Construction is the process of constructing a building or infrastructure.
Construction differs from manufacturing in that manufacturing typically involves mass production of similar items without a designated purchaser, while construction typically takes place on location for a known client.
Construction as an industry comprises six to nine percent of the gross domestic product of developed countries.
Construction starts with planning, design, and financing; it continues until the project is built and ready for use.Large-scale construction requires collaboration across multiple disciplines. A project manager normally manages the job, and a construction manager, design engineer, construction engineer or architect supervises it. Those involved with the design and execution must consider zoning requirements, environmental impact of the job, scheduling, budgeting, construction-site safety, availability and transportation of building materials, logistics, inconvenience to the public caused by construction delays and bidding. Large construction projects are sometimes referred to as megaprojects.
Construction is a general term meaning the art and science to form objects, systems, or organizations,and comes from Latin constructionem (from com- “together” and struere “to pile up”) and Old French construction.Construction is used as a verb: the act of building, and a noun: how a building was built, the nature of its structure.
Military residential unit construction by U.S. Navy personnel in Afghanistan
Engineering News-Record (ENR), a trade magazine for the construction industry, each year compiles and reports data about the size of design and construction companies. In 2014, ENR compiled the data in nine market segments divided as transportation, petroleum, buildings, power, industrial, water, manufacturing, sewer/waste, telecom, hazardous waste and a tenth category for other projects. In their reporting, they used data on transportation, sewer, hazardous waste and water to rank firms as heavy contractors.
The Standard Industrial Classification and the newer North American Industry Classification System have a classification system for companies that perform or engage in construction. To recognize the differences of companies in this sector, it is divided into three subsectors: building construction, heavy and civil engineeringconstruction, and specialty trade contractors. There are also categories for construction service firms (e.g., engineering, architecture) and construction managers (firms engaged in managing construction projects without assuming direct financial responsibility for completion of the construction project).
Building construction is the process of adding structure to real property or construction of buildings. The majority of building construction jobs are small renovations, such as addition of a room, or renovation of a bathroom. Often, the owner of the property acts as laborer, paymaster, and design team for the entire project. Although building construction projects consist of common elements such as design, financial, estimating and legal considerations, projects of varying sizes may reach undesirable end results, such as structural collapse, cost overruns, and/or litigation. For this reason, those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome.
Commercial building construction is procured privately or publicly utilizing various delivery methodologies, including cost estimating, hard bid, negotiated price, traditional, management contracting, construction management-at-risk, design & build and design-build bridging.
Residential construction practices, technologies, and resources must conform to local building authority regulations and codes of practice. Materials readily available in the area generally dictate the construction materials used (e.g. brick versus stone, versus timber). Cost of construction on a per square meter (or per square foot) basis for houses can vary dramatically based on site conditions, local regulations, economies of scale (custom designed homes are often more expensive to build) and the availability of skilled tradesmen. Residential construction as well as other types of construction can generate waste such that planning is required.
According to McKinsey research, productivity growth per worker in construction has lagged behind many other industries across different countries including in the United States and in European countries. In the United States, construction productivity per worker has declined by half since the 1960s.
The most popular method of residential construction in North America is wood-framed construction. Typical construction steps for a single-family or small multi-family house are:
- Obtain an engineered soil test of lot where construction is planned. From an engineer or company specializing in soil testing.
- Develop floor plans and obtain a materials list for estimations (more recently performed with estimating software)
- Obtain structural engineered plans for foundation and structure. To be completed by either a licensed engineer or architect. To include both a foundation and framing plan.
- Obtain lot survey
- Obtain government building approval if necessary
- If required obtain approval from HOA (homeowners association) or ARC (architectural review committee)
- Clear the building site (demolition of existing home if necessary)
- Survey to stake out for the foundation
- Excavate the foundation and dig footers (Scope of work is dependent of foundation designed by engineer)
- Install plumbing grounds
- Pour a foundation and footers with concrete
- Build the main load-bearing structure out of thick pieces of wood and possibly metal I-beams for large spans with few supports. See framing (construction)
- Add floor and ceiling joists and install subfloor panels
- Cover outer walls and roof in OSB or plywood and a water-resistive barrier.
- Install roof shingles or other covering for flat roof
- Cover the walls with siding, typically vinyl, wood, or brick veneer but possibly stone or other materials
- Install windows
- Frame interior walls with wooden 2×4s
- Add internal plumbing, HVAC, electrical, and natural gas utilities
- Building inspector visits if necessary to approve utilities and framing
- Install insulation and interior drywall panels (cementboard for wet areas) and to complete walls and ceilings
- Install bathroom fixtures
- Spackle, prime, and paint interior walls and ceilings
- Additional tiling on top of cementboard for wet areas, such as the bathroom and kitchen backsplash
- Installation of final floor covering, such as floor tile, carpet, or wood flooring
- Installation of major appliances
- Unless the original owners are building the house, at this point it is typically sold or rented.
In the industrialized world, construction usually involves the translation of designs into reality. A formal design team may be assembled to plan the physical proceedings, and to integrate those proceedings with the other parts. The design usually consists of drawings and specifications, usually prepared by a design team including architect, civil engineers, mechanical engineers, electrical engineers, structural engineers, fire protection engineers, planning consultants, architectural consultants, and archaeological consultants. The design team is most commonly employed by (i.e. in contract with) the property owner. Under this system, once the design is completed by the design team, a number of construction companies or construction management companies may then be asked to make a bid for the work, either based directly on the design, or on the basis of drawings and a bill of quantities provided by a quantity surveyor. Following evaluation of bids, the owner typically awards a contract to the most cost efficient bidder.
