Sealed a 10’x10’x38’ air handler that would not pass the inspection because it could not hold pressure.
Lined a 4” copper pipe that was heavily channeled out on the bottom 40’ from rod out station to rod out station. No need to dig!
Video inspection of underground air ducts. Ducts are metal and extremely rusted. Suggest Trenchless Casting to spin cast a new concrete pipe inside the old pipe then spray lining the new pipe with Duct Armor Duct lining material.