Originally Posted by kerrbe
How did you lower the high spot?
I used a 4' bubble level and mapped out the high spot like a topo map. Then I went at it with a oscillating tool to kind of surface skim and chisel the particle board to an approximate level -- darn stuff has no grain -- and finished with a belt sander with coarse grit -- 36 or 40, iirc. Some of it was under the slide. I have an air powered "cheese grater" (think body shop air-plane) sander that I could run underneath the slide once I tipped the slide up. The wood stank of water seepage and chemicals. I kept the fan going, a bag on the sander, and wore a mask and face shield.
Little rips past the deck height weren't an issue, since I smoothed it all with self-leveling compound. It isn't perfect, but especially with a bit of padded rubber mat to stand on I can't feel it anymore. It wasn't a complicated job, but it was tedious. Wear knee pads.
 I forgot -- my high spot went into a low spot where the roller sits. I did a primary fill of the low spot with a PINT of fiberglass resin and cloth in layers. I followed that with some bondo to get it closer to level, and then applied self-leveling compound. I capped the area with a piece of sheet metal. I don' think the roller is getting through all that.
It was a December project. The best part was that I bought a carton of 20 N-95 masks and a couple 100ct boxes of blue gloves for the 2-mask/10-pair job. They're coming in handy.