We are thinking about splitting one very large bathroom into two full bathrooms. We’ll have to install another toilet (about 10 feet from the existing one and a shower). Are there any factors that could make this remodeling impossible? Thanks!
As RP said, a major issue will be the need for vents for the new fixtures. These will need to go through the roof and could be expensive to install. Local codes vary on the requirement, but so far as I know most codes will require a vent when you install fixtures 10 feet from an existing drain, as you describe. Another issue will be the need to properly slope the new drain lines. You will need at least a 1/4″ per foot slope for drain pipes. At 10′ that means that you need 2.5″ vertical offset of your drains. This may be a problem, depending on the space you have in the floor joists to install the drain pipes. I once did a job like yours and had to install the added fixtures on a “platform” to meet the slope requirements. This was an ugly solution, but it was necessarym and the client was willing to live with it.