Monthly Archives: October 2014
There is something interesting about how birds and flying insects create shelter. They rarely use living matter! Most birds make nests with dried twigs and fallen feathers; honey bees do not use any outside material; wasps build with mud; beetles live in holes dug into dried up trees and the story can go on.
Most animals neither use fresh materials for sheltering themselves nor do they produce waste during the making of the shelter. We of course continue to ignore the waste, instead produce waste during sheltering ourselves.
Even today, we see the economically weak people create city shelters using discarded materials such as film posters, wood from container boxes, coconut leaves, used tin sheets, tree branches and flex banners. It is not that everyone should build such slum-like houses, but realise that humans are still capable of finding ways to turn the discarded into designs, which we mostly ignore. Especially, in a professionally made structure with architects and engineers, it’s all formal architecture.
There are exceptions like the Manav Sadhana Centre in Ahmedabad by architect Yatin Pandya, a multiple award winning project evolved around and with waste materials such as plastic bottles filled with mud, glass bottles embedded into walls and ceilings, wooden crates resized and refitted, and broken ceramic brought together in varied patterns. It could be among the best examples in India for designing with the discarded.
Among the easier systems doable in any city is the wall with glass bottles. Collect bottles of preferably same type, choose the sides and build with rich mortar as a non-load bearing wall. Slippage due to bad bonding and cracks between the two materials are the only two major problems here that can be easily solved. A more advanced application is to cast the bottles as panels, by keeping them in a mold with required spacing and then concrete poured around to get the pre-cast element. Spacing can be deliberately varied to create interest, but verticality of the wall is important.
Electrical conduits cannot be embedded within the wall, so have to be outside the surface or better avoided on such walls. External waterproofing needs to be done with approved liquid applications, with plastering and painting costs saved upon. The bottle wall provides light without glare and heat.
Historically people built with locally available unwanted materials much more than today. Nowadays, manufacturing the new product is so dominating, even the idea of recycling waste into a house will not be to the liking of most people. The exception could be with antique doors, windows and pillars which are still accepted by the discerning when they get a building done.
Building with waste is surely an extreme approach towards sustainability and the ideas may not be best suited for all contexts. However, every such alternative idea will have some most suited contexts also. Then, we need to think of waste.
Possibly no animal on this planet can change its habitats and habits of shelter making as humans do, a fact that can be corroborated by hundreds of examples including the famous nests of weaver birds, which have been weaved for many millennia, unchanged.
A small case in point is the wall niches. Found in all buildings all over India, the small depression within the thickness of the wall served as a handy place to temporarily keep household items. When placed outside flanking the main door, they lit up the entrance, both functionally and religiously.
In drawing rooms they facilitated craft displays, in the bedrooms knick-knacks were kept there, in bathrooms they became soap trays and in kitchens, all kinds of things could be found there. Of course, sometimes they could appear ugly, but equally well, they were adorned with art objects to the delight of the guests.
Not ideal in two places
Today, we hardly find these little cute niches and not many logical reasons can be extended to their gradual disappearance. Of course, there are some basics to follow if one intends to have niches.
They are not ideal in two places – on the external wall where the wall is not thick enough to take the depth and in toilet walls which are difficult to tile and maintain dry.
In internal walls, simply leave an opening in the wall, finish one side with chicken mesh plaster or the masonry that goes with the composite wall. A niche may restrict space usage in its front by negating the possibilities of shelves and furniture, but there are many walls which do not take an activity right in front.
Also, along passages, movement areas, walls edging a staircase and passive corners, niches are eminently possible to create a visual appeal and brighten up an otherwise dull corner.
A niche need not be a functional hole in the wall, but can be a piece of beauty by itself. Imagine it with a small arch on top or highlighted by different materials like coloured stone.
Most people prefer it to be around 6 inch deep and up to 2 feet tall, though some house owners like it to be bigger to house larger items for display.
Alternatively, a larger niche can also get subdivisions in between. Considering these are narrow openings, the top need not get a concrete lintel, but keeping a stone across, normal brick course on temporary support or two rods atop suffices. In case of a niche wider than two feet, concrete lintel may be considered.
Today, externally mounted, costlier and convincingly marketed option of plastic or wooden cabinets seem to be everywhere.
It’s time to revive the cheaper and easier solution called niche, built integrally into the wall.
Alternative construction ideas, such as concrete filler slab roof with cement blocks, can be applied where possible.
It feels good to read about radical alternative ideas in the Green Sense column, but how many of us can execute these in our own projects? Even if the owners are interested, the numbers could be very small given the unwilling builders, lack of materials, apprehensive masons or the fear of the risks involved. Each of the ideas written about in this weekly column since May 2010 is proven, in some project of this author, but a guaranteed performance alone cannot mean it will become popular.
Certain construction practices tend to replicate repeatedly, such that they form the mass of what we could call as the conventional. It is not always possible or desirable to replace mainstream ideas with alternatives, yet the spirit of the alternative can be applied where possible. Concrete filler slab roof with cement blocks can be a case in point.
One of the ideas behind the filler slab is reduction in the quantity of concrete, besides passive cooling, cost cutting and light weight construction. However, we need not discard the idea just because a clay ceiling block or Mangalore tile is not available. In most towns across India, cement blocks are available, both in hollow and solid models. Depending upon the slab thickness, an appropriate cement block of fitting size can be placed in between the reinforcement rods, before concreting. Of course, the spacing of rods and design of the roof have to be done by qualified engineers to ensure the roof is cast as per standards. The cement block is much cheaper, lighter and ecologically better than concrete, even though both are made from the same sources.
Nowadays, we get improved versions of cement blocks called autoclaved aerated concrete (AAC), which are light weight thanks to a porous cellular structure. Locally, they could be called as aerocon or siporex blocks. Compared to normal cement blocks, autoclaved blocks have nearly one-third density, but act as better thermal insulators and sound barriers and are water proof. They may not have low embodied energy due to the production technology and centralised factory with long distance marketing, but the fact that they replace an equivalent volume of regular rich concrete itself becomes a eco-friendly and non-conventional approach.
Autoclave blocks come in long sizes, so we need to cut them into three parts to get 8-inch long pieces, to perfectly fit within the spacing of steel rods. Once placed, they tend to shift when workers move around, so a small quantity of mortar can be poured into the gaps to stabilise them. This should not cover up the steel reinforcement. Electrical conduits and openings for fan box and such others can be placed by cutting any block as needed.
Small changes like replacing concrete with autoclaved cement block may appear insignificant, but many such small ideas together would lead to major impacts. We may stick to conventional ideas, yet express our concerns for the environment.