Delivered to the curb by The Wall in Portland OR. This company recycles concrete from sidewalks, parking lots and driveways into building materials, and also offers complete chunks as we ordered here. The concrete for our 3' by 60' path was in chunks typically 1-3' across and 6-8" thick. The 2.5 cubic yards costs us $120 delivered and yes we have a pile left over :0. We will continue the path into the back garden next spring.
Your path design is limitless, but the 'trough' you dig should be about 1/2 again as deep as your concrete chunks are thick and the floor of the trough should be as level as possible.
You are digging more than you might think to get it nice and deep enough. All the dirt on the right (and then some) came from the trough.
After the path is dug, you fill in with a level floor of sand laid in at a depth of about 3/4 of the average thickness of your chunks. This sand will allow you to level the path, provide very good drainage, and serve as the 'dry mortar' that holds all the chunks together.
I described the dimensions of the path to Action Sand and Gravel and they told me we needed 2 cubic yards. This was about $90 delivered and they tell me that it probably weighed about 7,000 lbs :0 (it was wet most of the time I was dealing with it).
We did not need quite that much. Get the square footage of your path, figure how deep you need the sand, and get your volume figure and then translate that into cubic yards. A path this size probably needed 1.5 yards. The thicker the concrete, the nicer the stability of the path, and the deeper your trough - which means the more sand you'll need.
Depending on how much moisture you get, you should avoid plastic or even cloth weed guards laid in the bottom of the trough if possible, as they will impair drainage.
Beginning to fit together the puzzle pieces. Experts (like my dad and his dry-stack wall guru mentors) say to not start at one end and build your way down, but instead lay 'good' pieces in different areas along the path and work from there. In this case, we built out the 'entryway' of the gate as one of the sections.
As the chunks are puzzle pieced together, you are constantly moving sand to allow a good base beneath each new piece, and enough sand to slide a berm in front as you push it up against the already set pieces. This berm of sand makes a joint between the pieces. It is very important to not fill these joints in with dirt or mud, but only sand as it drains water so well and mud will repel the water and create puddles.
The joints can be filled in with plants that are good for being walked on and those that will withstand your specific climate condition. A good resource is Steppables and they recommend things like creeping thyme.
If possible, plant in sand, and allow soil to naturally occur in the joints, but avoid filling in the cracks with dirt, as it will not drain and does not sweep clean like sand.
We have covered our back lawn with old carpeting from a neighbor's remodel. Before we laid down the carpet, we pumped the lawn with nitrogen, and then we covered the carpet with a thick bed of fallen leaves from around the neighborhood. Over the winter, the lawn will be turning to mulch.
The plan is to remove the entire lawn without chemicals, and then build out more sustainable (and enjoyable) gardens and more paths, and some new trees, next spring and summer. More on lawnsagna later...
