Just a quick bit of history. I'm a newbie when it comes to do-it-yourself flooring, so I tend to analyze the hell out of everything I'm doing so as not to completely screw it up as much as I'm capable of doing. I'm at the point in the process where I've got the carpet/padding/tack-strips/baseboards out of the room, and tonight I cleaned the slab where I'm planning on patch-leveling before I put down my engineered bamboo.

Since I had a clean open slab at my beck and call, I decided to take advantage of it with on of my other hobbies -- building radio-controlled cars. In this case, it's a drift car complete with lights. So out went the lights and on went the car, and as I was drifting lazy circles around the room, I noticed that the two LED headlights were revealing the true surface of the concrete in great detail. Where it seemed flat with the lights on, it now appeared wavy.

To advance this idea, I got a 7-LED battery-powered under-cabinet light, put it down on the slab, and it lit up even more area. It confirmed some low areas that I determined from using my laser level and taking readings on a 1-foot grid, but it also revealed other areas that need attention. Combined with my 7-ft piece of casing (which is actually straight), I can put it down and see where the light comes under and mark the beginning and end of the gap to map the low spots.

I was actually quite amazed at what a crappy finish there is on the slab, but I guess they figured that there was carpet going in so who cares.

If anyone's interested in pics to see what it looks like, let me know, and I'll try to snap a few.

I'm in the middle of floor prep now, on one that didn't look too bad....

600 pounds of mud later, and I still am not finished prepping the 1850 sq.ft slab. I ran out of mud, Friday. So today I hope to finish it up.

Ugh, that sounds horrible. I'm hoping I don't have to go to that extent to get my slab "flat" enough to put the flooring down.

I decided to use a product called Jasco Patch & Level, which is a ready-mixed product that comes in tubs like drywall mud. I figured this was a safer way for me to go since I'm doing this work on my own. It has a set up time of 4-5 hours instead of only 15-20 minutes like thinset, so it should give me plenty of time to work it around as needed while I learn the nuances of this activity.