First fix (sometimes described as shell and first fix ) is a short-hand term used to describe the processes that are undertaken during construction works up to the point of applying internal surfaces – typically plaster. It is normally used in relation to the work of specific trades such as carpenters, plumbers and electricians.
Generally first fix will include constructing the structure, cladding, flooring, doorframes, stairs and so on and installing cables for electrical and ICT distribution, pipework for water and gas distribution and heating ventilating and air-conditioning (HVAC) distribution. First fix is not normally visible when looking at the finished building. Where possible first fix should be tested before second fix (for example plumbing riser stacks).
Second fix takes place after the internal surfaces have been applied. It comprises those items that are visible in a finished area and are held back to avoid damage, or sadly sometimes theft. This may include fitting internal doors, skirting, architraves, handrails, fixtures and fittings, including connection of appliances (such as electrical equipment, sanitaryware, radiators and so on) testing and commissioning.
Typically there will be a change of trades operating on the site, and a break in activity for some trades between first and second fix.
In hotels and residential work there is sometimes a third fix of fixtures and fittings of high value that require fitting or service connections such as chandeliers, white goods, picture-lit artwork and fabrics.
As first fix, second fix and third fix do not have accurate standard definitions, it is very important that contract documentation sets out precisely what work is to be carried out and by who, rather than relying on ambiguous short-hand terms.
 Related articles on Designing Buildings Wiki
Featured articles and news
It was the tallest structure in the world for 3,800 years, but to this day the exact construction techniques are a mystery.
Shortlist for the industry's most coveted award announced.
Government responds to Mark Farmer's review of industry, rejecting the call for a levy on clients.
Peter Hansford to examine what wider lessons can be learned from the fire.
Every project is subject to uncertainty. How can construction better understand uncertainty for performance improvement?
MAD Architects reveal their designs for a futuristic campus for electric car manufacturer.
Homebuyers could borrow more with better forecasting of energy bills, according to industry consortium's new report.
Read our introductory article on carbon capture and storage.
Have a look at Frank Gehry's Binoculars Building in Los Angeles.
BRE publish new Loss Prevention Standard seeking to minimise fire risk from ducting.
How do we tell which infrastructure projects will work?
CIAT announce the establishment of a Working Group in light of Grenfell and call for contributions.
In 1900, 15% of global population lived in cities. Now it’s over 50%. Which is why we need ‘hydroinformatics’ to consume smarter.
Have a look at these competition-winning designs for a new residential development in Eindhoven.