Loop-cut won't go all the way around Alright so I've seen some postings about loop cuts and done some research. I am very new to blender and modeling overall. I am trying to loop cut this concrete barrier. Now I'm following a tutorial and kind of did my own thing in some areas. I cleaned it up following some instructions in another answer here on stack exchange.

I can't for the life of me figure out why I can loop cut around the whole bottom:


...but not the whole middle:


I see this marked as answered by another question. That question refers to ngons and inside faces. Now once again I'm totally new to this. I looked on the inside. I don't believe I have inside faces or any ngons by the terms I've read online in my research.

Here is a wireframe picture and the inside view:




Maybe I'm missing something the answers on other posts are saying. If so and you know what it is I'd be very appreciative of what it is.
This is because the bottom face doesn't have the proper geometry, the edge ring tool doesn't know where to direct the ring since there are several vertices (it is an ngon). You can only use this tool on quads (4 sided faces). So to fix, you can use the knife tool and rework the ngon into a large quad.



Additionally, there is also another problem, you have duplicate vertices at the point where the cut stops. To fix, first box select (B) the points shown below and use Alt + M > At Center to merge the duplicate points into one.



After you do that, use the Knife Tool (K) to create a quad as shown below. Press K and select one vertex then another and press Enter. Repeat for the other side and you should be able to add edge rings after.