thumb|A large construction site of the _area_in_[[Helsinki">Kalasatama
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Construction is a general term meaning the [[art]] and [[science]] to form [[Physical object|objects]], [[systems]], or [[organizations]],
["Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dictionary'' Second Edition on CD-ROM (v. 4.0) Oxford University Press 2009]
and comes from Latin
''constructio'' (from ''com-'' "together" and ''struere'' "to pile up") and Old French
''construction''. To construct is the verb
: the act of building, and the noun
is construction: how something is built, the nature of its structure.
In its most widely used context, construction covers the processes involved in delivering building
and industrial facilities, and associated activities through to the end of their life. It typically starts with planning
, and design
, and continues until the asset is built and ready for use; construction also covers repairs and maintenance work, any works to expand, extend and improve the asset, and its eventual demolition
, dismantling or decommission
As an industry
, construction accounts for more than 10% of global GDP
(6-9% in developed countries
) and employs around 7% of the global workforce - over 273m people. The output of the global construction industry was worth an estimated $10.8 trillion in 2017.
The first huts
and shelters were constructed by hand or with simple tools. As cities
grew during the Bronze Age
, a class of professional craftsmen
, like bricklayer
s and carpenters
, appeared. Occasionally, slaves
were used for construction work. In the Middle Ages
, the artisan craftsmen were organized into guild
s. In the 19th century, steam-powered machinery appeared, and, later, diesel- and electric-powered vehicles such as cranes
s and bulldozer
has been increasingly popular in the 21st century. Some estimates suggest that 40% of construction projects are now fast-track construction.
Construction industry sectors
Broadly, there are three sectors of construction: buildings, infrastructure and industrial:
* Building construction is usually further divided into residential and non-residential.
* Infrastructure, also called heavy civil or heavy engineering
, includes large public works, dams, bridges, highways, railways, water or wastewater and utility distribution.
* Industrial construction includes offshore construction
(mainly of energy installations), mining and quarrying, refineries
, chemical processing, power generation
, mills and manufacturing plants
The industry can also be classified into sectors or markets. For example, ''Engineering News-Record
'' (''ENR''), a US-based construction trade magazine, has compiled and reported data about the size of design and construction contractors. In 2014, it split the data into nine market segments: transportation, petroleum
, buildings, power, industrial, water, manufacturing, sewer/waste, telecom
, hazardous waste, and a tenth category for other projects. ''ENR'' 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
classify companies that perform or engage in construction into three subsectors: building construction, heavy and civil engineering construction, and specialty trade contractors. There are also categories for professional services firms (e.g., engineering
, project management
Building construction is the process of adding structures to areas of land, also known as real property
sites. Typically, a project is instigated by or with the owner of the property (who may be an individual or an organisation); occasionally, land may be compulsorily purchased
from the owner for public use.
Residential construction may be undertaken by individual land-owners (self-build
), by specialist house-builders
, by property developer
s, by general contractor
s, or by providers of public or social housing
(eg: local authorities, housing association
s). Where local zoning
policies allow, mixed-use development
s may comprise both residential and non-residential construction (eg: retail, leisure, offices, public buildings, etc).
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 (eg: brick
versus stone versus timber
). Costs of construction on a per square meter (or per square foot) basis for house
s can vary dramatically based on site conditions, access routes, local regulations, economies of scale
(custom-designed homes are often more expensive to build) and the availability of skilled tradespeople.
Depending upon the type of building
, non-residential building construction can be procured by a wide range of private and public organisations, including local authorities, educational and religious bodies, transport undertakings, retailers, hoteliers, property developers, financial institutions and other private companies. Most construction in these sectors is undertaken by general contractors.
Civil engineering covers the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, tunnels, airports, water and sewerage systems, pipelines, and railways. Some general contractors have expertise in civil engineering; civil engineering contractors are firms dedicated to work in this sector, and may specialise in particular types of infrastructure.
includes offshore construction (mainly of energy installations: oil and gas platforms
, wind power
and other processing plants, power station
s, steel mill
s and factories
Some construction projects are small renovations or repair jobs, where the owner may act as designer, paymaster and laborer for the entire project. However, more complex or ambitious projects usually require additional multi-disciplinary expertise and manpower, so the owner may commission one or more specialist businesses to undertake detailed planning, design, construction and handover of the work. Often the owner will appoint one business to oversee the project (this may be a designer
, a contractor
, a construction manager
, or other advisor); such specialists are normally appointed for their expertise in project delivery, and will help the owner define the project brief
, agree a budget
, liaise with relevant public authorities, and procure the services of other specialists (the supply chain
, comprising subcontractor
are agreed for the delivery of services by all businesses, alongside other detailed plans aimed at ensuring legal, timely, on-budget and safe delivery of the specified works.
