First fix plumbing is the pipework that goes in before walls, floors and ceilings are finished, such as running supply and waste pipes to where fixtures will go. Second fix is the stage after plastering, tiling or flooring, when the taps, toilets, basins, showers and other fittings are connected.
Splitting the work into two stages lets other trades finish the room between them. The terms are common in building projects, so it helps to know what they mean.
What Happens at First Fix
At first fix, the plumber runs the hot and cold supply pipes and the waste pipes to the planned positions of each fixture. Pipes may be run under floors, in stud walls or through ceilings, and capped off ready for later.
This is also the stage to fit things that will be hidden, such as frames for wall-hung toilets or basins, concealed cisterns and shower valves set into walls. Getting positions right at this stage matters, because changing them later can mean opening up finished walls.
Pipework is often tested at this stage to check for leaks before it is covered. Finding a problem now is far easier than after the walls are tiled.
Between the Stages
Once first fix is done, other trades can carry on. This may include plastering, boarding, tiling, flooring and electrical work. Protecting capped pipes and marking their positions can help avoid damage, such as a nail or screw going through a hidden pipe.
Any changes to the layout are much easier to make before this stage than after it. Taking photos of the pipe runs before they are covered can also be useful for future repairs or alterations.
What Happens at Second Fix
At second fix, the plumber fits and connects the visible fixtures and fittings, such as taps, basins, toilets, shower heads, baths and appliance connections. Wastes and traps are connected, and everything is checked for leaks and proper drainage.
If a fixture turns out not to match the pipe positions, adjustments may be needed, which is why choosing fittings early helps.
Second fix depends on the fixtures being on site and the room being ready, so delays to other trades or deliveries can affect when it happens.
Why It Matters When Planning
Knowing the stages can help you plan your project and choose fixtures in good time. Some fittings need specific pipe positions or concealed parts, so it helps to have them chosen before first fix.
It also helps to agree what each stage includes, so it is clear who is responsible for what. Our page on professional plumbing installation explains how installation work is planned and carried out. For bathroom projects, our bathroom plumbing page may also help.
If you are planning new plumbing in Poole, a plumber can explain how first and second fix will work for your project.