Connecting to taps on baths, hand basins or sinks

This page applies to ½ and ¾ inch taps (including 2 hole mixer taps) - see our other page for Mono block (single hole) mixer taps with 10mm connections.

½ Inch taps are used on hand basins with 15mm pipework while ¾ Inch taps are used on baths and sinks with 20mm pipework.

When fitting a new bath, hand basin or sink, there is no standard for whether the hot tap is on the left or right, however:

  • It seems that in Southern UK, the hot tap is 'by tradition' on the left, while in Northern UK it is on the right.
  • It is probably a good idea to be consistent within a property.

The parts required

tap connection - compression fitting
tap connector - soldrr fitting Solder
tap tail adaptorTail

To make the water connection to the taps, pipe to tap fittings are required; these are available in both compression and solder type fittings - both having a fibre washer with a screw fitting to secure to the tail of the tap.

It is good practice to have a compression joint within a short distance of the tap in case it needs to be removed in future - using a solder joint tap fitting with a compression pipe fitting further down the pipework does have the advantage that access to the compression joint will be easier.

When replacing taps, the new taps may have shorter tails than the original ones; in this event, fitting short tail adaptors to the taps may avoid the need to adjust the existing pipework.

Bendable pipe for connecting tapsTo make the job of bending the pipework between the supply pipes and the taps easier, flexible pipes are available. The two common types are hand bendable copper pipe (as shown right) or stainless steel braided type. The former normally has a plain pipe at the bottom which can be joined using either a compression or solder fitting; the stainless steel braided type normally has compression fittings at both ends.

Shut off valveIt is worth considering fitting shutoff valves (as right) in each supply pipe under the unit - these are especially useful where the feeds are from storage tanks as future repairs will not require the tank(s) to be drained.

Making the connections

Connection to taps Making the connections to the taps before the unit is in place is often easier as access to the tails of the taps can be very restricted once the unit is in place. It may be necessary to put the unit temporarily in place to establish the lengths and bends for the pipes.

If using solder tap fittings, make the joint to a length of pipe (without the fibre washer in place) before fixing the fitting to the tap.

Likewise with compression tap fittings, it is easier to tighten the joint onto the first piece of pipe 'off' of the unit.

To fit tail adaptors:

  • Wrap two or three layers of PTFE tape around the thread of the tail of the tap, go in the direction of the thread.
  • Apply a thin coating of jointing compound to the threads of the adaptor.
  • Screw the adaptor onto the tail of the tap and tighten using a tap spanner (if necessary) and a spanner or stilsons.

To fit the tap fitting to the tap:

  • Wrap two or three layers of PTFE tape around the thread of the tail of the tap (or the bottom of the tail adaptor if used), go in the direction of the thread - make sure that the tape is kept away from the seat for the fibre washer.
  • Always use a new fibre washer, fit it onto the flange around the top of the connector.
  • Push the connector into the tail and hand tighten the nut.
  • Use a tap spanner to tighten the nut onto the tail - grip the body/spout of the tap to make sure that it does not turn on the unit as the connector is tightened.

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