Well -- the wall is up! Will post pictures this weekend. In the end, I went the easy route. I had to get the concrete back porch pad replaced, so I simply had the guys pour the retaining wall as well. It's not perfect; it slopes somewhere between actual level and the slope of the sidewalk, and it's not really parallel to the street (the guy told me afterwards he simply ran a line from the outside corner of one neighbors wall to the other neighbors wall)-- but I don't think that will really be noticiable once I get the concrete stained and the beds put in and planted. I'm less happy about the drainage. I'd assumed he'd put in drainage holes; it looks like it's usually a piece of PVC pipe placed thru the form, and concrete poured around it. But they didn't put anything in. (This wall is about 16" high, and the space behind it is about 30 inches, with a drop of 12 inches -- hope that makes sense.) When the boss came by the next day to do the cut lines I mentioned the drainage issue to him, and he told me he was drilling holes at the base of the cut lines. They're small, less than an inch across, but they are spaced about every 3-4 feet. I know I need to put down gravel at the inside base of the wall, and a perforated pipe on top of that. Then more gravel and a layer of filter cloth on top of it before I put in the top soil. (And they're calling for extreme heat advisory for the next week!) A few quick questions: -- How much gravel above and below the pipe? Is 2" enough on both, or do I need more? -- After quick look at two box stores, it seems the perforated pipe only comes in a 4" diameter. This is a relatively low wall, with not much space behind it -- do I really need a pipe that big? If I don't, and I can't find a smaller one, can I use a smaller diameter PVC pipe and drill holes in it myself? -- The ends of the perforated pipe are open -- would it be smart to wrap the ends in filter cloth as well? -- I didn't actually see filter cloth at the stores, just read about it in a book -- but I have a done of weed barrier cloth I got on clearance. Can I use that, or do I need something plastic/fiberglass-like that will last forever? -- And since I'm buying more than just a bag of gravel and topsoil, is there a simple formula to turn inches into cubic yards? Appreciate all the advice -- once I get it stained I think I'm really going to like this wall, and it's nice how complimentary the neighbors have been about it -- since they're going to be seeing a lot more of it than I do!

Here is a shot of down the back of the lot with the yard area to the left. I would like the yard to basically extend to where the water is. It only collects water with heavy rains.

This project shows the difference between working with an installer vs a designer/installer. There's a pretty big disconnect between the two spaces. The plantings don't help - the looser textures and informality of the plants at the lower wall have nothing to do with the symmetrical plantings above. That said, I think you're left with an opportunity to do something kind of cool. I think if you add to the natural look of the lower wall plantings, and continue that idea around the perimeter of the lawn, and then increase the formality of the upper garden wall area a bit more, you create enough contrast that it looks intentional. Almost like coming out of the woods, or a meadow, and discovering a formal garden. If I were to do a path to connect the spaces I wouldn't do anything super formal or overworked, I'd do fieldstone slabs set level with the sod. I've seen projects on houzz where the only answer is nuke it from orbit and start over. Yours is not one of those. I think the right plant choices, thoughtful layout of a walkway, and some other minor tweaks will have you loving your backyard.

The comments here are very interesting, but there is not a lot of actual good advice. I built a concrete fence last year on the property line, so i actually do know the legal ins and outs about it. By-law officers showed up many times to check on things during construction. The first thing to note that is very important is that the neighbor building the fence, can apply to the city for a "right of access" permit at which point these is nothing that you can do to stop them accessing your property, depending on the city it usually costs about $250. these permits are very common and are normally issued for construction and maintenance purposes. however, that simply gives them the allowance to access a per-determined part your property and other specified things, like: to dig the trench. it does not allow ANY of the concrete to be on your property. the concrete can touch the property line, but cannot go over it. legally when completed they have to return your property to a similar or better state to how they found it, That's the Law. However, the real world is far more messy. There are a few things to consider here, ----------------------------------- The first to consider is the concrete footers, they are generally 5 feet below ground (where it freezes) and are needed to stabilize the concrete above them, they usually stick out 6 inches on both sides Now your can definitely stop them from putting any footers onto your side. BUT not having footers on your side can over time destabilize the wall, and make it move / lean / fall over / etc.. in the direction of the missing footer. remember ground is not rock, and it moves and shifts with time. So even knowing that you can stop the footer from being on your side of the property line, there is a very big question about what to do 5 years later when it starts shifting / leaning much more into your property... Personally i recommend, Negotiate! there are things that you can get out of this. ------------------------------------ Next is Fit and Finnish, the concrete that sticks out of the ground should be rendered to make it look nice. this will cost money, and so long as your neighbor doesn't do it on his side in the first month of two, he legally doesn't have to do it to your side, at all. this is considered the equivalent to him painting his side of the fence. ------------------------------------ Next is drainage, any concrete structure should be surrounded by a drainage pipe to help move water around the structure and stop water pressure underground from pushing on the structure causing it to move / fail. Again this will cost money, and legally does NOT have to be done. ------------------------------------ In Conclusion : obviously your neighbor can simply use the right of access permit like a big club to get what he wants. but at the end of the day, your neighbor will want you to be happy with the end results to avoid future problems. so Negotiate! let him build his concrete foundation, AND have the footers on your side underground. BUT mandate that he has to have your side nicely rendered, and place a drainage pipe on your side to make sure water will properly drain around this structure. ALSO mandate that you get to pick the look of the fence to sit above this concrete foundation. ----------------------------------- The last thing anyone want to to have to fight about how to fix anything in 5 to 10 years Here is a picture of my steal reinforced concrete fence. (it looks the same on all sides) (capping stones are waiting to go on the top, Covid-19 has delayed getting them on for months.)