduce Heat


Roofs of the buildings are exposed to the heat of the sun for the maximum period of the day so the roofs get heated and resultantly this entrapped heat transferred to the rooms below them. Concrete retains heat for long so once heated concrete roofs continuously transfer heat even at night. So we should limit its exposure to the sunlight. There are a number of ways to do so. But we have to choose the best method which should be efficient, cost-effective and needs no structural changes.

White Reflects Heat

You may have heard that light colors reflect heat and dark colors absorb it. It is pertinent to mention that many old civilizations used to paint their buildings white in order to reflect the heat of the sun. Here we take an example when you walk out on a hot day with a black shirt on, you get hotter and when you wear a white shirt you are literally reflecting the sunlight and are comparatively cooler. The same is true for a white colored roof. White colored roof reflects up to 85% or more of the sunlight. 

Rooftop Paint to Reduce Heat

If the roof of your house is not light color or reflective, it will trap the heat of the sun inside the structure and will become hotter. You will have to run the AC much longer to reduce the temperature. Painting your rooftop white pays off immediately. By reflecting light and heat back to the atmosphere, a white roof will reduce your energy costs by keeping your house cool in the summer. 
rooftop-paint-to-reduce-heat


Why Roof Paint Necessary?

White paint is a very effective way of reflecting heat and light from roofs and reducing electricity bills during summer. Painting it white will reflect up to 85 percent of the sunlight and its heat back into the air, eliminating heat trapping. This means you will need an air conditioner for less time. A white painted roof may minimize the building temperature about 2~5C and may reduce your electricity bills in summer season up to 10 to 30 percent. 

New York has recently painted more than ten million square feet of rooftops white. California has updated its building codes to promote white roofs. Such type of pilot projects are already started in In Indian states Bhopal, Ahmedabad, and Hyderabad where they used lime wash to paint which proved to be inexpensive but need to repaint every year.

See this youtube video to understand the effect of white paint on the roof

We used an infrared thermometer gun to compare the surface temperatures of an unpainted area of the roof and another part of the same roof that had been painted white. As you can see in the picture below that the unpainted section of this roof is 173.3°F, while the white painted section is just 128.8°F. The painted section is about 44°F cooler. That’s a considerable difference in of temperature.
roof-heat-proofing

To further understand the difference you can say that, you can fry an egg on a black colored roof, and you can walk on a white roof in your bare feet.

Watch this video about a White Roof Project.


Cheap Way to Paint Your Rooftop

There are many solar heat reflective paints available in the market for roof heat proofing but they are much expensive and the companies, organizations and rich people can use these paints on the roofs of their buildings so what a common man do regarding heat proofing of his house. There is a very cheap way to whitewash rooftop with a lime wash but it gets washed away very soon and you have to do it, again and again, every year. 
We have brought a unique idea for our readers to paint the roofs which is not only cost effective and affordable but also durable. There is a method of painting the rooftop surface by using white cement. Mix the cement with water to form a viscous liquid that can be applied by brush, an old broom or with a paint roller. One bag of white cement is enough to cover a one thousand square feet surface. Prepare a solution of white cement and an equal quantity of water in a plastic bucket and paint it with a large size paint brush. You can apply 2 or 3 coats for better results.

News in Daily Urdu Jang Newspaper regarding Roof Paintingurdu-roof-painting


Alternate Ways to Protect Your Roof from Sun Light and Heat

There are many other alternative ways to avoid heat transfer from the roof to inside your house. 
  1. You can install solar panels on your roof which will not only provide shade and cool effect to your roof but will also generate enough electricity but it requires a huge capital cost.
  2. You can grow small plants and grass on the rooftop but it may need some structural changes in your building to support.

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