Oh, the dust. New concrete blues...

[FEF]

All,

I'm so confused....

I have a new shop with a floor that was poured about 3 months ago. It's dusting like crazy. Every time I sweep, there's a bigger pile then the time before. Will this end some at some point?

On a related note, I'm still confused about the best flooring. I had an epoxy covering in my last garage. It looked GREAT untill the first bit of metal shavings hit the floor. Over time, it came off becasue the shavings and slag would get ground in by walking in the work area. It can't survive there.

I'm thinking that what they do at warehouses might be best for me. Though, I'm not sure what they do. Do they just polish the concrete?

We don't talk about concrete polishing, much. What's involved with that? Do I really want to consider such a thing?

 

[Dave Carney]

Were the temps cold after the pour? Shouldn't dust like that, at least mine didn't.

 

[FEF]

Were the temps cold after the pour? Shouldn't dust like that, at least mine didn't.

It was cold, but not freezing. Now, it froze about 1 week after, though.

It's pretty dusty, for sure.

 

[bmwpower]

It was cold, but not freezing. Now, it froze about 1 week after, though.

It's pretty dusty, for sure.

That may have something to do with it if it was wet on top. Did they add calcium to the mix?

Did you try washing it away?

 

[boiler7904]

All,

I'm so confused....

I have a new shop with a floor that was poured about 3 months ago. It's dusting like crazy. Every time I sweep, there's a bigger pile then the time before. Will this end some at some point?

On a related note, I'm still confused about the best flooring. I had an epoxy covering in my last garage. It looked GREAT untill the first bit of metal shavings hit the floor. Over time, it came off becasue the shavings and slag would get ground in by walking in the work area. It can't survive there.

I'm thinking that what they do at warehouses might be best for me. Though, I'm not sure what they do. Do they just polish the concrete?

We don't talk about concrete polishing, much. What's involved with that? Do I really want to consider such a thing?

Dusting is a normal attribute of newly placed concrete. My first question would be if the concrete had a clear liquid sealer / dustproofer / curing compound applied shortly after placement. If not, that would explain the dusting.

Don't do anything to the slab until you figure out what you are doing with the finish. Many epoxies require that sealers be removed from concrete so that they can penetrate the surface and bond to the slab. Applying a sealer now may just require removing it later depending on the finish. You end up paying twice to get where you are now.

 

[Hammerdown]

Sounds like a calcium chloride add mix was used due to the cold weather and now the floor has efflorescence. These salt crystals from the add mix (and naturally occuring to a lesser degree in the concrete mix) are depositing on the surface through excess moisture, causing the surface to powder. This can indicate that the entire surface could become powdery and deteriate so it will be unable to successfully bond with and hold a coating. Take the edge of a key or screwdriver and rub it in various spots over the floor. If the concrete flakes away or a lot of dut is created, you should grind the floor to remove this unstable surface. Rent an EDCO grinder, upgrade to the diamond tips and grind the surface until you reach a "hard" layer. With an EDCO you can remove as little as 1/32 at a time, so make a couple passes to acheive the desired result. Once the soft surface has been ground away, you should be able to apply a coating with a very good chance of success.

 

[MXtras]

Wow. Nice info.

Thanks!

Scott

 

[FEF]

Indeed. Very good info.

Looks like grinding is in my future.

 

[cyco]

Rent an EDCO grinder, upgrade to the diamond tips and grind the surface until you reach a "hard" layer. With an EDCO you can remove as little as 1/32 at a time, so make a couple passes to acheive the desired result. Once the soft surface has been ground away, you should be able to apply a coating with a very good chance of success.

To back this up, this is the same advice UCoat-It gave me when I asked about my 1.5 year old dusty floor.