The problem may be elsewhere. Being that you say it is the Hot water that is the problem, have you looked at your hot water tank recently?
- Is there water by the over-pressure vent pipe?
- Do you have an expansion tank that may be bad? Tap on the tank with a screwdriver. Does it sound hollow? If so this is normal indicating that air is inside the tank. If it sounds solid, than the internal bladder has probably ruptured and the tank is filled with water. This means there is no where for the hot water to expand to and therefore the pressure in the hot water lines has increased. Your shower hot water faucet could be the weakest link, showing a problem there first.
Pressure relief tanks get connected in the cold water pipe, by the water heater. When the hot water heater runs, the hot water expands increasing pressure. Before expansion tanks, this pressure was allowed to build up in the water main, and back to the utilities main. This started to become a problem for utilities with the added pressure from all neighborhood's houses. So someone came up with the idea to add expansion tanks within the home. These tanks absorb the increased pressures, so that the fixtures within the home only see a steady regulated pressure, and the main stays constant pressure.
Try running cold water in a nearby sink while looking at the troubled hot water faucet. If if stops leaking with the sink running, that should give an indication of it being a pressure problem.
In any case, I would start with measuring the water pressure so you can determine if it's a pressure problem or just a faucet fix.
Could be you need an expansion tank. Can you measure the water pressure? Big box stores sell cheap pressure gauges for ~ $10 - look for it in by the irrigation plumbing. You can hook it to your outdoor hose bib, Wait for the water tank to kick in and heat the water (or when the faucet shows a leak) then see if the cold water pipe PSI increases.
By me, all new housing has to have an expansion tank.