Design, finance, and legal aspects overlap and interrelate. The design must be not only structurally sound and appropriate for the use and location, but must also be financially possible to build, and legal to use. The financial structure must be adequate to build the design provided, and must pay amounts that are legally owed. Legal structures integrate design with other activities, and enforce financial and other construction processes.
These processes also affect procurement strategies. Clients may, for example, appoint a business to design the project after which a competitive process is undertaken to appoint a lead contractor to construct the asset (design–bid–build
); they may appoint a business to lead both design and construction (design-build
); or they may directly appoint a designer, contractor and specialist subcontractors (construction management
). Some forms of procurement emphasise collaborative relationships (partnering
, alliancing) between the client, the contractor, and other stakeholders within a construction project, seeking to ameliorate often highly competitive and adversarial industry practices.
When applicable, a proposed construction project must comply with local land-use planning
policies including zoning
and building code
requirements. A project will normally be assessed (by the 'authority having jurisdiction', AHJ, typically the municipality
where the project will be located) for its potential impacts on neighbouring properties, and upon existing infrastructure (transportation, social infrastructure, and utilities including water supply, sewerage, electricity, telecommunications, etc). Data may be gathered through site analysis
, site survey
s and geotechnical investigation
s. Construction normally cannot start until planning permission
has been granted, and may require preparatory work to ensure relevant infrastructure has been upgraded before building work can commence. Preparatory works will also include surveys of existing utility lines to avoid damage causing outages and other hazardous situations.
Some legal requirements come from ''malum in se
'' considerations, or the desire to prevent indisputably bad phenomena, e.g. explosions or bridge collapses. Other legal requirements come from ''malum prohibitum
'' considerations, or factors that are a matter of custom or expectation, such as isolating businesses from a business district or residences from a residential district. An attorney may seek changes or exemptions in the law that governs the land where the building will be built, either by arguing that a rule is inapplicable (the bridge design will not cause a collapse), or that the custom is no longer needed (acceptance of live-work spaces has grown in the community).
During construction of a building, a municipal building inspector usually inspects the ongoing work periodically to ensure that construction adheres to the approved plans and the local building code. Once construction is complete, any later changes made to a building or other asset that affect safety, including its use, expansion, structural integrity, and fire protection
, usually require municipality approval.
Depending on the type of project, mortgage bank
s, and cost engineers
may participe in creating an overall plan for the financial management of a 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. Professionals including cost engineers, estimators
and quantity surveyor
s apply expertise to relate the work and materials involved to a proper valuation.
Financial planning ensures adequate safeguards and contingency plans are in place before the project is started, and ensures that the plan is properly executed over the life of the project. 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; such problems may arise even when the overall budget is adequate, presenting a temporary issue. 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. Fraud
is also an occasional construction issue.
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. Public–private partnership
s (PPPs) or private finance initiative
s (PFIs) may also be used to help delivery major projects. According to McKinsey
in 2019, the "vast majority of large construction projects go over budget and take 20% longer than expected".
A construction project is a complex net of construction contract
s and other legal obligations, each of which all parties must carefully consider. A contract is the exchange of a set of obligations between two or more parties, and provides structures to manage issues. For example, construction delays can be costly, so construction contracts set out clear expectations and clear paths to manage delays. Poorly drafted contracts can lead to confusion and costly disputes.
At the start of a project, legal advisors seek to identify ambiguities and other potential sources of trouble in the contract structures, and to present options for preventing problems. During projects, they work to avoid and resolve conflicts that arise. In each case, the lawyer facilitates an exchange of obligations that matches the reality of the project.
Traditional or Design-bid-build
Design-bid-build is the most common and well-established method of construction procurement. In this arrangement, the architect
or builder acts for the client as the project coordinator. They design the works, prepare specifications and design deliverables (models, drawings, etc), administer the contract, tender
the works, and manage the works from inception to completion. In parallel, there are direct contractual links between the client and the main contractor, who, in turn, has direct contractual relationships with subcontractors. The arrangement continues until the project is ready for handover.
