Venting Issues

[RPWolf]

Looking for advice to help guide what help I need to resolve. I have what I think is a venting problem with my home. Every few weeks my kitchen sink will backup and not drain correctly. If I run the disposal, it pushes all the water into the other side of the side-by-side kitchen sink. I then have to run several sinks and flush a nearby toilet and then the sink will drain. Seems like an air pocket is forming in the kitchen line - which also has several other sinks tied into it. Everything runs great for a few weeks then repeats. I've had the drains cleaned and the main drain snaked, no issues found making me think its a vent issue. I have 5 1/2 baths, 10 sinks in the house. All appear to tie into same vent. Wondering how best to troubleshoot? Do I need to find someone that is willing to get on roof? So far plumbers have avoided that.

I've also seen several posts about solar-fan vent caps - would this help?

Thank you!

 

[WorthFlorida]

When the drains were snaked, a camera should have been used. It could be with all the years using the disposal, crud might have worked up the vent pipe, however, a good flush and running water clears things up.???

 

[Sponsor]

 

[John Gayewski]

We're sure the sink pipe is stopping the water and not the disposal splash guard?

Next time it acts like it's slow, push the flaps of the splash guard open with your finger or a spoon or whatever.

 

[Reach4]

If you eliminate the splash guard as the cause, lift out the splash guard. Pour water from a bucket rapidly down the disposal. See how much water you can pour quickly before the water rises on the disposal bottom.

From that we can estimate how far away the clog is.

It is common for sink drain lines to clog where the flow turns from vertical to horizontal. This could be below the basement floor.

Was the drain snaking professionally done with a big machine?