Old stack vent system vent tub
I wrote in another thread about my slow draining tub.
The consensus is that I need a vent, preferably downstream from the sink ( many mentioned an AAV just beyond the trap) now my issue is that I have a pedestal sink, and the plumbing is not really accessible around the sink to put in any kind of vent (without ripping up tile and what not).
I have easier access to the area under the tub, near the drain. My question is how would I go about installing a vent here, say just beyond the tub drain trap maybe? I know it needs to be a 45 degree bend at least off the existing drain pipe, but since it's a tight space (with the tub in the way!) can I run some horizontal vent pipe a few feet, and then go vertical to the attic and join the main stack?
Or is this a bad idea altogether?
Thanks in advance for your help.