You have got a few options.
- Perhaps most effective yet most complicated is installing insulation sheets such as offered by Jumbolon from Diamond foam bananay walay. They offer complete solutions including designing, manufacturing and installation of heat proof systems. However, personally I don't recommend such things as a civil engineer since our local labour isn't very good at handling such complicated materials. Even a minor crack in the top concrete layer above jumbolon sheets will play havoc with your roof. Just a minor seepage is a big pain in the neck even in the simplest roof slab.
- You can also install special roofing tiles. They allow a gap between the existing slab. I’ve seen such tiles in around pindora, Rwp a few years ago. But not sure how good they are but its not so easy to have this system trouble free for a long time.
Some of the alternate, quicker solutions, which may have limited insulation capabilities but more practical are:
- False ceiling inside your home. That will help reduce some heat coming from the roof.
- If your roof is not lined with terrazzo flooring (in local lingo we call it chips), do that with higher density of marble chips along with white cement. This way, your roof will appear almost white reflecting most of the sunlight and reducing the heat.
- You can also cover your roof with white or silver sheet as BTCF has suggested above. You can use green cover made of synthetic material, I’m forgetting its name though. Its quite common.
You can use all of the above alternate solutions simultaneously to get a better results.
The best time for heat insulation is when you are constructing your new house. Installation of heatproofing systems as retrofits is bound to give you a big headache, sooner or later in our local conditions.
In the end, I feel really bad at our lack of research in construction industry about various materials and construction methodologies in the building construction. One reason is that our approach in general is driven by the economic reasons. We usually overlook the operational costs and comfort in favor of lower construction costs. The little research in the engineering universities stays there and no one tries to hook up such a research with the local construction industry.
