Construction

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,[citation needed] design, and financing and continues until the project is built and ready for use.

Large-scale construction requires collaboration across multiple disciplines. An architect normally manages the job, and a construction manager, design engineer, construction engineer or project manager supervises it. For the successful execution of a project, effective planning is essential. Those involved with the design and execution of the infrastructure in question must consider zoning requirements, the environmental impact of the job, the successful scheduling, budgeting, construction-site safety, availability and transportation of building materials, logistics, inconvenience to the public caused by construction delays and bidding, etc. The largest construction projects are referred to as mega projects.

Types of construction

In general, there are three sectors of construction: buildings, infrastructure and industrial. Building construction is usually further divided into residential and non-residential (commercial/institutional). Infrastructure is often called heavy/highway, heavy civil or heavy engineering. It includes large public works, dams, bridges, highways, water/wastewater and utility distribution. Industrial includes refineries, process chemical, power generation, mills and manufacturing plants. There are other ways to break the industry into sectors or markets.

Engineering News-Record (ENR) is a trade magazine for the construction industry. Each year, ENR compiles and reports on data about the size of design and construction companies. They publish a list of the largest companies in the United States (Top-40) and also a list the largest global firms (Top-250, by amount of work they are doing outside their home country). In 2014, ENR compiled the data in nine market segments. It was divided as transportation, petroleum, buildings, power, industrial, water, manufacturing, sewer/waste, telecom, hazardous waste plus a tenth category for other projects. In their reporting on the Top 400, 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 otherwise engage in construction. To recognize the differences of companies in this sector, it is divided into three subsectors: building construction, heavy and civil engineering construction, 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

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 typically include various common elements, such as design, financial, estimating and legal considerations, many projects of varying sizes 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 trades people. As residential construction (as well as all other types of construction) can generate a lot of waste, careful planning again is needed here.

Residential construction

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:

•             Develop floor plans and obtain a materials list for estimations (more recently performed with estimating software)

•             Obtain government building approval if necessary

•             Clear the building site

•             Survey to stake out for the foundation

•             Excavate the foundation and dig footers.

•             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 Framing

•             Frame interior walls with wooden 2x4s

•             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 (cement board 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 cement board for wet areas, such as the bathroom and kitchen backsplash

•             Install final floor covering, such as floor tile, carpet, or wood flooring

•             Install major appliances

•             Unless the original owners are building the house, at this point it is typically sold or rented.