Tim,
I am having a new home built in northern PA. The contractor poured the concrete floor in the basement and it looked great for a week or so. Now the floor looks all blueish and blotchy. What went wrong?
Archie
- - -
Archie,
There may or may not be anything wrong. The two things that come to mind would have been the addition of any chemical accelerators added at the jobsite to hasten the hydration of the mix. This is often done in cold weather so the finishers don't have to hang around all night waiting for the concrete to set.
The second thing may be the addition of water as they finished the slab. This is not a good idea and can lead to coloration differences. The color usually will turn a light gray or white over time. Sunlight hastens this but once the subfloor goes on, the slab will never get direct sunlight again. Just hang loose and see what happens over time. My biggest concern would be dusting - a condition where the cement paste at the surface wears off easily because of the water added to help finish the slab.
Tim Carter
www.askthebuilder.com
W3ATB