Monthly Archives: March 2015
Cement deteriorates with age, and has an inherent weakness of cracking.
How many of us know that India is the second largest manufacturer of cement in the world with more than 360 million tonne annual capacity? Is it a matter to be proud of? Majority will say, yes. The price of cement has come to indicate the health of market economy, shifting directions of monetary investments, rate of infrastructure development and such others. Again, an important information for all of us.
How many of us know that every tonne of cement produced causes nearly another tonne of carbon dioxide, a major contributor to greenhouse gases? Is it a matter to be proud of? This time hopefully, majority will say ‘no.’ This is besides the fact that cement also has very high embodied energy, a major concern today in sustainable buildings. If so, how should we treat this wonder material?
Cement is a product of calcium, aluminium, silicon and iron, supplied through mainly limestone, clay and sand. The mix in right proportion with more than 3/4th limestone is grinded, pre-heated and then heated up to 1400 degree centigrade in a rotating furnace kiln, where decarbonation takes place, releasing carbon dioxide, slurry and clinkers. The clinkers are set into a horizontal chamber for final and fine grinding.
Within about 200 years of its discovery, cement has conquered the world of construction, due to its versatility of usage, flexibility in design applications, strength and setting time.
While professionals may handle it more efficiently, even a village mason picks up the skills of working with cement very fast, hence its popularity. However, thanks to its popularity, we appear to be ignoring its drawbacks.
Though lime and cement share common raw material, cement deteriorates with age, while lime stays fit for long. Cement has an inherent weakness of cracking, passing on this trait to concrete too. As such, experts do not guarantee a cement and concrete building to last more than 60 to 80 years without periodic improvements.
Besides, it absorbs heat if directly exposed to sun, with surface cracks. If we checkout any building with only cement mortar plastering without wall paint, hundreds of cracks can be seen on the surface. Normal mortar tends to absorb water, being groscopic in nature, hence requires varied water-proofing applications. Traditional buildings in stone, wood, non-homogeneous roofs and such others could withstand minor settlement in site or even small-scale earthquakes. In contrast, cement as a material is not good to withstand settlements.
Despite knowing about the drawbacks of cement, we end up having cement mortar in all joints and surfaces; concrete in foundation, columns, lintels, beams, slabs, frames and coping bands; cement blocks in walls. What we are building today appears to be a cement building from head to toe.
While it is a dangerous trend in construction, it is equally a shame on us to neglect dozens of appropriate materials available to us. Once cement was a boon, today it may not be. It is time to look outside cement.
The basement has many functional advantages but the planning has to be early and perfect.
European nations adapted it long before we discovered its advantages, mainly due to their climatic zoning and multi-use potentials, but now its time every city home in India considers it as an option.
There is a flip side to having a basement, water seepage being among the greatest worries. It is possible to make it water proof by using concrete walls, external plastering with water proof admixtures and such others. Yet, most people fear the seepage and just do not build the basement at all. The other bothersome issue could be the raised ground floor, necessitated due to basement ventilators. As such, everyone needs to climb up by 4 to 5 feet while in a normal house we need to walk up by 1’ 6” only.
The major criteria towards building the basement should be the family lifestyle, for an unused basement is a waste of resources and money. Of course we are not discussing basement for car parking, which lacks efficiency, but may check out if activities like home office, extra storage, home gym, home theatre, drying clothes, family entertainment like TT table, community music sessions, dance classes and such others could be accommodated there. These tasks done elsewhere would consume more precious upper floors and negate the options for other uses.
Providing basement fully below the ground floor is ideal from the cost and construction criteria, but if it is not needed, we may consider part basements. In such a case, the area with basement below gets raised up, while the rest of house can be at normal ground level, creating a split-level house. Alternatively, we may also raise the areas without basement by filling earth, thereby bringing the whole house to the same level everywhere. While the split-level house appears nice, it will affect movement of babies and elders. Levelling the house will cost extra money, though it could be worth it considering the advantages of a floor in the same level.
Reduced climbing to reach the listed needs is among the main advantages of a basement, which is just one floor below the ground floor. Alternatively, the needs may end up on the second floor where people have lesser urge to climb or may hesitate to walk the guests up through the house, thereby reducing the frequency of usage. If we consider that basements cost less than upper floors both during and after construction, they come as a cost-effective solution. These part-underground spaces are cooler than the rest of the house, hence can be appropriate for specific usages.
