Every child while reading history would have wondered how the pyramids were built, which even today are a construction wonder. The massive walls surrounding Egyptian temples had tapering stone walls, wide at the bottom and narrowing at the top, still standing after thousands of years. Classical temples of Greece continue to attract visitors from world over even now. Many Indian forts continue to be impregnable since they were built. If someone tells us that majority of these were built without any mortars in their joints, can we believe it?
The idea of mortars comes much later in the history of settlements. For a long time, humans built thick walls just by piling up stones one above the other, made mud balls rolled into a wall using mud slurry or built mud walls layer by layer. They behaved like a homogenous element, staying strong by the sheer mass. In many regions, timber boards became house partitions or shelters were made with bamboo, grass, mud paste and thatch which required neither mortars nor joints.
As the walls became thinner, especially built with masonry, lateral stability was provided by joints packed with mud. As time progressed, mud was made stronger with lime content; hence many monuments show melted brick surfaces, but lime mortar joints still holding them strong. For over 50 years now, cement mortar has been gradually replacing the earlier options. If our ancestors could build without mortars, why can’t we do so today?
Technically called dry masonry, placing thin stone slabs in mortar-less stable joints can still be seen in areas where they are locally available in plenty. The stone surfaces are dressed to hold on to each other. Unfortunately, the economically weaker section use them more often, hence the formal constructions relegate them to the backseat. Rammed earth walls, achieved by ramming pre-mixed stabilised mud between side supports, is slowly but steadily reviving.
Avoiding or reducing mortars means lesser consumption, zero wastage, faster construction and better aesthetics. Most often, justification for plastering and painting the wall comes from the fear of water seepage through the joints and the ugly looks of mortared wall. We make the walls too thin and then spend on these avoidable applications.
Avoiding joint mortars is not a new thought, for there have been many attempts to avoid them. The more successful ones have led to interlocking masonry blocks, both for wall and floor applications. Mud, laterite, fly ash and cement aggregates-based, machine-pressed blocks are out in the market for a while now. The term ‘paper joint’ is in circulation, mainly in the domain of floor slabs and wall tiles, denoting a joint so thin it does not need any mortars.
More recently, we have been seeing adhesive- and polymer-based dry fixing solutions like the one introduced by Wienerberger company. They may not avoid a joint, but may replace the idea of cement mortar by another futuristic material. We need many such solutions.
(The writer is an architect working for eco-friendly designs and can be contacted at varanashi@gmail.com)
