Monthly Archives: December 2013
Imagine we run a public survey on what do people think about building contractors and what results we can expect. To our surprise, majority may say that contractors are not honest. It can be very hurting for any professional group to get such a rating, for most contractors working on private buildings are actually honest. Somehow, the word contractor has been projected in a negative light, despite many of them being good.
Equally well, the contractors feel the owners may not keep up to their words at the end, raising unreasonable objections about time, quality or the finish, hence they try safeguarding their interests in a subtle way. Contractual systems have evolved partly because of such lack of mutual trust. In labour contract, the owners try an upper hand by controlling materials, while in lump sum, builders gain superiority by minimizing the role of the owners.
People, who felt shortcomings in both, have sought another system called supervision contract. All the costs of material and labour are directly paid by the owner, while the role of the contractors is restricted to instruction, supervision and coordination. They may also help the owner in procuring the materials and measurements, against which they get a percentage of total cost. The owner feels confident about the money outflow and choice of materials, while the contractors feel secure about their income. Though it appears to blend the best of labour and lump sum, it suffers from low degree of commitments from the construction team; less control on minimizing wastage and least control on total project cost.
By far the best system of contracting, also called as item rate contract, refers to the builder being in full charge of the project. As such, there is a single person to inform, instruct and coordinate, which avoids all blame games and conflict of roles. Construction costs are not mentioned separately for materials or labour, but together for an item of work like wall, plastering, railing or water proofing. This would include the cost of material, transportation, wastage, labour, overheads, profits and such others together.
There would be a pre-construction document called Schedule of Quantities prepared by a quantity survey engineer, listing all tasks and quantities, against which the builder quotes the prices for mutual agreement. As the work goes on, bills would be submitted for satisfactorily completed works to be check measured at site by the engineer, certifying for payment by the owner. This system is transparent with every item stated, yet flexible where any material can be changed by changing the rates accordingly. Modes of checking every cost ensures honesty in execution. The owner, designer and the builder can work together without conflicting roles.
Alternate eco-friendly ideas need to evolve with the project to ensure win-win situation for everyone in the construction team. They can not easily fit into the convention contractual systems. The best option is to trust each other and go ahead with the total contract.
India is often referred to as a land of great ideas, with the majority of them unimplemented. Construction field is slightly better off with only implementable and mutually agreed concepts getting drafted, hence built as well. However the advent of green ideas and stress on sustainable construction has focused lime light on varied innovative ideas, often found only in essays, research papers and seminars. Designers and thinkers have done their job, with shortage of builders and workers to get them executed at site.
No wonder, this Green Sense column has elicited many mail responses seeking advice about contractors who could build the new or countering technical experts who speak against the alternate. The experience of the majority of owners has been the same – building green sense is an enormous task, unless we get the right kind of people.
Traditionally we are used to a contractual system called labour contract where the owner supplies and pays for all the materials, while a head mason supplies all the workers, besides supervising their work. Such teams will simply do what the owner wants, hence superficially appear capable of building eco-ideas. However majority of labour teams have no idea of the alternate and owners despite reading essays may not be technically qualified to instruct the team or may not have the time to spend on construction site.
No one would like their building project to be an experimental learning for an untrained team, wasting time and money with no guarantee for assured product. Invariably, the green intentions slowly get dropped off, in favour of conventional approaches, simply because the labour contractor is more confident about repeating what the team as done in the past.
Lump sum contract
Another popular contractual method has been where a professional contractor charges fixed lump sum money for unit area, most common reference being rupees per 100 sft. of built area. It is an all inclusive cost once the construction system and materials are mutually finalized. Technical experts like qualified engineers and architects could also be involved here, primarily as advisors. By far it is the most hassle free system, where the owner can relax and one day just walk into the building, though there may be no guarantee for quality or time for evolving customized designs. From an eco-building perspective, the major limitations here are rooted in its rigidity. Once the price is fixed, material variations become bone of contentions and substandard quality becomes a cause for difference of opinions. Lump sum contractors charge very competitive rates based on standard construction practices to survive in the market, hence prefer to work on routine projects with least of fresh instructions to their team, ensuring no loss in the income. As such, majority of them refuse to undertake buildings with alternate ideas, with the apprehension of losing money at the end.
So, are we the end of the road? No way – there are alternate modes of getting alternate ideas executed that we can explore.
