I am in the process of adding a toilet to a former porch/pantry in an older home and was wondering if the toilet vent height needs to be at the highest point of the roof, or can I vent it through the roof of the porch/pantry. There are a number of windows on the second floor and I do not want to vent it incorrectly.

Thanks for your help,

Tim King

You can't vent from the lower roof line. Check you local building inspector to see if they allow an AAV instead of a vent. Your other option is to try to connect to the existing vent stack if you don't have to tear down the house to get to it.

Bob's correct. Sections 1404.4 and .5 Of the Standard Plumbing Code, (Extensions Through Wall) allows you to extend vent terminals through a wall providing that,
1- No vent terminal shall be located directly beneath any door, window or other ventilating opening of the building.
2- No vent shall be located within 10 feet horizontally of such a opening unless it's at least 2 feet above the top of such opening.
In short, you may connect to a existing vent out the roof but you ncan n ot vent from the porch. Regards, Tom