Have style and convenience
For respite from solar heat, either build with thick clay walls or create a void within the wall. Still better, try to build with hollow clay blocks
We can walk long miles under the hot sun, but cannot sit inside four closed walls for long; we can hold a lump of mud under the sun, but not even touch a lump of cement exposed to heat; and now the simplest example – we can hold a double-layered steel mug with steaming coffee, but not even touch it if it is the normal single-sheet type.
One can figure out what is being conveyed. Presence of air discourages the convection of temperature, mud and related earth products insulate heat and the gap between two layers of steel in the coffee cup reduces the transmission of heat from inside to outside.
What are the lessons to be learnt? For a respite from solar heat, either build with thick clay walls or create a void within the wall. Still better, try with clay and hollowness together, i.e. build with what we call as hollow clay blocks.
In short supply
These blocks were not available in Bangalore till about 20 years ago and even now are in short supply. Calicut, Mangalore, Kundapur, Huliyar, Kunigal and Tumkur are among the prominent places of their production, with minor cost variations.
Popular block size for load-bearing walls comes in 6”x8”x16”, with size variations in length and width being available. Being nearly seven times the size of a normal wire cut brick, the unit cost is cheaper, mortar consumption is reduced, wall weight is lessened and mud consumption at the factory is cut down.
Buildings gain most heat from the roof and then from walls, depending upon the direction they face.
We may orient the building such that the least of solar rays fall directly upon the walls, yet during the course of the day, some sunlight would fall directly on the wall. The resultant heat transfer to inside can be controlled by using hollow clay blocks, especially in south and west orientations.
These blocks have high density surface grain structure, and as such need no plastering to make them water proof. Being exposed, the house stands out in the residential block and becomes a landmark in a short period.
We not only save on plastering and painting costs during construction, but also save on life cycle costs since these walls need minimal maintenance.
Hollow clay walls define a different kind of aesthetic play, and many find it adorable. Let us understand more about building with them next week.