Do I need to move out for a rewire?

Yes. It is dangerous and incredibly dusty. We have to chase channels into every wall and lift every floorboard. Living in the property during a full rewire is not feasible.

It is a brand name for an 'Unvented Hot Water Cylinder'. It stores hot water at mains pressure, allowing you to have powerful showers in multiple bathrooms simultaneously without a noisy pump.

How do I know if I have lead pipes?

Look at the pipe entering your home under the kitchen sink/stopcock. If it is dark grey and soft (you can scratch it with a coin), it is lead. It should be replaced immediately for health reasons.

The Nervous System: Rewiring & Plumbing Period Homes

By My Local London Builder Team | January 26, 2025

Neat copper pipework and electrical cabling in floor void

Summary: It is easy to spend your budget on things you can see—kitchen cabinets, tiles, and sofas. But if the "nervous system" behind the walls is failing, your beautiful renovation is a ticking time bomb. Most Victorian homes in London are running on electrical and plumbing infrastructure that is 40+ years old. This guide explains why ripping it out and starting again (The "First Fix") is the most painful but valuable investment you can make.

First Fix vs Second Fix

In construction, we divide M&E (Mechanical & Electrical) work into two distinct phases. Understanding this helps you plan your project timeline.

First Fix (The Construction Phase)

This happens when the house is a shell. No plaster, no floorboards. We chase channels into the brick walls, drill holes through joists, and run all the cables and pipes to the right locations. It is messy, noisy, and destructive.

Second Fix (The Finishing Phase)

This happens after the plastering and painting. We return to screw on the socket fronts, hang the radiators, install the toilet, and connect the light fittings. This is delicate, clean work.

Rewiring: The 18th Edition Standard

If your fuse box has rewireable fuses (bits of wire you wrap around a screw), your house is dangerously outdated. Modern safety standards (BS 7671: 18th Edition) require a much higher level of protection.

The Consumer Unit (Fuse Board)

The heart of the new system will be a metal-clad Consumer Unit populated with RCBOs (Residual Current Breaker with Overload). Unlike old fuses, RCBOs detect tiny earth leakages (like a child touching a live wire) and cut the power in milliseconds, potentially saving a life.

More Than Just Sockets

A full rewire is your chance to future-proof. Do not just replace like-for-like. Think about:

Data points (Cat6): Hardwired internet to every TV and desk.
5-amp Lighting Circuits: Allowing you to control table lamps from the main light switch (for that hotel feel).
Neutral wires at switches: Required for many modern "Smart Home" lighting systems.

Plumbing: The Pressure Problem

Victorian houses were designed for gravity-fed systems. A cold water tank in the loft trickled water down to the bath. This equals terrible shower pressure.

Modern living demands high-pressure hot water. The solution is the Unvented Hot Water Cylinder (commonly known by the brand 'Megaflo').

How it Works

We remove the cold water tank from the loft (freeing up storage space). We install a large, pressurised cylinder (usually 200-300 litres) that takes water directly from the mains. The water is heated by the boiler but stored under pressure. When you open a tap, the mains pressure forces the hot water out.

The Result: You can run two power showers and a bath tap simultaneously without a drop in performance.

The Lead Pipe Danger

In London, the pipe connecting the water main in the street to your stopcock is often still the original Victorian lead pipe. Lead is a neurotoxin. It accumulates in the body.

While Thames Water adds chemicals to coat the pipes and reduce leaching, the only safe amount of lead is zero. During a renovation, we strongly recommend digging a trench in the front garden and replacing the lead supply pipe with a new 25mm or 32mm MDPE (Blue Plastic) pipe. This improves both health and water pressure.

Heating: Radiators vs UFH

A new boiler needs a new delivery system.

Underfloor Heating (UFH)

Wet UFH (pipes in the floor) is the most efficient way to heat a large open-plan extension. It runs at a lower temperature (45°C) than radiators (70°C), making it perfect for condensing boilers and heat pumps. However, it requires a 100mm floor buildup and is expensive to retrofit into existing upper floors.

Radiators

For bedrooms, radiators are often better because they heat up (and cool down) quickly. Modern "Column Radiators" look like old cast iron but work with the efficiency of modern steel. Always oversize them slightly so you can run the boiler at a lower, eco-friendly temperature.

The Logistics of "Chasing"

To hide cables and pipes, we have to "chase" the walls. We use a wall chaser (a twin-blade diamond clutter) to cut two parallel slits in the brickwork, then Kango out the middle.

This creates an unbelievable amount of red brick dust. It gets everywhere. It is why we say you cannot live in the house. Even with dust extraction vacuums, the dust is pervasive.

Certification: The Paperwork

M&E work is legally regulated. You cannot just use a "handyman."

Gas Safe: The plumber must issue a Building Regulations Compliance Certificate for the boiler installation.
NICEIC / ELECSA: The electrician must issue an Electrical Installation Certificate (EIC) and notify Building Control (Part P).

Without these certificates, your home insurance is invalid, and you will face a nightmare when trying to sell the property.

Summary: Do It Once, Do It Right

Rewiring and re-plumbing are expensive, invisible upgrades. You get no visual "wow factor" for your money. But they are the foundation of a comfortable home.

If you mistakenly tile your bathroom before replacing the old steel pipes in the wall, and those pipes burst next year, you will be ripping out your new bathroom. Do the M&E first. Do it properly. Then enjoy the peace of mind for the next 40 years.

Frequently Asked Questions

1. Can I just add extra sockets without rewiring?

Yes, but only if the existing wiring is safe (PVC sheathed, properly earthed). If the wiring is old rubber or lead-sheathed, an electrician will refuse to touch it because adding to it makes them liable for the whole circuit.

2. Does a Megaflo require a new boiler?

Usually, yes. You need a "System Boiler" (which heats the cylinder) rather than a "Combi Boiler" (which heats water instantly). Combi boilers are great for small flats, but they struggle to fill a bath quickly or run two showers at once.

3. How long does a rewind take?

For a 3-bed Victorian terrace: First Fix takes about 5-7 days. Then plastered. Then Second Fix takes another 3-4 days. It is labour intensive.

4. Can I use wireless switches to save chasing walls?

Yes, systems like Quinetic allow you to place a switch anywhere (even on glass) without wires. They work via radio frequency to a receiver in the ceiling rose. They are great for listed buildings or feature walls where you don't want to cut the brick.

5. My water pressure is low. Will a pump help?

You cannot pump directly from the mains (it's illegal). You must break the flow with a tank (break tank) and then pump from there. Or, upgrading the severe lead supply pipe to 32mm MDPE often solves the problem naturally.

6. What is "testing and inspection"?

Before the electrician leaves, they "test" every circuit to ensure strict resistance readings. They issue a report ensuring the installation meets BS 7671. This is your proof of safety.