Outdoor stopcock frost protection

[klang]

My elderly dad died, and I'm looking after my mum's house for her.
There are some outhouses with their own water supply.
This is a copper pipe rising directly from a concrete floor in a draughty outside loo, with the stopcock about 4 inches above the floor.
The piping to the loo, and onwards to a sink and washer is insulated, but the 4 inches at ground level isn't.
My dad lit paraffin lamps in three affected places for decades, but I can't continue with this tradition.
I plan to turn the water supply off on winter nights, and drain the pipe at the sink.
This leaves the four inches of uninsulated pipe at ground level to worry about.

Should I get this insulated?

And to what depth should I get it insulated?

And what should I use?

Thanks in advance.

 

[blup]

If you partially drain the pipes there may be sufficient space for the water to expand without bursting the pipe. A wet and dry vac will suck the excess water out. Otherwise wrap with hessian pipe insulation, much easier to fit snugly than the split pipe foam alternative imo. But be aware a cold outside spot with standing water in the pipe will probably freeze.

Blup

 

[stem]

If by "washer" you mean a washing machine, there will be an electricity supply. So, how about a small tube heater. They start at about 40W and if wired through a frost thermostat it will only come on when there's a risk of freezing.

Not sure why all of the pipes are insulated except for the 4" section at ground level that you mention, but if you can insulate it you definitely should. If its too close to the wall or ground to slide pipe insulation over it, you could box it in and fill the box with loose insulation.

You can also get insulation covers specifically for stop taps.