Jeffery Jones wrote:
After reading that Washing machine hoses, etc are statistically the
biggest cause of flooding, I would like to prevent this.

I currently have a standard washing machine wall box with 2 standard
multi-turn boiler water valves. I would like to retrofit a single
lever dual-valve shutoff in place of the 2 standard valves.

The house is about 10 years old, but I have no idea if the valves
are threaded or soldered in place. I'd have to rip out the drywall
around the Washer box to either hold the nut to unscrew the old valves
or to be able to unsolder the old valves.

1.) Is this a good idea?

2.) Could a plumber do all this including cutting out the drywall,
etc?

3.) What about a no-construction jackleg sort of solution which
would be 2 hosepipe-to-1/2"-adapters so that the dual-valve would be
installed outside the boiler valves?

Installing a single control valve won't prevent
anything. You need to turn valves off each time
you finish using the washing machine. If you
can't do it now with two valves, you won't be able
to do it with 1 valve.

If you really want to prevent possible flooding
you need to install solenoid controlled valves
that are normally shut and only open when the
washing machine operates. The solenoids probably
needs to be controlled by circuit of the main
timer/main control.