Gas leak detection & carbon monoxide investigation

If you can smell gas, ring the National Gas Emergency Service first on 0800 111 999. Once the supply is made safe, we trace the escape, test the pipework and put it right. We also investigate carbon monoxide: a sounding alarm, a yellow flame or sooting around an appliance all point at combustion that needs testing properly.

Covering North & Northwest London and the Hertfordshire borders, from our base in Colindale.

A thermal imaging camera reading surface temperature

When people call us about this

  • You can smell gas
  • Your gas meter is moving with everything turned off
  • A gas appliance keeps going out
  • Sooting or staining around an appliance
  • Your carbon monoxide alarm has sounded, even once
  • A boiler flame burning yellow or orange instead of blue
  • Headaches or drowsiness that ease when you leave the house

How the job runs

  1. 01

    Make it safe first

    If you can smell gas, ring the National Gas Emergency Service on 0800 111 999 before you ring us. Open the windows, leave the property, and don't touch switches. That call is free and answered 24 hours.

  2. 02

    Tightness test the system

    Once the supply is safe, a tightness test across the installation tells us whether there's a leak and roughly how big it is.

  3. 03

    Trace, repair, re-test

    We section the pipework to narrow down where the escape is, make the repair, and re-test the whole installation before it goes back into service.

  4. 04

    Test combustion for carbon monoxide

    Where CO is the concern, a flue gas analyser reads what the appliance is actually producing. That measurement, plus the flue and ventilation, is what tells you whether it's safe — not how the flame looks.

From real jobs

Questions we get asked

I can smell gas. Who do I call first?
The National Gas Emergency Service, on 0800 111 999. They're free, open 24 hours, and they'll make the supply safe. Call us once you're safe and we'll find and repair the fault.
What does gas smell like?
Natural gas has no smell of its own, so a distinctive rotten-egg odour is added to it deliberately. If you can smell that, treat it as real.
My meter is ticking over with everything off. Is that a leak?
It can be. A tightness test will confirm it either way, and it's a quick test to carry out.
My CO alarm went off once and stopped. Should I still call?
Yes. A single activation is enough to warrant a proper investigation. Carbon monoxide has no smell and no colour, so the alarm is the only warning you get, and it doesn't sound for nothing.
Which appliances can produce carbon monoxide?
Anything that burns fuel: gas boilers, hobs, fires, water heaters and solid fuel appliances. Incomplete combustion is the cause, and any of them can do it if something is wrong.

Areas we cover

We cover 17 areas in total. See every area we cover.

Other things we do

24/7 emergency callout

Gas leak detection & carbon monoxide, priced before we start.

Gas Safe registered, 12 years in, and rated 4.8–5 stars on Google and Checkatrade.

07525 379063Request a callback