For construction of a building whether small or big, there are certain parameter which are required to be adhered to, to meet the proper designing, various materials required for construction including wood-work, electrical work, plumbing work till finishing with paints and polishes.  To sum up, for co-ordination of all these activities a builder/ owner executes an agreement with the contractors/ experts of different field for timely completion of his project .
the details of various contractors are given as under.

      1. Appointment of an Architect.
the main work of an architect is to ensure that the construction of a building is done strictly as per the approved layout plan of the building and also ensure that all bye-laws including safety parameters are properly complied.

      2. Construction Contractor.
As all are aware that contractors are basically those people who work on the basis of a contract, which is usually time-bound or more specifically speaking project bound in terms of construction assignments. While most of these professionals are involved in the tasks during the construction process, there are others who sign an extended contract of tending to the structure or building in terms of maintenance and repair work after the construction activity is completed.
these people who take constructional contractual work need not be formally trained in their field of specialization. their main role is to supervise the manpower in their area of service provision as well as source out supplies of the raw material. they conduct extensive market survey in their area of specialization and can help in purchasing material of various grades and costs, depending on the budget decided by the owner.

     3. Carpentry Contractor.
While the interior designers and architects know how they want to use the space given to them, the carpentry contractors help them in terms of the kind of furniture that can be used. It is not necessary that wood is the only requirement in terms of the furniture; they could fit in stainless steel or aluminum furniture too. Especially since these metals are available in attractive finishes and have a longer lifespan than wood they are preferred for office interiors.

the carpentry contractors may take up the contract to work with the designers only till the completion of the project, or they may enter into an extended contract whereby they look into maintenance and repair work of all furniture and fixtures. this would include timely polishing and cleaning, whereby they enter into a sub-contract with pest-control contractors. this extended contract is usually between the occupant and the contractor.

     4. Plumbing Contractor.
Plumbing contractors work along with the civil engineers and structural engineers looking into the actual labor work involved in plumbing. Many people understand plumbing be fixing of all kitchen and bathroom problems with regards to drainage and piping. this is one of the aspects of the plumbing job, but their main task begins with laying down the drainage system of the structure when being constructed. these contractors are involved in the construction process as and when the first foundation block is laid.

While the engineers design the entire drainage system for the structure, the plumbing contractors handle the manpower and sourcing of the raw material. they are well informed about the different types of piping material and other tools required. they understand the difference in the varied methods of laying down pipes of different metals. In fact their understanding of the structures drainage system is far more in detail than that of the engineers, because during times of repair work, they know where exactly the problem is and so instead of causing additional damage to the structure, they dig in the right point.

     5. Roofing Contractor.
What is a structure or building without a roof? In fact if the foundation is an important aspect of every construction, so is its roofing. Many structures and buildings have known to collapse because of unstable roofing. this maybe the uppermost rooftop or then the intermediary roofs of every apartment or office within the structure or building.

Roofing contractors are responsible for the physical task of pulling up the roof. they generally work with the structural and civil engineers when deciding the material to be used for the roofing of the structure. they also are consulted by the architects when designing the rooftop. Apart from the basic construction, they are also aware of all material and handiwork required for creating aesthetic false ceilings, without endangering the structure and lives of the occupants.

these contractors have an important task at hand and their laborers' job is risky. In fact in the case of multi-storey structures, every roof they construct becomes a floor for another apartment. these have to be strong and the raw material they use should withstand any kind of artificial or natural trauma.

     6. Steel Contractor.
Steel contractors are mainly hired since they specialize in steel-ware that is required in the construction activity. they not only know from where to source out the steel requirements, but also every aspect of fixing them together. they usually have a team of laborers who have a specialized acumen in putting together steel parts in constructions.

Stainless steel is the most preferred metal in the construction business. this is more so because of its resistance to corrosion and staining that usually make metals weak. this metal also requires minimal maintenance and is relatively cheaper than the other metals. In fact a lot of aesthetically designed structures have unique rooftops designed out of stainless steel.

the steel contractors usually work with the architect and structural engineer. they are aware of the steel market and know from where to get all requirements such as steel piping, sheets, fixtures, etc. they are also of help to the civil engineers and supervise the task force involved in laying down or fixing up the steel products.

     7. Electrical Contractor.
While the electrical engineers are involved in planning and designing of the entire electrical layout for a structure of building under construction, their task can only be completed when they work along with electrical contractors. these professionals work on a contractual basis for various construction works. they are responsible for looking into the physical activities of electrical layout.

the electrical contractors bring together the work force consisting of unskilled laborers who are capable of functioning as electricians. Apart from supervising these laborers, the contractors also look into the day-to-day expenses in this department in terms of requirements and wages. they also help the electrical engineers in seeking required state and government permissions to have electricity transmitted to the structure or building being constructed.

     8. Painting Contractor.
the beauty of every constructed structure and building lies in its exteriors. Apart from a strong foundation and aesthetically designed structure, the painting work adds immense value to the construction. In fact selecting the right paint in India is a slightly difficult task, especially because of the monsoons that is a beautiful season but tends to make the paint drip away; and rather than leaving the building looking washed and clean the rains make it look dirty as if in urgent need to be painted all over again.

Painting contractors are of much needed help when it comes to paint selection. the fact is that certain companies do manufacture waterproof paints, but then the shades and colors are limited. And if the architect is looking for colors that are not treated to waterproofing then by the end of the monsoons it would not look like a new structure or building.  Now-a-days state-of-the-art exterior finishing are available which are installed for lifetime of a building and gives very rich look.

     9. General Contractor.
A large number of general contractors work on handling the labor force and can supervise any kind of activities. they are capable of coordinating between the various units involved in the constructional activity. Some of them take care of general aspects of furniture and fixtures and other accessories.
To describe them, they specialize in multi-purpose activities. Usually general contractors work on large-scale projects that are sanctioned by the government. In India, in order to get a governmental project one has to give all details and apply for a tender. If it is sanctioned in their favor then they can take it up. these include road works, construction of bridges and railways, etc.

     10. Landscape Contractor.
the landscape architects and environmental engineers work on ways that they can improve the environmental conditions. they attempt to create green zones in the city, wherever they can. they design various gardens, parks, approach roadways to structures, etc., that are required to provide a pure breathing surrounding for the occupants. they both would have developed well-founded knowledge about the various types of plants and trees that could be planted in various areas, but the actually manual work would be done by the unskilled labor.
Apart from putting a team together and supervising their activities, landscape contractors also take the responsibility of sourcing out & purchasing seeds and saplings. they also take the responsibility of purchasing the tools required in creating patches of greenery.

     11. Masonry Contractor.
Sourcing and assembling basic constructional material such as stones, concrete, cement, bricks, etc., is assigned to masonry contractors. these contractors are aware of every detail of the masonry market, whether it is the raw products or the ready to assemble goods, as well as the manpower.
Bricks, cement, concrete, stones and other building material determine the life of the building. the quality of these products has to be the best and strong enough to withstand any kind of weather. For instance in India, maximum damage to property occurs in the monsoon season and all building material should be able to withstand the heavy rains. the masonry contractor is responsible for the quality check and can be held responsible if any disaster occurs due to adulterated building material.

     12. Mechanical Contractor.
Mechanical contractors generally sign up contracts with various industrial set ups belonging to the private and public sectors, as well as other governmental agencies such as the defense services, wherein they take care of all mechanical problems that may occur.

Apart from having a team of mechanical engineers, they also coordinate unskilled laborers who are trained to operate machines in mills and factories. these contractors basically specialize in the area of mechanics and machines.