Cooling Down Roof in summer
In summers roof of my house always gets very hot and makes almost impossible to sit in the upper lounge without 1.5 ton unit running at 24°C or below. I wanted to find a solution to cool down the roof. Lately I saw an ad of ICI weather shield stating it can bring the temperature 5°C. So I thought to do an experiment on the roof. To my amazement the end result was amazing and actually today I am sitting comfortably in my upper storey lounge without AC while temperatures are :
inside : 33.7°C
Temperature outside: is 41.7°C (in shadow) & 43.5°C (in sunlight). (14th May 2011)
Difference: 7°C to 10°C
However, before the application, I did a recording of temperature, (probably 10 days)
Inside Lounge: 33°C
Outside: 38°C
Difference: 5°C
How I did this ?
The roof of my house is brick layered. I inspected and found it had lots of grime & dust. The only way I found was to remove it using metal wire brush. Here it is what the roof looked like:
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1943.jpg
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1944.jpg
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1945.jpg
So I had to hire laborers to get the roof cleaned with use of water & metal brushes. The result I wanted was red bricks should be visible. This is what it looked after the cleaning.
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1947.jpg
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1948.jpg
The next stages I did were 1 coat of ICI primer and 2 coats of ICI weather shield (5°C cooler - slightly expensive than normal ICI weather shield). The area I covered with this is approximate 750 sqft. In total 2 gallons of ICI primer & 2 gallons of ICI weather shield (5°C cooler) used. ICI primer 1 gallon mixed with 1.5 liter of kerosene oil. 1 gallon could only cover half of 350 sqft. Weather shield was mixed with water 1-1 ratio or may be a little less water. 1 gallon used for 1st coat to cover 750 sqft (approx) 2nd gallon used for second coat.
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1951.jpg
After the application, next day afternoon I checked the white surface with hand and a part of bare surface ( small area where I didn’t needed to apply the coat). The difference was huge to my amazement. I could keep my hand on the white surface as long as I can, but on the bare surface not more than 3-4 seconds.
I do not have a surface temperature meter, but used this digital thermometer. Remember it cannot go above 108°F and below 97.4°F. You can see at the bare surface thermometer rises to its limits and at the white surface it comes down to its lower limit. The difference is very easily noticeable with one hand at bare surface and one at the white surface.
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1956.jpg
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1957.jpg
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1958.jpg
inside : 33.7°C
Temperature outside: is 41.7°C (in shadow) & 43.5°C (in sunlight). (14th May 2011)
Difference: 7°C to 10°C
Inside
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1960.jpg
temperature in Shadow
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1963.jpg
in Sunlight:
http://i72.photobucket.com/albums/i182/vazim/home/IMG_1965.jpg
The trick of weather shield could be white color and material itself as well. I chose white color to get the maximum result, as it reflects sunlight efficiently.
Benefits:
Inner surface (Ceiling) is now cool.
Inner walls are also cool.
Since the roof temperature is not climbing, it is not transferring heat to inner surface (ceiling) and ultimately to inner walls. Hence in the evening, it is now wonderful and I run ac at 28°C-30°C with no one complaining of being hot or whatever :). Before that heat used to transfer to walls, hence making the whole environment hot and impossible to sit without 1.5 ton AC running at 24°C and below even in the evening & night time.
Since Lahore has a very dusty environment, I might have to keep the roof clean every 2-3 weeks. Infact it drizzled yesterday (13th May) and dust stuck to surface, so I used water to get it cleaned. Also smoother the surface, better will be the result.
This could be solution to thermal insulation although not long term. I might have to re-coat the roof next summer, but i am sure next time a single coat will do as weather shield itself should be durable.
Hope it will be beneficial to some of visitors here.
[This forum doesn't show pictures(you might have to copy & paste links in your browser. I have posted it another forum, if anyone needs the link, drop your email and i will send link.]