Basements come with functional, economical and ecological advantages. More importantly, it is always a ‘now or never’ decision. If the basement is not done in the beginning, it cannot be added later.
Basement car parking holds more disadvantages than advantages.
Energy-efficient architecture revolves around not only technology and materials, but equally around the functional benefits we gain across time from the design details. After all, every square foot of built-up space costs time, money and effort, hence it is important to check the implications of our ideas and decisions, to choose the most effective solution among the available options.
Accommodating car parking in a typical house site could be a good example to elaborate this point. Strangely, majority of people believe parking the car in the basement saves space, while the truth is it consumes double the space which is actually required! The ramp down to a 5 ft. lower basement needs to be around 25 to 30 ft. long for a comfortable drive, while the car itself will not be longer than 16 ft. long. So, just imagine the total length of 40 to 45 ft. we spare to park one car, which on normal ground level would not demand more than 20 ft.
Sometimes, people try steep slope to save space, which is difficult to drive in and out. Now if we look at the extra cost of executing the ramp, making it skid proof and building up the side retaining walls, the logic of ground-level parking sounds attractive.
The ramp space cannot be used for anything else but driving down, unlike the flat part of the site. On ground, if the car were to be kept out temporarily, the space could also be used as a guest space during events, buffet lunch area, kids’ play area or shaded area for plants. The sloping ramp, besides not offering any other use, also divides the ground space available into two parts which further reduces the multi-functionality of the site.
During monsoon, ramps collect water flowing down onto the basement floor, necessitating a sewage on-line pump for emergency pumping out.
Meaningfully accommodating the car parking area has been among the challenges for designers. Front garages prove this point with their limited range of unattractive rolling shutters while the ramps are even more difficult. Ramp going down the ground level, with a shutter at the entry to basement, can be an equally challenging task in developing an attractive elevation.
If parking is on ground level, the car can be placed up to the edge of the property, whereas a ramp can happen leaving the setback. This setback space gets cut off from the rest of the site, rendering it nearly useless. Even to access this area, we need to cross the ramp.
This analysis is not to negate the idea of a basement, but to discourage car parking in the basement. If we analyse expenses, advantages and disadvantages of basement car parking, we see more disadvantages than advantages. Equally well, this analysis is to suggest a methodology to be adapted when we design green buildings, where we may weigh the options for their real benefits and get an efficient building.
Exploring alternatives is mandatory if we want a greener future.
How did people get hot water before the electric geyser was introduced? They simply heated it with firewood and even today it is the most common approach in all rural areas. How do we heat water for drinking? The burning gas stove ensures we get healthy warm water to drink. The above examples are only to say that heating is not solely dependent upon electric geysers.
The idea of wood fired hot water still continues, often called in Karnataka as Gujarath boiler, an idea that possibly originated from industrial boilers. It consists of an oven with a small mouth and a water pipe with cold water inlet at the bottom. This water pipe rises upwards, initially with wider diameter like 12 inches and later narrowing, reaching up to the last terrace without any other joints. From this highest point, the pipe comes down to the bathrooms as may be needed, creating a completely sealed pipe system. It is important that the system works like one unit, with no openings except for one inlet and outlets.
Any combustible material like home garden wastes, coconut peels, dried twigs, leaves, paper and old trash, most of which can be found in any city, can be used as a replacement for firewood in the oven. The cold water filled in the pipe gets heated up, rises up thanks to differential weight of cold and hot water and reaches the terrace level while fresh cold water flows to get heated up. From the terrace level, the hot water flows down into bath taps by gravity. As we use the hot water, the outflow is replaced by fresh inflow of water and after a few people taking bath, there may be no more hot water left, suggesting we fire it again. Gujarat boilers are among the easy solutions providing life-long service with a water column, simple operation and short firing period with very little running costs.
Cooking gas cylinders have revolutionised not only the kitchen but also the bathroom. Popularly called as gas geysers, these battery operated geysers are very economical and convenient. Just like in a gas stove, an inbuilt lighter starts a fire inside the geyser, heating up the water in the small storage tank inside to provide hot water instantly. As hot water flows out, cold water gets in for further heating.
There have been rumours about them as being unsafe which has no proof, especially when the gas cylinder is kept outside the house. Operationally, it’s same as the kitchen stove, but for the periodic need to replace batteries which light up the spark. The unsafe ones are the water drums with exposed electric coil immersed inside to heat water.
With our modern lifestyle already in place, there are no single and perfect solutions to our needs today. Exploring the alternatives is hence mandatory if we have look for greener futures.