I have broken open the walls behind both the front and back of the built-in tub there are n o shut off valves where the water enters the faucets. Right now I have just about demolished the bathroom with the crowbar and the hammer - I need more patience - but ? Is it possible that they don't exist - the toilet and sink have their own shut offs and neither ones affect the tub. Thank you

Have you looked for them in the basement?

What do u need shut off valve for? Do u have a leak?

Some tub/shower units have a shut off built into them. It is a screw that is located below valve.

One of the plumbers on site may be able to give u better location.

Chuck