Design-build became more common from the late 20th century, and involves the client contracting a single entity to provide design and construction. In some cases, the design-build package can also include finding the site, arranging funding and applying for all necessary statutory consents. Typically, the client invites several D&B contractors to submit proposals to meet the project brief and then selects a preferred supplier. Often this will be a consortium
involving a design firm and a contractor (sometimes more than one of each). In the United States, departments of transportation
usually use design-build contracts as a way of progressing projects where states lack the skills or resources, particularly for very large projects.
In a construction management arrangement, the client enters into separate contracts with the designer (architect or engineer), a construction manager
, and individual trade contractors
. The client takes on the contractual role, while the construction or project manager provides the active role of managing the separate trade contracts, and ensuring that they complete all work smoothly and effectively together. This approach is often used to speed up procurement processes, to allow the client greater flexibility in design variation throughout the contract, to enable the appointment of individual work contractors, to separate contractual responsibility on each individual throughout the contract, and to provide greater client control.
In the industrialized world, construction usually involves the translation of designs into reality. Most commonly (ie: in a design-bid-build project), the design team is employed by (i.e. in contract with) the property owner. Depending upon the type of project, a design team may include architect
s, civil engineer
s, mechanical engineers
, electrical engineers
, structural engineer
s, fire protection engineers
, planning consultant
s, architectural consultants, and archaeological consultants. A 'lead designer' will normally be identified to help coordinate different disciplinary inputs to the overall design. This may be aided by integration of previously separate disciplines (often undertaken by separate firms) into multi-disciplinary firms with experts from all related fields, or by firms establishing relationships to support design-build processes.
The increasing complexity of construction projects creates the need for design professionals trained in all phases of a project's life-cycle and develop an appreciation of the asset as an advanced technological system requiring close integration of many sub-systems and their individual components, including sustainability. For buildings, building engineering
is an emerging discipline that attempts to meet this new challenge.
Traditionally, design has involved the production of sketch
and engineering drawing
s, and specifications
. Until the late 20th century, drawings were largely hand-drafted
; adoption of computer-aided design
(CAD) technologies then improved design productivity, while the 21st century introduction of building information modeling
(BIM) processes has involved use of computer-generated models that can be used in their own right or to generate drawings and other visualisations as well as capturing non-geometric data about building components and systems.
On some projects, work on site will not start until design work is largely complete; on others, some design work may be undertaken concurrently with the early stages of on-site activity (for example, work on a building's foundations may commence while designers are still working on the detailed designs of the building's internal spaces). Some projects may include elements that are designed for off-site construction
(see also prefabrication
and modular building
) and are then delivered to site ready for erection, installation or assembly.
Once contractors and other relevant professionals have been appointed and designs are sufficiently advanced, work may commence on the project site. Typically, a construction site will include a secure perimeter to restrict unauthorised access, site access control points, office and welfare accommodation for personnel from the main contractor and other firms involved in the project team, and storage areas for materials, machinery and equipment. According to the ''McGraw-Hill Dictionary of Architecture and Construction's'' definition, construction may be said to have ''started'' when the first feature of the permanent structure has been put in place, such as pile driving, or the pouring of slabs or footings.
Commissioning and handover
Commissioning is the process of verifying that all subsystems of a new building (or other asset) work as intended to achieve the owner's project requirements and as designed by the project's architects and engineers.
Maintenance, repair and improvement
Maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machine
ry, building infrastructure, and supporting utilities in industrial, business, governmental, and residential installations.
Demolition is the discipline of safely and efficiently tearing down building
s and other artificial structure
s. Demolition contrasts with deconstruction
, which involves taking a building apart while carefully preserving valuable elements for reuse purposes (recycling
- see also circular economy
Industry scale and characteristics
The output of the global construction industry was worth an estimated $10.8 trillion in 2017, and in 2018 was forecast to rise to $12.9 trillion by 2022.
As a sector, construction accounts for more than 10% of global GDP (in developed countries
, construction comprises 6-9% of GDP), and employs around 7% of the total employed workforce around the globe
(accounting for over 273 million full- and part-time jobs in 2014).
China has been the world's largest single construction market.
The United States is the second largest construction market with a 2018 output of $1.581 trillion.
In the United States in February 2020, around $1.4 trillion worth of construction work was in progress, according to the Census Bureau
, of which just over $1.0 trillion was for the private sector
(split roughly 55:45% between residential and nonresidential); the remainder was public sector
, predominantly for state and local government.
