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.
4" diameter to prevent hoarfrost and depending if the roof is used for weather protection or promenade deck how high the vent terminal ends Weather protection 2 feet above the roof Promenade 7 FT plus it must be kept away from vent intakes or windows or adjacent buildings CHECK local codes
Yes. The roof vent is usally located on the roof. If the vent is clogged, it can create numerous issues and prevent your plumbing system from working properly.
Yes, the baffle is choking off the vent, causing the toilets to flush slow.
Do not ventilate your roof by yourself as you can make many mistake and cause irreparable damage to your roof. Always hire a professional to do the work they are experienced at, especially a roof.
YES
There are many places that one could purchase a roof vent kit. One could try a website like Amazon or one could try a store such as Home Depot or Lowes.
Yes you can get a high wind cap for the vent.
A vent Terminal and depending if the roof is strictly for weather protection it terminates about 24" above the roof. If the roof area is for people then it is 7 ft above the roofing surface.
About 3 feet, but if your not going by code, i think you could go 4 feet and be ok
Vent through roof