# Diamond grinding concrete



## Tonyg (Dec 9, 2007)

I am putting in a bid for a hotel that has 3,000sf of sidewalk (broomed) and a few hundred sf of smooth steps. 2,200sf has about 15 mil of alkyd. Looking at grinding up the old coating as well as the existing uncoated crete. The steps will need to be hit by hand. Will be putting down SW SherCrete with a couple of coats of H&C clear.

This is something new to me and I think have padded in ample time for the grinding but I am a little concerned with what kind of production times I should have assigned for it. I will be renting the grinders and vac.

Any suggestions or tips for what to look out for in the grinding? Any ideas on production time for grinding?


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## NACE (May 16, 2008)

If I were using a 16" On Floor grinding machine with carbide scarifying blades, I would estimate that broomed concrete with 15 mils of alkyd paint, tight adhering would take 4-8 hours down to a clean, bare surface. The stairs may prove challenging since this is being done by hand, the concrete is smooth, and not sure if you require a profile on the concrete in the spec, or what the profile is to accept a coating. I have completed 5500 sq ft of failing polyamide epoxy on broomed concrete in 6 hours, but every floor and concrete hardness are different. Is the current system failing?


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## Tonyg (Dec 9, 2007)

NACE said:


> If I were using a 16" On Floor grinding machine with carbide scarifying blades, I would estimate that broomed concrete with 15 mils of alkyd paint, tight adhering would take 4-8 hours down to a clean, bare surface. The stairs may prove challenging since this is being done by hand, the concrete is smooth, and not sure if you require a profile on the concrete in the spec, or what the profile is to accept a coating. I have completed 5500 sq ft of failing polyamide epoxy on broomed concrete in 6 hours, but every floor and concrete hardness are different. Is the current system failing?


 
Its only failing on the steps. About 2k is coated and is tight but has a gloss and somewhat slippery. The hotel has had several slip and fall but I would assume mainly on the steps which are probably a hundred feet long. I opted for the diamond grinder and would either use a 10" or one with two disks so I am assuming 18-22".

It sounds like I put enough time on the broomed crete but not sure about the steps. I am also concerned with chipping or gouging the smooth steps. Using a cup disk on a hand held, are they easy to cut too deep or will it pretty much only eat the cream.


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## YubaPaintPro (Mar 2, 2008)

Tonyg,
sorry I am late to the dance here, but know this, NACE is way more qualified than I. That being said, is this exterior? If so, you're color will very likely fade out of the coating even w/ the clear topcoat. IF the TDS shows adhesion to "aged oils" then apply w/o the grind, to avoid any asthetic issues you may create.

Good luck. Check out these products, they may have something for the steps.
http://www.paintshaver.com/index.html


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