I have gone through several iterations of screeding across laser-leveled wood forms. The results have not been pretty: i've had to rake down high spots and do have some low spots that will subsequently need to be filled by the self-leveler compound. But the latter is very expensive and the overall time and product are not acceptable.
It seems that screeding by oneself is actually not considered to be particularly easy. Here is one resource Masonry and concrete Screeding
Screeding With an Assistant
Working with an assistant is critical for perfect screeding. If not, you're kneeling in the sand layer ahead of the screed tool. The screed tool will help to smooth out your knee and shoe depressions. But it's best not to kneel in the sand in the first place. When you work with an assistant, both of you can remain outside of the project area.
In addition, screeding tools can be hard to handle. Screeding a 3-foot-wide walkway is manageable by one person. But when the screeding tool is a full-length two-by-four (8 feet or even longer), it is very difficult for one person to effectively handle the tool. You'll need two people—one at each end—to control this heavier, larger tool.
Now I've seen videos of folks doing an excellent job by themselves. But my opinion is that they're gifted at this and their approach is not directly replicable by myself.
Some of the things I've tried:
use a wetter pour. This helps but then it is also not recommended due to the possibility of excessive water molecules being embedded into the concrete thus weakening it.
level level level again as the concrete is laid out. This just did not go well: I was not able to achieve a consistent level even giving an excessive amount of attention to it
[not tried]: Use small width forms, say 36 to 40 inches (about a meter). This would certainly make the screeding easier but that's too much work.
The 2x4 (possibly with attached handles that I screwed in) could not stay flush with the forms. I just could not make it happen. Probably mostly due to asking myself to apply more force (across 6+ feet / 2 meter or so) than I can muster. But there must be more to it here; I'm missing something technique-wise
There ends up being waves in both directions (parallel and perpindicular to the forms)
Another aspect of the challenge is that in the heat of battle - with the concrete surrounding me in all directions - I get nervous about making a mess of it. I have tried out those spiked concrete shoes - which don't help almost at all vs regular boots (and add to the situation constant opportunities to twist an ankle when carrying/lifting 60 lb / 27kg bags and manuevering 300+ pounds / 135kg of concrete in the wheelbarrow). Throwing thin plywood floating sheets on the concrete works better but the waves tend to take advantage of that situation to hide themselves underneath.
My current thought is: "well I'm basically giving up on the single-person-hero approach to screeding" so then the options are:
- insist on finding a partner to work that 6 or 8 foot (2 to 2.6m) screed with me on either end
- get a moderately pricey power screeder to help out
I would like not to depend on having someone else around so I've identified a moderate priced screed/vibrator tool. But even with that in place I suspect things will go better but still not "smoothly". I'm missing something here, and am soliciting tips on how to force the concrete fix into "behaving" level wise.