The Building Construction process varies from one structure to another, based on requirements, size, the complexity of structure, building function, building materials, and execution of the project.
There are few other factors, such as soil type, weather conditions, construction material availability, availability of local skilled and unskilled workers, and sufficient construction tools to execute the project. These factors would affect the building construction process.
How Building Construction Process Works?
Generally, the building construction process is divided into two major activities group known as;
- Pre-contract activities
- Post-contract activities.
Pre-contract activities refer to the activities prior to the commencement of construction work. In contrast, Post-contract activities are activities after the contract is finalized. In this article, we discuss the building construction process based on the two activities stated above.
The list of pre-contract activities of the building construction process is as under;
- Project Location
- Building Planning
- Soil investigation report
- Building Design
- Estimation and Budget
- Building permit
- Assign a Contractor
The project location is the most important and deciding factor in the construction of any building. If the building project is private, it should fulfill the basic needs of residents and living necessities such as the availability of public services, road, and transportation, in case, the project is government-funded and is constructed for the public, the concerned authorities must ensure the project will be utilized by the vast majority of the public in the surroundings.
Once the location of the building is specified, the second step is to plan the building by the architectural engineers based on the requirements of private or government entities. Architectural engineers normally act as project consultants as well. A consultant is required on the project to maintain the working relationship between client and contractor. and responsible for maintaining the work quality and obtaining the authority approvals.
Soil Investigation Report
The soil investigation report is prepared by a geotechnical engineer before the design of the building structure. It is mandatory for structural engineers to know the soil properties in the construction site. The structural engineer is responsible for designing the building structure according to the soil bearing capacity. The soil investigation report is based on the investigation of the survey team and contains soil properties, types of soils, the load-bearing capacity of the soil, etc.
After the building plan and soil investigation report are submitted to a structural engineer. The structural engineers instigate the design process and the type of foundation is determined and designed. A load of the superstructure and the soil bearing capacity plays a major role in the building design process.
Estimation and Budget
Once all the design is finalized the cost estimation engineer prepares the bill of quantities (BOQ). BOQ is the estimated material quantity, cost, for the number of different items and works. If there is a tendering process required, the estimation engineer prepares a BOQ with quantity and rates columns, the rate columns should be filled out by the contractor and submitted to the Client.
The consultant is responsible to get the building permit from the concerned city development authorities. Obtaining a building permit may require certain documentation such as a soil investigation report, building structural and architectural drawings, land survey, and structural report. Once the building permit is approved, the authorities may request to appoint a contractor to execute the job.
Assign a Contractor
Assigning a contractor is significant and essential for the timely completion of the building project. All the project details shall be prepared by the project consultant and clearly described in the project specification and contract document. The terms and conditions of the contract should be thoroughly checked and signed by all parties related to the project. This is a very important factor in the building construction process and must be handled by an experienced technical person.
Post Contract activities are the second type of activities of the building construction process. mainly involve the construction execution based on the planning and designs prepared by the consultant engineer, list of activities is as under;
- Preliminary Site Works
- Survey and layout
- Excavation work
- Compaction and Site Tests
- Foundation Construction works
- Plinth and Beam Works
- Grade Slab Works
- Columns works
- Beam and Slab Works
- Masonry Works
- Roof Slab / Parapet wall
- MEP works
- Finishing Works
- External Works
- Project Completion
Preliminary Site Works
Preliminary site works first post-contract activity to prepare the site for construction work. This activity involves cleaning the project site from debris, unwanted materials, tree roots, removing any obstacles such as loose soil, demolition of any building if it existed, mobilization of building materials, workers, and providing infrastructure to facilitate the staff and workers.
Survey and Layout
Once the building site is cleansed from debris, the building layout is established with surveying equipment. Modern survey equipment consists of theodolite, total station, and level machine. The precise building position is determined from the coordinates mentioned in the drawings. During the survey, gate levels are marked by the surveyor, and the excavation depth is determined.
The location of access roads, storage facilities of construction materials, labor dormitory, and officers for engineers and supervisory staff are installed. If the building construction is a major project, there also needs to be the establishment of the consultant’s office for effective supervision.
After the site layout setting up is completed. The excavation work begins with suitable excavation machines. Excavation work is one of the critical points of the building construction process, the surveying staff must be present at the site during the excavation process to determine the required depth and level based on the design drawings.
The most crucial part of the excavation process is taking safety precautions that are considered critical during the excavation and backfilling to prevent accidents on the site and save the life of laborers; this also helps avoid delays in the building construction process. If the construction site is located in an urban area and there are nearby service lines, we must take proper safety precautions to avoid contact with the service lines.
Compaction and site tests
Once the excavation depth is achieved, the bottom layer must be compacted to avoid any possible future settlement. If there is a requirement for any subgrade preparation, the coarse aggregate is the most suitable material to use as a base layer. there are various machines available to compact the grade level, such as smooth wheel roller, rubber tire roller, crawler, and tamping plate compactor. The subgrade must be compacted 90-95%.
Foundation Construction Works
Foundation is the load-bearing component of the building responsible to transfer the superstructure load to the underneath soil. Before proceeding to the foundation construction.
The Foundation layout must be marked according to the orientation and centerline provided in the foundation structural drawings. Anti-termite treatment is optional but the 100g-200g polythene sheet must be provided below the p.c.c. The p.c.c dimension must be greater than the foundation about 10 cm to provide support for formwork.
The foundation consists of reinforcement and concrete, while pouring the concrete, the concrete workability must be observed, and the concrete cube must be cast to later test in the lab and confirm the concrete strength as per the design.
