sewage backup, cleanout cap HELP !!!

I recently had sewage back up from my toilets and showers. I live in a house built in the 1960s and it didn't have a cleanout cap. On the advice of my plumber I had one put in in my front yard (where the metal pipes exiting the house connect with the clay pipe which exits to the main sewer line in the street). After the cleanout cap was put in , the plumber snaked the main clay pipe and found no roots clogging it. He said there were roots right where the metal pipe connected to the clay pipe and removed those roots. My plumbing worked fine for a few weeks, but today I again had sewage backup in my toilets and showers and some overflowed out of the clean out cap. The sewage backup seems to happen when the clothes washer is draining and somebody is flushing the toilet or taking a shower at the same time. Anybody have any ideas?? Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes, there is still a partial blockage somewhere past the cleanout since that is leaking also. . Maybe old, maybe new, but it is definitely blocking up. If not in your line, it is in the main line.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Edwin Pawlowski wrote:

Agreed. And it may take a video cam in the lateral run to find out the real cause. See if the guy who did the work will co-operate to find what he missed.
Jim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sure it's actual clay pipe, and not that weird orange fiber stuff (can't remember the name) that looks like clay? Symptoms sound like a partially collapsed line. On a house I own that had repeated problems, I finally said the hell with it and replaced the orange stuff with plastic, all the way to the line in the street. No more problems. Life is too short to worry about having a working place to take a dump, bite the bullet and never have to think about it again.
aem sends...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.