We're planning to put down a floating floor. We have a concrete slab that needs to be leveled. We took up the old carpet and pad and have plenty of yellow glue left on the cement. Do we really need to remove the glue and what is the best way? Or is there a leveling compound out there that can be applied over the old glue? What is the best way to address this problem?

It is reasonable that the glue is not a asbestos based glue it being yellow and if it is not extremely sticky , I would take a 3" or 4" wide razor scraper and knock off any high spots and lay the floating pad right over and install the floating floor over it.

There is no need to do anything except as jwmaximus says knock off the high spots. Don't forget to use a moisture barrier along with the pad.

Yes, leveling compounds require that substrate is to be clean and free of sealers, paint and other comtaniments that would interfer with the bonding of the compound to the substrate. Self leveling compounds require a primer as well.

Scrape the adhesive off and try and find someone with a scarifier or dustless grinding system.

Thanks for the help. The glue can't just be scraped, it is so hard we could barely put a dent in it with a chisel and hammer, that's the old one. The newer one is "only" around the perimeter and is sticky. So we rented a floor polishing machine with a carbide grinding attachment to get at least the leftover pad and sticky glue off. Then we primed and poured a whole lot of self leveling compound on it...$$$. I never mentioned that our leveling means spots up to 3/4 inches difference. We found out that this room used to be a 3 season porch! Nice project to start with in our new house. So right now we're still trying to get rid off a high spot, about 2 by 4 feet hump, that we need to grind down somehow?

This is a good deal. Hook it up to a 4 inch grinder and a shop vac.

http://www.google.com/products/catalog? ... ps-sellers

Their website: http://www.dustlesstechnologies.com/dustbuddie.htm

The dustbuddie is the more expensive one.

That looks like a good tool, thanks.
I have another problem now: after letting the self leveling compound dry for a few days, small cracks appeared on the surface! I'm not happy about that at all to say the least. I suppose this is not normal?

Yes, quite normal if your going that deep sometimes. Adding some aggregate (pea gravel) helps keep it from cracking. I wouldn't worry about it even if I was gluing.

Thanks so much for your positive answer, made me a whole bunch calmer! Happy new year!