I was leveling a wavy wall going up a staircase in my home using premixed general purpose mud. Took many passes and coats but I got it pretty good. I thinned the mud a bit with some water for a final top coat. After sanding I had some small areas that needed touch-ups. What I noticed is that with the spot repairs they looked shiny and very smooth and they were very hard to sand keeping them a bit raised with normal sanding. They even had a deeper gray colour to them. Any one know what happened here? I'm going to go after the spots more aggressively to get them flat but I would like to know what happened to cause the mud to dry so funny. Thanks

I've been getting bids to drywall my garage, and finally decided on a company. I emailed them this morning to ensure we were in agreement that the ceiling would get 5/8" rock (trusses are 24" o.c.), but he said he thought we agreed on 1/2", and that 5/8" would be $300 more. This seems ridiculous considering the ceiling only takes about 10 sheets and 5/8" is only $2 more per sheet. I realize 5/8" is a bit heavier, but they're using a damn lift and they are only 4x8 sheets. Should I fight him on this? And since when did companies start getting away with charging $75/sheet for drywall installation and finishing?