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Concrete Surface Texture
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04-12-2011, 10:48 AM #1
eaadams Concrete Moisture Expert *****
Status: Offline Posts:587 Threads:83 Joined:Jul 2010
Does anyone know how to 'say' different levels of concrete grinding?

On a job & the concrete grinder says what we are looking to achieve is a "40 grit".

I don't think a std CSP profile of 1-2 is precise enough.

Looking to build it into our spec.

Anyone help? Idea is a concrete smoothness to receive sheet vinyl.

04-12-2011, 01:11 PM #2
Ernesto Concrete Moisture Expert *****
Status: Offline Posts:606 Threads:33 Joined:Sep 2009
If you cannot find it in here, then you can't find it anywhere. Might take some searching. Smile

http://floorexpert.com/

Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com

04-12-2011, 01:54 PM #3
CC Solutions Concrete Moisture Evangelist *******
Status: Offline Posts:1,065 Threads:69 Joined:Dec 2009
The ICRI standard CSP chart is well known and I can't find any reason to add more precision to the chart. Actually a CSP 2 or 3 are very close already. I would say a CSP 3 closely resembles 40 grit sandpaper.
That said, grinding and achieving a 40 grit surface or CSP 3 will not be easy. Grinders leave a surface quite smooth and the dust created by grinding fills in voids making the surface even smoother.

JD Grafton
Concrete Answers for Flooring Problems
JGrafton@ccsolves.com

04-12-2011, 01:56 PM #4
eaadams Concrete Moisture Expert *****
Status: Offline Posts:587 Threads:83 Joined:Jul 2010
So it is refering to sandpaper? ok.

I had found some 40 grit diamond wheels but that doesn't refer to the finished surface.

http://www.perkinscustomcoatings.com/docs/Concrete_Prep%20Guide.pdf

04-12-2011, 02:13 PM #5
CC Solutions Concrete Moisture Evangelist *******
Status: Offline Posts:1,065 Threads:69 Joined:Dec 2009
Yes, we use 20 - 30 grit diamonds and it is much smoother than a light brush blast.

JD Grafton
Concrete Answers for Flooring Problems
JGrafton@ccsolves.com

04-12-2011, 08:23 PM #6
Ernesto Concrete Moisture Expert *****
Status: Offline Posts:606 Threads:33 Joined:Sep 2009
Is that the rule for resilient? I thought the manufacturers set the rules? Where's Ray? He would know this off the top of his head.

Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com

04-12-2011, 09:10 PM #7
CC Solutions Concrete Moisture Evangelist *******
Status: Offline Posts:1,065 Threads:69 Joined:Dec 2009
The rule for resilient? Resilient follows ASTM F710. Clean dry absorbent with no contaminants. You do not have to profile the floor before installing resilient. Resilient manufacturers also specify the flatness of a floor, but I think they still use the old 1/8" in 10 feet rule which doesn't mean much.

Vinyl floors will benefit from a good Ff number on the concrete. A grinder can help achieve good Ff numbers whereas a shot blaster cannot.

I don't understand the confusion here I guess. The concrete grinder guy on your job may be looking for a 40 grit finish. He'll try to grind the floor as rough as he can then. As for a spec for you to build into your specs, you want a floor smooth. You don't want grinder marks, swirls, pits, and you also don't want concrete undulations or waviness.

So for a surface profile to install resilient flooring, you want a CSP 1 or 2, maybe a 3 will work but you don't want any overlap marks or gouges to deal with.

For concrete flatness, you want the best number you can get. And you will not be as concerned with the levelness of the floor which is expressed as Fl, your concern will be the Ff number or the flatness of the floor.

Fl is a number generated by measuring points along the floor and determining a maximum variation. So a floor can dip 1/2" per ten feet, or it could dip 1/2" every foot and still meet the same Fl number.

The Ff number is a flatness number that takes frequency in account. To achieve a high Ff number you can't have big dips or bumps, or many of them. And we all know a resilient floor looks better if the substrate is smooth and flat under it!

Here's a good site I just Googled up that has some quick-read Ff explanations... http://www.faceco.com/40q.html

You know the weird thing is I just gave a lunch-n-learn tonight and was discussing Fl Ff numbers with an engineer over a beer afterwards.... Weird!!! Cool

JD Grafton
Concrete Answers for Flooring Problems
JGrafton@ccsolves.com

04-12-2011, 10:28 PM #8
eaadams Concrete Moisture Expert *****
Status: Offline Posts:587 Threads:83 Joined:Jul 2010
yes I understand all of that.

Ff/Fl is not the point, nor is 1/8" in 10'.

I'm dealing with a situation where the idiot GC called in the concrete sub to grind the slab, the sub scarified and then filled w/o any attention to trowel work and smoothness. If we laid to their fill it would be a lumpy mess.

So now we have to change order them to grind the mess on the joints down flat and smooth.

I hate this fight. Always at the end of a job, always a GC not being diligent, always vs bad low bid concrete companies.

04-13-2011, 06:03 AM #9
CC Solutions Concrete Moisture Evangelist *******
Status: Offline Posts:1,065 Threads:69 Joined:Dec 2009
Technically I think Ff is the standard you can use to enforce what you need.

Why do subs do this? Are they upset they have to come back? Are they unaware that the waves will show through the floor? I always try to get with the actual guys doing the grinding right when they start and show them exactly what I need. If they have a problem with my demands, they can complain up the ladder (which they usually do). That will prompt an immediate meeting of all parties and a good discussion can take place regarding what is an acceptable floor to lay resilient on and who is responsible to get it to that condition.

You are right, we should have Ray chime in here.... He wrote the book on resilient flooring.... literally Big Grin
I sent Ray a PM. Cool

JD Grafton
Concrete Answers for Flooring Problems
JGrafton@ccsolves.com

05-19-2011, 11:49 AM #10
rthompson Industry Expert *****
Status: Offline Posts:72 Threads:0 Joined:Sep 2008
The CSP necessary, is determined by the concrete and what, if anything is on it. A concrete that has either a sealer or curing compound on needs to have the CSP agressive enough to open the pores in the slab.
A slab that has an adhesive, especially cutback needs an even more agressive CSP 3 or 4.
Take care
Rayt








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