The best modern trend in design is toward integration of previously separated specialties, especially among large firms. In the past, architects, interior designers, engineers, developers, construction managers, and general contractors were more likely to be entirely separate companies, even in the larger firms. Presently, a firm that is nominally an “architecture” or “construction management” firm may have experts from all related fields as employees, or to have an associated company that provides each necessary skill. Thus, each such firm may offer itself as “one-stop shopping” for a construction project, from beginning to end. This is designated as a “design build” contract where the contractor is given a performance specification and must undertake the project from design to construction, while adhering to the performance specifications.
Several project structures can assist the owner in this integration, including design-build, partnering and construction management. In general, each of these project structures allows the owner to integrate the services of architects, interior designers, engineers and constructors throughout design and construction. In response, many companies are growing beyond traditional offerings of design or construction services alone and are placing more emphasis on establishing relationships with other necessary participants through the design-build process.
The increasing complexity of construction projects creates the need for design professionals trained in all phases of the project’s life-cycle and develop an appreciation of the building as an advanced technological system requiring close integration of many sub-systems and their individual components, including sustainability. Building engineering is an emerging discipline that attempts to meet this new challenge.
Construction projects can suffer from preventable financial problems. Underbids happen when builders ask for too little money to complete the project. Cash flow problems exist when the present amount of funding cannot cover the current costs for labour and materials, and because they are a matter of having sufficient funds at a specific time, can arise even when the overall total is enough. Fraud is a problem in many fields, but is notoriously prevalent in the construction field. Financial planning for the project is intended to ensure that a solid plan with adequate safeguards and contingency plans are in place before the project is started and is required to ensure that the plan is properly executed over the life of the project.
Mortgage bankers, accountants, and cost engineers are likely participants in creating an overall plan for the financial management of the building construction project. The presence of the mortgage banker is highly likely, even in relatively small projects since the owner’s equity in the property is the most obvious source of funding for a building project. Accountants act to study the expected monetary flow over the life of the project and to monitor the payouts throughout the process. Cost engineers and estimators apply expertise to relate the work and materials involved to a proper valuation. Cost overruns with government projects have occurred when the contractor identified change orders or project changes that increased costs, which are not subject to competition from other firms as they have already been eliminated from consideration after the initial bid.
Large projects can involve highly complex financial plans and often start with a conceptual estimate performed by a building estimator. As portions of a project are completed, they may be sold, supplanting one lender or owner for another, while the logistical requirements of having the right trades and materials available for each stage of the building construction project carries forward. In many English-speaking countries, but not the United States, projects typically use quantity surveyors.
This approach has become more common in recent years, and also involves the client contracting a single entity that both provides a design and builds it. In some cases, the design-build package can also include finding the site, arranging funding and applying for all necessary statutory consents.
The owner produces a list of requirements for a project, giving an overall view of the project’s goals. Several D&B contractors present different ideas about how to accomplish these goals. The owner selects the ideas they like best and hires the appropriate contractor. Often, it is not just one contractor, but a consortium of several contractors working together. Once these have been hired, they begin building the first phase of the project. As they build phase 1, they design phase 2. This is in contrast to a design-bid-build contract, where the project is completely designed by the owner, then bid on, then completed.
Kent Hansen pointed out that state departments of transportation usually use design build contracts as a way of progressing projects when states lack the skills-resources. In such departments, design build contracts are usually employed for very large projects.
Sustainability in construction
Sustainability during the construction phase is one of the aspects of “green building,” defined by the United States Environmental Protection Agency (EPA) as “the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building’s life-cycle from siting to design, construction, operation, maintenance, renovation and deconstruction.
Technical and specialized occupations require more training as a greater technical knowledge is required. These professions also hold more legal responsibility. A short list of the main careers with an outline of the educational requirements are given below:
- Architect – Typically holds 1, undergraduate 3-year degree in architecture + 1, post-graduate 2-year degree (DipArch or BArch) in architecture plus 24 months’ experience within the industry. To use the title “architect” the individual must be registered on the Architects Registration Board register of Architects.
- Civil engineer – Typically holds a degree in a related subject. The Chartered Engineer qualification is controlled by the Engineering Council, and is often achieved through membership of the Institution of Civil Engineers. A new university graduate must hold a master’s degree to become chartered; persons with bachelor’s degrees may become an Incorporated Engineer.
- Building services engineer – Often referred to as an “M&E Engineer” typically holds a degree in mechanical or electrical engineering. Chartered Engineer status is governed by the Engineering Council, mainly through the Chartered Institution of Building Services Engineers.
- Project manager – Typically holds a 4-year or greater higher education qualification, but are often also qualified in another field such as architecture, civil engineering or quantity surveying.
- Structural engineer – Typically holds a bachelor’s or master’s degree in structural engineering. A P.ENG is required from the Professional Engineers Ontario (Canada). New university graduates must hold a master’s degree to gain chartered status from the Engineering Council, mainly through the Institution of Structural Engineers (UK).
- Quantity surveyor – Typically holds a bachelor’s degree in quantity surveying. Chartered status is gained from the Royal Institution of Chartered Surveyors.
- Civil estimators are professionals who typically have a background in civil engineering, construction project management, or construction supervision.