Venting for new bathroom

we are installing a new bathroom on the main floor of our old house. There is an existing 4 pc bathroom on the second floor and we have access to the vent and drain pipe to that bathroom from down below but the 2nd floor bathroom is (a) complete and (b) occupied by our tenants. My question is:

Can we tie our venting from this new bathroom into the existing vent pipe below the 2nd floor ? I have read that you can only do that if there is no drain above where we want to tie in and don't understand that statement; of course there are drains above.

The toilet will be about 15-16 feet on a 45 degree angle to the vent pipe we have access to and can cross the ceiling as we are putting in a new ceiling in the adjoining room.

Also in our basement there is a black PVC pipe with an orange cap with the word VENT on it - is there any way we can use that?

Thanks. Glad to find this forum.

Miriam

You should be able to tie into the waste line for your new stuff, but you can't use a waste line as a vent. You might not need a new vent all the way through the roof, but you need to connect to the existing one above the drains of those above you. The general rule is 42" above the flood rim (say the sink upstairs was at 36" for a kitchen counter, you couldn't tap into their vent until it was at least 42" or 6" above where it could flood). It might be easier to make the connection in the attic, or make a totally new run all the way to the roof; can't tell without being there.

If the plumbers properly pre-plumbed in a vent line, and work above it has not compromised it, then you can use that as your vent. Again, can't tell without being there. Can you take a picture and post it of the vent? Does the pipe labeled vent continue down, or does it just terminate? If it is just terminated, it probably could be used. When you cut the cap off, make sure you have a bucket as it could be full of stagnet water that accumulated from condensation and rainfall...it could be quite gross.

vent

I take it you belong to the "anyone can do plumbing" group, but you do not really know what you are doing. There will normally NOT be a connection to the second floor vent in the first floor.

Plumbing Bathroom

Its hard to get an idea without a pic, but is this a full bath or only a powder room? You might could look into Studor venting it.. Not something that would be ideal, but its an idea.

Ahhh yes... The studor vent... One of my all time favorite things...

HAHA! Thats the new model isnt it..

Aav

AAV's are not ideal solutions for downstairs plumbing which will be subjected to positive pressures.