Slab Preparation Advice

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Dec 20, 2011
Hi Folks,

After putting in laminate upstairs in my new home I decided to tackle floating bamboo over a slab on my main level. Removing the old carpet revealed an area of the slab that obviously needs attention. (see attached pics.)

This is a rough, raised area gradually rising to nearly a half inch over the floor around it. There is also a nearby crack that I suspect is a related to this thing. Finally, there are two small holes within the area.

The whole thing is less than a foot square and looks like an aborted water connection or something of the like.

Does this look familiar to anyone? Should I treat this as one would any raised area and grind away or should I treat it differently. Maybe fill the holes before I start grinding?

Any advice would be greatly appreciated!

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Grind it down with one of these kinda tools. You may strike copper and then you may not. Check the flatness with a 6ft level, keep grinding until flat. You might be able to rent one with a dust cover and hook it to a shop vac with a hepa filter.

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Sweet. I was hoping it would be pretty straight foward.

Can I grind wet to keep down dust?

Thanks for the pics and advice Ernesto.
I wouldn't do wet, maybe dampened. It will clog your filter faster. I upgraded to this vac recently.

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Rite. Looks like the vaccuum attachment is the way to go. Nice floor by the way...
Yes, thanks. Quickstep made that. That vac utilizes 2 filters and one prefilter. The prefilter bag can hold 40lbs of dust and keeps you from constantly cleaning your filters. Well worth the 8 Ducats a piece.

I demo'd ceramic tile around this island, all the thinset stuck. Only took me an hour to get'r flat.

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Glad I'm not dealing with thinset.

Should I consider a skim-coat after grind or is that inviting trouble?
Glad I'm not dealing with thinset.

Should I consider a skim-coat after grind or is that inviting trouble?

Skim coating is fine if your using an approved product like Ardex feather finish. Besides, your not adhering anything to the slab anyway. But check the underlayment manufacturers installation requirements for moisture testing.
No matter what kind of finished flooring you plan to install, the substrate must be properly prepared. In the case of a*concrete*slab, it should be solid, smooth, and level.

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