Bathroom refit plumbing: first fix and second fix explained
Updated 1 October 2026 · 2 minute read
If you are planning a new bathroom, you will hear plumbers talk about first fix and second fix. It is worth knowing what they mean, because most bathroom problems start in the gap between the two.
First fix: everything you will never see
First fix happens with the old suite out and the walls and floor open. It covers:
- Moving or adding hot and cold supplies to where the new basin, toilet, bath or shower will sit
- Running wastes at the right falls so they drain properly
- Fitting the valve for a built in shower, at the right height and depth for the finished wall
- Pressure testing it all before anything is covered up
Get first fix wrong and it is buried behind tiles. That is why it matters most.
Second fix: everything you will
Second fix comes after the walls are boarded and tiled:
- Fitting the basin and vanity unit, the toilet and cistern, and the bath or tray
- Connecting taps, wastes and the shower controls
- Fitting the towel rail
- Testing every joint and sealing it all in
Why the same people should do both
When one company does first fix and another does second fix, a pipe that ends up two centimetres out becomes an argument. When the same team does both, it simply gets done right. On our bathroom work, the first fix and second fix are done by the same people.
Planning your bathroom
- Decide the layout first. Moving a toilet means moving a large waste, which is the biggest single factor in how much plumbing work is involved.
- Choose the shower type early. A mixer shower, an electric shower and a shower off an unvented cylinder all need different first fix.
- Think about hot water. A new bathroom can mean more demand. If your cylinder struggles now, a bigger shower will not help. See unvented cylinders.
- Add isolating valves everywhere. They make every future repair quicker.
Getting a bathroom priced
We do bathroom work across Bridgend county, from towel rails and vanity units to full refits, including in Pyle and Kenfig Hill. For a full refit we will want to see the room, then you get the price before we start. Tell us about your bathroom.
Keep reading
- How a plumber in Bridgend prices your job Why you will not find a plumbing price list here, what we need from you to price a job, and why the price is agreed before we start.
- Dripping tap? Washer, cartridge or a whole new tap How to tell what kind of tap you have, why it drips, and when a repair is worth it versus a new tap. A plain guide from a Bridgend plumber.
- Toilet keeps running? What is going on in the cistern The three usual reasons a toilet keeps filling or trickling into the pan, what you can check safely, and when to call a plumber in Bridgend.