double walled gas flue pipe and a hole to run the pipe thru. any lowes store or hardware store carries it and can tell you exactly how to do it
Depends on what type of vent system water heater has.
When you cannot use B vent to find a way to vent the HWT through to the roof!
YES
B-vent pipe.
Because of the carbon monoxide produced from the burner at the bottom that would build up and kill you.
a direct vent water heater is more fuel efficient (cost's less to operate). aside from that there isn't much difference, aside from not needing a double wall flue through the roof on a standard gas water heater.
Check the code for your area. Most I have seen go through the ceiling.
You need to put the roof into vent position. After it is in the vent position push and hold the vent button again until the sunroof gives a little movement. After that happens the roof should run normal.
A roof vent can be blocked by hoar frost and to illimate this phonimia you need to increase the vent terminal to 4" If a vent terminal is blocked by leaves or other soft debris the water jetting is one of the best ways to clear it
Generally there is no need for a roof jack in a porch roof. If the porch ceiling will be covered you could run a vent through the roof.
In plumbing the roof vent should be a min of 4" to prevent hoarfrost
You should not have to clean a vent on the roof. unless you are trying to clean the waste line to the fixture below. Then you would send plumbing rods through the vent on the roof.