First Fix & Second Fix Plumbing Guide

Plumbing in a house is an integral part of the everyday use of your home. From bathroom toilets and showers to kitchen taps and washing machine pipework, no house can flow without it.

First-fix and second-fix plumbing will be part of the planning process if you are building a house from scratch or undergoing significant renovations.

They're both critical parts of planning and implementing a home, but whether you're trying to keep costs down or do as much as possible yourself, you need a good understanding of both stages of the process.




When carrying out your own plumbing work, you should wear waterproof clothing. Safety shoes are required to protect your feet, and if you’re cutting or working with other power tools, you should wear a dust mask, protective eyewear, and work gloves.

Any PPE you need for DIY can be purchased direct from Speedy Hire.


First Fix & Second Fix Plumbing Differences

First-fix plumbing is as it sounds. These are the jobs which are done either before or during a house build or structural renovation. So, this includes:

  • Laying the pipework, including underground
  • Wastewater pipework
  • Pipework behind walls

The above needs to be carried out by professional plumbers who know what they are doing and the rules around water supplies, drainage, and how a house works. Most will work with electricians to ensure everything is where it needs to be.

The second-fix plumbing takes place when the structural work has been done. By this stage, the pipework and fittings should all be in place. In a way, this stage of work makes a house habitable or adds finishing touches.

The work includes:

  • Fitting a boiler and radiators
  • Fitting bathroom plumbing (such as toilet, sink, shower)
  • Fitting kitchen taps
  • Connecting water outlets (i.e. for dishwashers and washing machines)
  • Checking plumbing

Some second-fix plumbing jobs can be carried out by a confident DIYer. This could save installation costs and reduce the time frame professionals are required on your site.

After the second-fix plumbing is complete, you're generally ready to undertake the finishing touches of your home, such as painting, tiling, and flooring.

Before confidently carrying out your own second fix plumbing, you must ensure everything is correct for you to work with. This means pipes and waste pipes are in their proper place, you have a shallow waste bath trap, and your chosen appliances suit the space (i.e. you have the correct length hoses).


Is there any plumbing which I can't DIY?

Don't think you can do all of the second six plumbing yourself.

We would not recommend installing your own boiler. This requires someone on the Gas Safe Register with knowledge and training in plumbing and electrics. Under Building Regulations, you can only register a boiler through Gas Safe.

It is, therefore, illegal to install your own boiler. You can read more in this guide on boiler installations from BOXT.

Aside from this, you're free to install most things yourself. You'd do this in the same way you'd maybe try replacing your sink unit, taps, or toilet cistern. Items like washing machines can usually be installed yourself.

But make sure you know what you are doing. If something isn't right, water can cause structural damage to your home, which could be an expensive mistake. If you have any doubts, get the professionals in.

In most cases, plumbers and electricians who carried out the first fix work will be happy to see the project right through, but this isn't a necessity, so shop around for quotes.



Whether you need tools to add the finishing touches to your house or are going to try second-fix plumbing yourself, we have thousands of power tools and plumbing tools available to hire.

Hiring is ideal for short-term or one-off jobs when you need tools you won't use in future. No storage, no high upfront costs, and no need to sell equipment.

You'll find all the power tools and hire equipment you need here. Why not start planning your next DIY project and open a Speedy account online or on the app for all your tool hire needs?

Speedy has more than 200 local service centres nationwide, hire counters in selected B&Qs and nationwide 4-hour delivery. It has never been easier to hire the tools and equipment you need.


For more tips, subscribe to our YouTube Channel

Find ideas on Instagram.

Speedy in your pocket
Get a Speedy Account