The Hindu, 15 de Agosto 2010
"Building with bricks is as universal as fabric in cotton. From the earliest times, human beings have experimented with soil to create shelters for themselves.
Soil was processed to get building mud, and dried under sun resulting in un-burnt mud blocks, fired up to get burnt bricks, which then evolved into better types like chamber and wire cut bricks.
India exhibits, historically and otherwise, a wide range of examples for brick structures.
In composite masonry walls, needless to say, bricks are among the most commonly used.
The outside demands burnt clay blocks or wire cut bricks with high surface density and resistance to wear and tear, while the inside could be the normal table molded bricks suited for plastered finish.
Granite stone, either as size stones or as slabs, is popular in composite walls along with bricks in the Bangalore context, both being local materials.
Just working with stone and brick, often keeping stone outside for elevation and then reversing it at other places, making it the internal wall is actually fun! The resulting external and internal patterning can be so interesting; no additional efforts would be called for to create the building elevation. Why are we repeatedly emphasizing on leaving the material exposed? It is not only to reduce heat gain, but equally well to reduce construction and maintenance costs.
People working with textiles can tell how cheap the basic cloth is and how finishing it demands money. Hence, using khadi or simple kora cloth is always an economical solution.
People working with clay can tell us the finishing like glazing and pattern making makes the pottery better, but costly as well.
It is true in building construction too where the finishing costs are double that of basic superstructure, hence our emphasis on leaving the material exposed.
Tied to each other
In a composite wall, the outer and inner layers need to be tied to each other by a single stone going through the thickness of wall or a small piece of reinforcement rod or there should be adequate randomness in the wall core such that two layers do not fall apart.
The course height would vary between stone and bricks, so only occasionally they both would be at same level, which is acceptable.
However, when they reach lintel or roof bottom, both the materials need to reach together.
It demands pre-checking the course height and the mortar joint thickness, adjusting it to match with levels as needed.
Periodic checking of levels with water tube levels is a simple measure to ensure quality of finish.
To maintain uniform joint thickness, a piece of wood of desired thickness could be used as a standard reference.
If both sides are to be exposed, the electric conduit pipe should be laid within the wall during construction itself!
Composite walls in stone and brick have great potential, but one precaution. Once done, there is no changing; hence we need to get it right the first time round itself.
Sathya Prakash Varanashi
(The author, a Bangalore-based architect, can be contacted at varanashi@gmail.com)"
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