What does in situ mean?
In situ (also referred to as insitu or in-situ) is a Latin phrase that is commonly used in the construction industry to mean ‘on site’, ‘in place’ or ‘in position’. It refers to work which is carried out on the construction site itself, often in the finished position, as opposed to in an off-site location as with prefabrication or pre-assembly techniques.
The most common use of the term 'in situ' is in relation to concrete, with components such as a slabs, beams and piles being described as ‘cast in situ’ to distinguish them from precast concrete components, that are manufactured off site.
Generally, in situ construction techniques tend to be more labour- and time-intensive, however, they are more flexible in response to changes that may arise on site. Prefabricated components, in contrast, must be designed in detail in advance, with limited scope for changes once they have been manufactured.
In situ can also be used to refer to in situ testing, for example, tests carried out on site to determine the density or shear strength of soils. For more information, see: Insitu testing of soils.
Also, in the context of soil, in situ can refer to soil which is still in its original condition and that has not been ‘cut’ from one area of a site and ‘filled’ in elsewhere.
See also: On site.
[edit] Related articles on Designing Buildings
Featured articles and news
The UK's Modern Industrial Strategy: A 10 year plan
Previous consultation criticism, current key elements and general support with some persisting reservations.
Building Safety Regulator reforms
New roles, new staff and a new fast track service pave the way for a single construction regulator.
Architectural Technologist CPDs and Communications
CIAT CPD… and how you can do it!
Cooling centres and cool spaces
Managing extreme heat in cities by directing the public to places for heat stress relief and water sources.
Winter gardens: A brief history and warm variations
Extending the season with glass in different forms and terms.
Restoring Great Yarmouth's Winter Gardens
Transforming one of the least sustainable constructions imaginable.
Construction Skills Mission Board launch sector drive
Newly formed government and industry collaboration set strategy for recruiting an additional 100,000 construction workers a year.
New Architects Code comes into effect in September 2025
ARB Architects Code of Conduct and Practice available with ongoing consultation regarding guidance.
Welsh Skills Body (Medr) launches ambitious plan
The new skills body brings together funding and regulation of tertiary education and research for the devolved nation.
Paul Gandy FCIOB announced as next CIOB President
Former Tilbury Douglas CEO takes helm.
UK Infrastructure: A 10 Year Strategy. In brief with reactions
With the National Infrastructure and Service Transformation Authority (NISTA).
Ebenezer Howard: inventor of the garden city. Book review.
The Grenfell Tower fire, eight years on
A time to pause and reflect as Dubai tower block fire reported just before anniversary.
Airtightness Topic Guide BSRIA TG 27/2025
Explaining the basics of airtightness, what it is, why it's important, when it's required and how it's carried out.
Construction contract awards hit lowest point of 2025
Plummeting for second consecutive month, intensifying concerns for housing and infrastructure goals.
Understanding Mental Health in the Built Environment 2025
Examining the state of mental health in construction, shedding light on levels of stress, anxiety and depression.