# Major dusting from new concrete floor



## MoreCowbell (Dec 30, 2014)

Hello. As I described in an earlier post (http://www.houserepairtalk.com/f39/n...project-11441/) I've been working on converting my crawlspace to a basement.  I am just about done.  I just need to work on the staircase framing reinforcement a bit and add a handrail.

However, my big issue now is that most of the slab sections I poured (I did it DIY in sections) are having a pretty serious dusting issue.  Just running a broom across the surface or rubbing your foot will cause cement dust to rub off.

During each pour I tried not to mix the concrete too wet, and waited as long as I could to float and trowel it, but each section kept dusting afterwards.  I think pouring the concrete directly on a vapor barrier was a big part of the cause.  The bleed water was never ending it seemed.

Anyway, that is water under the bridge now.  I'd like to do what I can to resolve it.  Here are several options I can think of:

1) Use a concrete densifier?  This seems to be the simplest option, but I already tried the "_X-1 Silicate based Densifier and Hardener_" product from Stone Technologies with a few sections but it did not really do anything.  Are the lithium or potassium based products better than silicate?

2) Grind the weak top layer off?  I'm thinking that either a rented walk-behind diamond grinder or a diamond cup on my angle grinder would work.  I have 600 SqFt of floor to do, so is the angle grinder out of the question?  The extra work of the grinding option doesn't bother me too much as it would allow me to fix some ugly finishing work on a couple of the slab sections.​
Any thoughts from the pros?  Thanks for your help!


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## nealtw (Dec 30, 2014)

I found this over at This Old House.
http://www.thisoldhouse.com/toh/asktoh/question/0,,449666,00.html


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## MoreCowbell (Dec 30, 2014)

Thanks nealtw.  It seems like the acrylic sealer route would be pretty easy to do.  While I am shooting for more of a permanent solution, and this sounds like more of a temporary thing which needs to be reapplied periodically, I suppose it would not hurt to try it to see how it goes.


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## nealtw (Dec 30, 2014)

acrylic  concrete sealer is what they use on driveways and patios. In the basement I would expect 10 to 15 years.


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## stadry (Jan 2, 2015)

w/all due respect, we'd pick a concrete densifier instead as it hardens conc


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