First fix
Plain English. Practical detail. UK context.
First fix is the stage when concealed or structural components are installed before finishes cover them. Its exact scope varies by trade and contract.
Last reviewed: (editorial review against the public sources listed below).
What it means in practice
Define the term in the programme rather than assuming every trade uses it identically. For carpentry it may include framing and structural timber; for building services it commonly includes routes and hidden pipework or cables. Agree what must be inspected, tested or photographed before boarding and plastering.
Coordinate positions against the finished design. A cable or pipe installed neatly in the wrong place can still cause expensive disruption when units, tiles or doors are fitted.
For homeowners
Expect the building to look unfinished during first fix. This is the useful time to confirm socket locations, switches, heating controls and bathroom layouts against the agreed plans. Ask before requesting changes: even before plastering, moving one service can affect others or alter the programme.
Practical checks
Use a room-by-room sign-off list before concealment. Record any unresolved design choices, and do not let the next trade cover work which still requires checking.
A useful stop point before concealment
Make the first-fix review specific to the room and trade. In a kitchen, relate cabinet drawings to water, waste, power and appliance spaces; in a bathroom, check the waterproofing background, valve positions and access; in carpentry, confirm door openings and support for later fittings. Photographs help later maintenance but do not replace required tests or inspections. Record routes with a meaningful reference rather than a close-up from which the room cannot be identified. Trainees should learn to ask what must remain accessible and what evidence is needed before another trade closes the surface. Discovering a misplaced outlet during second fix is usually too late for a simple agreement about who should have checked it.
Inspection responsibilities and payment stages
First fix is not a statutory certification or a universally defined invoice milestone. The contract should state what completion of that stage means and what evidence is required for payment. Applicable building standards still govern the actual work: England's Approved Documents cover structure, fire, sound and services, while other UK nations use their own guidance. The relevant specialist should verify concealed work within their responsibility. If an inspection fails or a design choice is unresolved, agree the remedy and programme before boarding. A signed room checklist records a decision; it cannot waive safety duties or certify work which was not inspected.
Frequently asked questions
Does first fix mean the job is halfway complete?
No. It describes a stage and type of work, not a guaranteed percentage of cost or time. The balance varies substantially between projects and trades.
Does first-fix sign-off replace electrical or plumbing tests?
No. A coordination check does not replace technical verification, required inspections or the appropriate completion certificates for the work.
Sources and further reading
Public sources and further reading. Sources checked: 8 November 2026. Consult the original for details and later changes.