Today everyone is chanting the mantra of green – in environment, agriculture, architecture or products. However knowing how subjective we can be on our opinions and argue in favour of our personal ideas, how do we ensure that we all agree on what green means? Without a commonly understood and agreed upon criteria for identifying the green, say in building materials, we will not be able to converge on a larger agenda of sustainable buildings.
Many institutions have strived towards defining the characteristics of materials, mainly Bureau of Indian Standards (BIS), The Energy and Resource Institute (TERI), Indian Green Building Council (IGBC) to name a few. Considering that many experts have worked for years to arrive at the norms for assessing building materials, the standards stated by these have come to stay as yardsticks for today. In an over simplified manner, the following are the major parameters.
The value point
Among the important criteria is the R value, a figure that suggests the thermal resistance of a material to conduction of heat from outside to inside through the material. Naturally, the thicker it is lesser heat gets transferred, keeping the indoors cooler by passive means. Here lies the secret of traditional buildings being cool, with massive walls and thick roof! Also, if the material is hollow inside or low density, it offers greater resistance. However, if it the material is dense and heavy, more heat gets transmitted.
The next criteria U value is directly related to the R value, a number that refers to the rate of heat transmitted in a unit area. The figure may from o to 1, depending upon the quantity of heat transmitted. Of course the extreme figures refer to none of heat or all of heat getting conducted may be rare, with most cases reporting in the mid range.
A related term is thermal mass – the nature of the material to act like a store house of temperature, in a way balancing the outside and inside variations in temperature. All masonry walls have good thermal mass behaviour keeping cool summers and warm winters, while transparent materials like glass are of low efficiency.
Raw material saved is an important criterion, mostly ignored at present. It could be in the manufacture of a material or its usage in construction. Nowadays many alternate options for producing cement is being discussed to make the process more effective. Reference construction, if thicker bricks are used reducing the mortar joints, there will be saving in mortar for the joints. Interlocking joints with no mortar have also proved to be possible. Like wise, how much waste the material generates either during manufacture or during construction is also a major consideration in assessing a green material. To illustrate, glass has high waste production, so reusing broken glasses is being encouraged in the production of new glass itself. There are more criteria to assess the materials that could be looked into.
Increasing numbers of social thinkers are writing today about how we are living in a materialistic world, suggesting consumption and depletion of resources. By gentle twist of words, we can also say that we are living in a material world, with maddening choice of materials. Selecting and shopping what we need is no more a simple task, but demands researching and rejecting among the options. The idea of selection would vary case by case, with eco-friendly construction having its own set of criteria. Over the decades, specific qualitative and quantitative standards have been evolved to judge and classify materials under the green category.
In principle, all the building materials come under 3 categories – natural, processed and manufactured. Mud, wood, stone, sand, slates, lime, bamboo, rattan, thatch and such others which we use mostly in their natural state with minimum re-sizing come under the natural category. Even today, these materials dominate the larger building stock of the world and are among the best choices towards a sustainable future. However, if they can meet the quantitative demand for materials in this ever expanding urbanization is a matter of debate. Also, while items like wood are renewable sources, few of them like stone are exhaustible. Much of contemporary architecture of today can not be achieved only by natural materials. Notwithstanding these counter positions, we may safely assume that using natural materials compliments our objectives of sustaining the Earth resources – an option with least energy consumption, minimum procurement wastage and negligible residual wastage.
The next category called processed materials suggests an altered state of the material, process itself ranging from the basic to the advanced. Village brick making with firewood alters the raw clay into burnt bricks permanently altering the characteristics of mud, hence can be called as processed material. So are products from iron ore, paints from vegetable dyes, pottery from clay and tying ropes from natural fibers. They consume some energy and produce some waste, but get customized for the intended use, hence become more efficient than being in the original state. Like the natural category, the processed items also lead to depletion of natural resources, hence judicious degree of processing and usage may balance their adverse effects.
The worst kind that leads to maximum resource consumption, waste generation and energy requirement are the third kind – manufactured materials. Excepting some raw materials used in the production process, much happens through chemicals and artificial means to bring a new material to the earth. The high ended industrial process not only demands skill, but also wide spread marketing to make the production financially profiting, a goal normally fulfilled by the market economy. The artificiality of the material ensures, the raw materials used never get to return to earth and regenerate. Popular items of today including steel, cement, glass, aluminum, plastics, construction chemicals, vitrified tiles, adhesives, insulation items and many more of them are flooding the building scene today.
No wonder, the green house gas emission from building industry has been on raise – a matter to be taken more deeply.