The site engineer should attend and supervise all the activities to ensure the executed work is according to the specification, in some cases, prior to the concrete pouring works, authorities’ approval is required. The consultant supervisor engineer must attend all pouring activities to ensure the quality of work.
Plinth Beam Construction
The plinth beam is the element of substructure that is cast at (-10,15 cm) from the finish floor level. A plinth beam is provided to transfer and distribute the superstructure load on the substructure and further on the soil. There is a possibility that the plinth beam may be provided at different levels and directions.
A plinth beam may be erected directly from the excavation level or below the beam the solid block works is required. Prior to the backfilling, the bitumen coating must be provided on the footings and beams to secure the structure from dampness.
Once the structure is waterproof, the excavation should be filled in layers of 50 cm. Each layer must be compacted and treated properly to avoid settlement, if it is required, a compaction test may be carried out to observe the compaction strength.
Grade Slab Works
After the backfilling, there is a need to prepare the area for the grade slab. Site engineers must ensure that all MEP service outlets are installed, and 4mm to 6mm mesh steel is provided above the 200g polythene sheet. For grade slab recommended concrete is M15 or M20, or else as specified in the specification.
After the construction of the grade slab above the substructure. The R.C.C columns are erected to provide structural support to the beams and slab. The column construction works involve the construction of a 50mm-150mm column kicker. Placing steel reinforcement as per the design, setting up the formwork, providing support and leveling the column, and pouring the concrete.
This column must be checked by the consultant engineer prior to the closure of formwork to inspect the reinforcement and once the formwork is installed, the verticality of the column. The column reinforcement must be erected above the slab concrete level to provide sufficient overlapping for the steel for the construction of the above stories or provide support to the parapet wall.
During the concrete pouring, the concrete vibrator must be used to avoid a honeycomb in the concrete. The cubes must be prepared, to test at the lab to confirm the concrete strength as per specification, and the column must be cured for 14 days. The most common way to cure concrete is to cover the structure with a gunny bag tied around the column and sprayed with fresh water.
Slab and Beam Construction
After the construction of columns, the process of slab and beam construction starts, which is considered a major activity in the building construction process. The process starts with the placement of formworks for beams and slabs, the appropriate slab level must be observed with help of site surveyors.
The second step is installing reinforcements for beams and slabs respectively according to the structural drawings and specifications. At this step, the consultant engineer and the concerned inspection authority must inspect the reinforcement, formwork support, and any other necessary details.
The third step involves embedding other objects such as MEP fixtures, this requires high attention as the building’s future services depend on this function to function properly. This process should be completed with the final inspection of the MEP engineer.
The fourth step is pouring concrete for beams and slabs, concrete levels must be marked to reduce the risk of high load on the structure and pouring additional concrete to increase the cost. Once the concrete is completed the surface must be finished properly to avoid the risk of hairline cracks development, and finally, cure the concrete with various available techniques.
These steps must be followed in constructing columns, beams, and slabs for other stories above. It is the responsibility of site engineers to supervise all activities and ensure that the project is being executed according to the specification.
Masonry Wall Construction
The Masonry walls or architectural walls construction begins when the formwork and its supports are removed after the specified time of 10-14 days. Masonry walls are usually non-load bearing walls constructed to provide partition and privacy. And give a proper building look to the under-construction building.
There are a variety of materials being used for the construction of masonry walls, such as bricks, concrete blocks, cinder blocks, insulated blocks. Etc. It is important to provide holdfast at every 90 cm to provide a strong connection and steel mesh to cover the joint.
Lintels are also provided above the doors and windows to carry the load above them. G.I lintels speed up the building construction process as they are ready to fix and above them, the masonry work can be executed.
Roof Slab / Parapet wall
The roof slab is the top and last structural element of building construction. It is built according to the design to accommodate the service outlets such as HVAC, water storage, External AC units. Waterproofing is required to save the building from water leakage and weather effects. The parapet wall up to 90 cm is also constructed to provide safety and add architectural features to the building elevations.
MEP works are Mechanical, Electrical, and Plumbing works. It is supervised by MEP engineers in coordination with site engineers. The site engineer should take responsibility to prevent any damaging effect on structural elements like piercing beams, which is done by MEP works sometimes carelessly without any consultation of a structural engineer.
Mechanical and plumbing works in the building include installation of HVAC and ac, diffusers and ducts, thermal insulation works, prevent dampness, installation of fire fighting equipment including fire alarms, sparklers, and smoke detectors, installation of water supply and drainage, installation of kitchen and bathroom fixtures. These works are managed and supervised by Mechanical Engineers.
Electrical works included installation of power and lighting, emergency power, voice, and data communication systems, CCTV, lighting protection system, etc, this is supervised by an Electrical Engineer.
Finishing work such as internal plastering begins, after the electrical and mechanical conduits are installed, the external plastering can be done as soon as the masonry works are completed. Finishing works included the installation of tile, marble, or granite on the floor, painting works after the plastering, installation of wood components such as doors, installation of windows, installation of false ceiling, etc. This is done under the supervision of a civil site engineer.
External works include installation of interlock or floor, construction of manhole, installation of the main gate, construction of the septic tank, once all the utility services are installed, finally, the interlocks/ flooring is installed.
The building completion certificate is the final activity of the building construction process. it is issued by the responsible authorities once all the structural and architectural works including MEP and finishing works are completed. The authority responsible engineer will visit the construction site to observe the completion, if he is satisfied, he will issue a completion certificate, otherwise, a snag list will be prepared, which must be rectified in order to obtain the completion certificate.