installing new vent stack
i'm adding a toilet and sink to unfinished basement. both will be roughly 15' from main soil stack. i plan on installing a vent pipe just for the new fixtures, but due to layout, it would be easier to run the new vent stack up through the garage and out the garage roof. however, the garage roof is lower than the main roof of the house. my two questions:
1. can i install toilet 15' from main soil stack.
2. can new vent stack be at lower height than the main roof.
thanks ahead of time for your help.