Monthly Archives: April 2019
Though laying the foundation is the first task at site, it should be the last decision to be taken.
The most invisible, but critically important part of any building is the foundation. Incidentally, though it is the first task at site, it should be the last decision to be taken, after all the ideas about the superstructure of walls, voids, roofs and such others are finalised.
Traditionally, foundation meant only one option – dig into the ground, run a thicker and widening wall down under all along the wall. Even if the building were to have intermittent wooden pillars, arches or any other design feature, full-length wall foundation was mandatory. Possibly, the failure of earlier structures would have made people wiser, to evolve the load-bearing wall system.
The idea of isolated column foundations connected by beams at ground level was introduced when the RCC frame construction became popular, where we could save time and money by not digging into the earth all along the wall.
Locations with loose soil composition, water-logged sites, constructing along sloping grounds and such other contexts hugely benefited by the RCC column footings. The discovery of this frame construction system with plinth beam is gaining popularity even in rural areas today.
On the flip side, this system meant the total building be built with concrete columns and beams resulting in budget escalation, higher embodied energy consumption and the need for a technically better supervised project. On most occasions, for simple G+1 houses, RCC frame is simply unwanted, but adopted to hike project costs to financially benefit all in the team. RCC is also short lived, unsustainable and difficult to dispose upon demolition some day in the future.
Imagine a case where the conventional load-bearing wall foundation would have worked out costlier due to soil condition, which gets realised only after the earthwork excavation. Is there a way out to economise without compromising on the load bearing capacity of the foundation?
Structural engineer Ravindranath Bontadka came up with a curious solution for a house in Erode by merging the plinth beam concept with load-bearing wall.
Load points were located, masonry piers as if the house would have masonry columns was introduced and the top of these piers connected by plinth beam. Now, the house plinth is ready for its nominal one or two floor construction without any RCC columns, but has equivalent to column footings underneath built with conventional size stones.
Surplus mud dug out from foundation trench was used for making interlocking stabilised mud blocks, leading to a win-win situation. Of course, we need to seek expert advice before venturing into such hybrid concepts.
Eco-friendly and cost-effective architecture is not a one-stop solution to be applied all over the country, like the RCC frame and slab system. Everywhere we see the one and only type of building with columns and slabs cast, later covered with walls, be it on a hill slope or the seaside. It’s time to localise our actions.