Moving plumbing around - what to think about

An example of clean concealed plumbing Credit @bathroomdesigning

Whether it is part of a larger project or just much needed improvements. Moving plumbing around in your property is common work due to the benefits it provides. In this article we will discuss the main points to consider when planning plumbing works, including rules of thumb and things to avoid.

1. Know the common sizes for different pipes.

plumbing bathroom

Pipe sizes can affect what can be moved and to where Credit @ApartmentTherapy

Pipe sizes will differ in diameter depending on its intended use. Most of the time, these alone will determine the best paths certain water services and foul runs should take.

What are the standard sizes of plumbing piping?

  • The WC foul / soil pipe - 110mm

  • Sink and other foul pipes - 40mm

  • Hot and cold water pipes - 25mm - 32mm

As can be seen above, the WC / soil piping is the largest and most critical item to locate correctly. This normally determines the optimal layout and design for your plumbing.

2. Try to incorporate the ‘Stack’ method

More often than not it helps to have any rooms using plumbing to be located next to each other either horizontally or vertically. When these spaces are located in the same place above one another, it is referred to as the stack method.

This method allows for shorter distance that water supply needs to reach each appliance and means fouls runs can connect and continue to fall to the ground level without the need for bends etc.

3. Be conscious of how piping will pass through walls and floors

raised bath

a bath will need to be raised to pass pipes in certain circumstances Credit @buildingour_amalfi

As mentioned before, the 110mm WC / soil pipe will normally determine what is possible and which direction a foul run should move towards. 110mm is a large size to run within floors or underground for instance and are normally taken externally and down to a manhole via. a Soil Vent Pipe (SVP).

Be sure to plan for the foul run to exit out to a SVP with the least amount of intersections with walls or floors.

4. Try to use gravity

Following on from point 4. it is important to accommodate falls in any foul pipework, so that waste can exit freely. This usually means the following when designing and planning your plumbing.

  • Make sure foul runs are as short as possible

  • The use of SVPs make the use of gravity simple once foul pipes connect to them.

5. Use existing manholes where possible.

New manholes will need to connect either to an existing manhole or to the public sewer Credit @down_intown

Once the foul run reaches the SVP, it is key that the foul continues to an existing manhole externally where possible. This will avoid any requirements for additional permissions and works. Where this is not possible, make sure to consider the following.

  • New manholes will need to connect either to an existing manhole or to the public sewer.

  • Where connecting to a public sewer, a public sewer connection application will need to be made.

  • If building any works within 3m of a public sewer, a build near / over agreement may be required.

  • If the location of your property means you do not have access to a public sewer, you made need a septic tank or a similar solution.

6. Reduce hot water pipe distances where possible

Hot water pipes lose heat quite rapidly when containing hot water from a boiler or hot water cylinder. This can quickly mean the needless loss of energy, slow times for hot water from taps and more potential areas for risky leakages should a pipe fail.

Some ways to keep hot water pipes shorter include:

  • Locating the boiler close to plumbed rooms.

  • Using the stack method.

  • Laying out plumbed rooms so that piping takes a direct and short route.

7. Try to include plumbing in areas which are easy to conceal

hidden plumbing

An example of how concealing servicing can be done with cupboards Credit @bathroomdesigning

Unless it is a particular design feature for your project, it is normally ideal to conceal servicing to keep a clean and uncluttered aesthetic for your project. Some popular ways to conceal your plumbing include:

  • Hiding piping behind cupboards and joinery.

  • Keeping piping along walls at low level.

  • Boxing in soil pipes in the corners of walls


8. Try to locate plumbing in areas which are easy to maintain

While concealing is key to creating a clean uncluttered environment. It is also important that the piping is easily accessible for maintenance and repairs. Some easy methods to ensure this include:

  • Piping covered by joinery contains doors and open backs.

  • Piping within wall boxing contains a hatch or an easily removable panel.

Keep plumbing simple

Plumbing - as seen above - is best kept simple. Whenever considering plumbing, whether moving plumbing or a complete overhaul of an existing system. Always try to keep as simple a layout as possible.