Construction is a major source of employment in most countries; high reliance on small businesses, and under-representation of women are common traits. For example:
* In the US, construction employed around 11.4m people in 2020, with a further 1.8m employed in architectural, engineering, and related professional services - equivalent to just over 8% of the total US workforce.
The construction workers were employed in over 843,000 organisations, of which 838,000 were privately held businesses.
In March 2016, 60.4% of construction workers were employed by businesses with fewer than 50 staff.
Women are substantially underrepresented (relative to their share of total employment), comprising 10.3% of the US construction workforce, and 25.9% of professional services workers, in 2019.
* In the United Kingdom, construction contributed £117 billion (6%) to UK GDP in 2018, and in 2019 employed 2.4m workers (6.6% of all jobs). These worked either for 343,000 'registered' construction businesses, or for 'unregistered' businesses, typically self-employed contractors;
just over one million small/medium-sized businesses, mainly self-employed individuals, worked in the sector in 2019, comprising about 18% of all UK businesses.
Women comprised 12.5% of the UK construction workforce.
According to McKinsey
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.
Construction GVA by country
Large-scale construction requires collaboration
across multiple disciplines. A project manager
normally manages the budget on the job, and a construction manager
, design engineer
, construction engineer
supervises it. Those involved with the design and execution must consider zoning requirements and legal issues, environmental impact
of the project, scheduling
ing and bidding
, construction site safety
, availability and transportation of building material
s, logistics, and inconvenience to the public, including those caused by construction delay
There are many routes to the different career
s within the construction industry. There are three main tiers based on educational background and training, which vary by country:
Unskilled and semi-skilled workers
Unskilled and semi-skilled workers provide general site labor, often have few or no construction qualifications, and may receive basic site training.
have typically served apprenticeship
s (sometimes in labor union
s) or received technical training; this group also includes on-site managers who possess extensive knowledge and experience in their craft
. Skilled manual occupations include carpenter
s, heavy equipment operator
s and masons
, as well as those involved in project management. In the UK
these require further education
qualifications, often in vocation
al subject areas, undertaken either directly after completing compulsory education
or through "on the job" apprenticeships.
Professional, technical or managerial personnel
Professional, technical and managerial personnel often have higher education
qualifications, usually graduate degrees
, and are trained to design and manage construction processes. These roles require more training as they demand greater technical knowledge, and involve more legal responsibility. Example roles (and qualification routes) include:
– Will usually have studied architecture
to degree level, and then undertaken further study and gained professional experience. In many countries, the title of "architect" is protected by law, strictly limiting its use to qualified people.
* Civil engineer
– Typically holds a degree in a related subject and may only be eligible for membership of a professional institution (such as the UK's ICE
) following completion of additional training and experience. In some jurisdictions, a new university graduate must hold a master's degree
to become chartered, and persons with bachelor's degree
s may become Incorporated Engineer
* Building services engineer
– May also be referred to as an "M&E" or "MEP engineer" and typically holds a degree in mechanical or electrical engineering.
* 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.
* Quantity surveyor
– Typically holds a bachelor's degree in quantity surveying. UK chartered status is gained from the Royal Institution of Chartered Surveyors
Construction is one of the most dangerous occupations in the world, incurring more occupational fatalities than any other sector in both the United States and in the European Union
In the US in 2019, 1,061, or about 20%, of worker fatalities in private industry occurred in construction.
In 2017, more than a third of US construction fatalities (366 out of 971 total fatalities) were the result of falls.
Proper safety equipment such as harnesses, hard hats and guardrails and procedures such as securing ladders and inspecting scaffolding
can curtail the risk of occupational injuries in the construction industry.
Other major causes of fatalities in the construction industry include electrocution, transportation accidents, and trench cave-ins.
Other safety risks for workers in construction include hearing loss
due to high noise exposure, musculoskeletal injury
, chemical exposure, and high levels of stress.
Besides that, the high turnover of workers in construction industry imposes a huge challenge of accomplishing the restructuring of work practices in individual workplaces or with individual workers. Construction has been identified by the National Institute for Occupational Safety and Health
(NIOSH) as a priority industry sector in the National Occupational Research Agenda
(NORA) to identify and provide intervention strategies regarding occupational health and safety issues.
Sustainability during the construction phase is an aspect 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."
* Agile construction
* Index of construction articles
* Outline of construction
* Real estate development
* Structural robustness
References and notes