I've excavated my PVC sewer lateral, am about to get a City permit to patch it (with Fernco couplers with stainless steel bands), and after digging that frickin hole I sure want to do the best job possible that will last a few decades.

A friend says he paid a sewer repair guy to not only patch his sewer line, but also create a cement wall next to the patch to block roots from the nearby tree. I don't know what that barrier actually looked like ... it seems like it would have to start a few inches below the pipe and extend up near the surface. Have you seen such a thing installed, how was it done, and do you think it's a worthwhile effort? I can't find any info about such a thing on Google.

if the job is done properly, no roots will get into the pipe. if you are concerned use 4 band clamps for added strength.

You don't REALLY believe a simple wall would stop roots from reaching the pipe do you? Pour the concrete around the pipe if you are really worried about it.

if someone believes the roots will find their way thru a properly tightened 4 band clamp, then the roots will certainly find their way between the cement and the pipe.