Try to shade the surface with wooden pallets, which is a frame of wood planks with gaps in between.
For reasons more than one, the summer season in India is a popular topic of discussion. It is possibly comparable to the British often talking about their rains.
Imagine the book titled ‘Indian Summer- Lutyens, Baker and Imperial Delhi’ which has little to do with climatic data on India, being the story of how New Delhi was planned and made, written by Robert Grant Irving. Another book by the same title ‘Indian Summer’ is on ‘The Secret History of the End of an Empire’ written by Alex von Tunzelmann, even more remotely connected to the idea of a season. Even the film ‘Heat and Dust’ directed by James Ivory attempts to refer to our summer, even if it is metaphorical. Summer is the talk of town.
Nowadays, Indian summer is in the headlines for the more direct climatic reasons – every year new records are being set for the highest temperature of the decade or so. How we the people and our consumptive patterns are among the creators of this record is rarely discussed, but the soaring temperatures are always debated intensely. As a fall out, sale of air conditioners is also soaring, paradoxically pushing the outdoor temperatures further up.
It appears like temperatures have crossed the limits of passive cooling and we have given up hopes on simple measures. Partly yes, but in many cities like Bengaluru which witness the extremes only for few weeks in an year, there is no real need to switch over to air conditioners. Shading the roof during the high summer can reduce indoor temperature to bearable levels, if not as low as AC can achieve.
Terrace gets direct solar incidence, hence has high solar heat gain, which is transferred to inside surface by conduction. Imagine we try to shade the surface with wooden pallets, which is a frame of wood planks with gaps in between, used in packaging especially across ships and such others. Google search can show up many images. Once unpacked, these are discarded for sale in the seconds market.
No heat transfer
Placed on the terrace, they let in direct light between the gaps for a short time span, which does not let the surface gain much heat. Of course, the air under pellet gets heated up but hot air moves out letting in cooler air from outside the pellet, so very little heat would transfer through convection.
These pellets, often made abroad with pine and such types of timber, can withstand sun and rain for a long period, if treated well. The gaps between them can be maintained fairly narrow; as such anyone can walk over them without any discomfort. In case of any unexpected summer showers, the rain water drains out without any hindrance. Once the scorching summer is over, the pellets can be safely stored for reuse the next season.
The theory behind this idea is rooted in a big sounding term ‘ventilated cavity roof’, but can be achieved in a small budget.