Carpet that is attached to a concrete floor is usually held down by adhesive. Unfortunately, when you remove the carpeting to replace it, the adhesive usually does not come off with the carpet in all areas. Instead, what is often left behind is course sections of dried adhesive that have bonded to the concrete floor in such a way that they are very difficult to remove. Separating the adhesive from the concrete is essential in order to properly clean and prep the concrete for new flooring installation.
Use a handheld floor scraper for small jobs. Hand-held floor scrapers have sharp blades that efficiently separate the adhesive from the concrete, so that it can be easily swept away.
Sweep the concrete floor well using a broom and dust pan. Follow up with a light vacuum, using the vacuum's floor attachment. The concrete floor should be completely free of all adhesive residue, dust and dirt before applying a cleaning solution.
Fill a bucket with approximately one gallon of water and a few squirts of dish soap. Thoroughly, mop the concrete floor; wringing the mop out in between to make sure that you do not over saturate the concrete floor with water. Change the water as you go if it becomes too dirty.
Allow the concrete floor to air dry overnight before re-carpeting or performing any installation over top of it. Otherwise, you can create a mildew problem if water is trapped between the concrete and the new flooring.