95 E320 Heat Shield
 

While driving, a large section of the heat shield fell off. I checked under the car and what remains is around 40 % of the top of it still in place is very corroded condition.
Is this a replaceable part?
On other cars when the heat shield rattled, mechanics told me to just cut it off and don't park on tall grass. When I asked if they can weld it back in place they said there was nothing to attach it to.
I am mostly concerned about heat coming back up at the underside of the body floor.