What are my options...can't take this dusty concrete any more!

patent pending · Mar 28, 2012

We bought our house two years ago and unfortunately I didnt realize how bad the garage floor was. My main concern is to be able to eliminate the dusting. After looking at the floor, the side on which my wife parks her car has been worn down to the aggregate. The other side which sees very little activity still has a layer of crumbly/sandy concrete on top. It appears solid and smooth, but I can scrub it down a quarter of an inch or less and it feels like I get to a more solid layer.

Should I be able to hit this with a grinder and knock that top layer off, clean it up good and use some densifier to take care of the dusting?

Epoxy would be great if I could do that without having to use a densifier first....not sure what that would look since the surface isn't that smooth at all.

Racedeck is not in the budget!

Thanks

The picture was taken in the same spot.

STIBuilder · Mar 28, 2012

I just picked up 5gal of Ashford Formula for under 100$ local that i plan to do seal up my floor with. Seems reasonable.

dcs Inc · Mar 28, 2012

Ashford wont correct a bad surface. It will densify a good surface. This needs to come off with a deep grind. Then densify. gene

STIBuilder · Mar 28, 2012

Yeah, use the densifier post cleaning, but you already said you were going to clean it, looks like a grind is in order. What does it look like after you sweep the floor?

regguy1 · Mar 28, 2012

Check my epoxy thread link on this page, not expensive and has held up very well: http://www.garagejournal.com/forum/showthread.php?t=140674

Edger · Mar 29, 2012

At least it will grind off easily, take it down to the aggregate and then harden. Unfortunately that will expose lots of air holes which need to be filled if you are going to coat over it.

patent pending · Mar 29, 2012

STIBuilder said:
Yeah, use the densifier post cleaning, but you already said you were going to clean it, looks like a grind is in order. What does it look like after you sweep the floor?

It looks pretty decent after a sweep...but it doesnt stay that way for very long. I think just foot traffic on it is enough to loosen up a little grit.

Edger said:
At least it will grind off easily, take it down to the aggregate and then harden. Unfortunately that will expose lots of air holes which need to be filled if you are going to coat over it.

It will definitely grind off easy! I dont know if I should grind on the side that is already worn down or not? It's not really crumbly any more, just still really dusty. What do you suggest for filling the air holes before coating?

dcs Inc said:
This needs to come off with a deep grind. Then densify. gene

Thanks...thats what I was figuring. :thumbup:

thegarageguy · Mar 29, 2012

I've seen this before from shady contractors. They did a bad pour and hide it with a cap gyp-crete. It's basically sheetrock. It looks like you may be a victim of this immoral practice.

If you can dig your car key into it and gouge it, it's gypsum. All you can do it scarify it off. densifier will do nothing but empty your wallet.

Edger · Mar 29, 2012

My opinion is that you do not have much choice, you need to grind both sides the same, densify (and hope it works) and ask Scotty from Legacy what to fill the holes with. I would lean towards an epoxy after filling the holes because the densifier will hopefully harden the concrete around the aggregate and most of the loading will be on the aggregate rather than the concrete after grinding. The epoxy will soak into the surface around the aggregate and with some luck it will hold well and give you a durable surface.
Trouble is it is unclear whether the problem is just the surface which I doubt, or right through the slab and densifiers can make a big difference to good concrete, but the difference they make to soft concrete is not as noticeable. My guess would be that they added water to make the mix easier to place and that water just weakens the concrete.
If you can grind it to the aggregate and coat it the floor should be OK for your light application.
By the way, when you grind, the dust will be immense because of the softness so you will need a really good vacuum and stop and start a few times to clean up and empty the vacuum and clean the filters.

patent pending · Mar 29, 2012

thegarageguy said:
I've seen this before from shady contractors. They did a bad pour and hide it with a cap gyp-crete. It's basically sheetrock. It looks like you may be a victim of this immoral practice.

If you can dig your car key into it and gouge it, it's gypsum. All you can do it scarify it off. densifier will do nothing but empty your wallet.

That sounds about right...would love to find out who the contractor was that poured it...

If the densifier will kill the dustyness and keep a majority of the concrete from coming loose I would probably be happy with it. There will never be a lift in this concrete or any heavy duty activities going on. I just moved my wifes treadmill out and I'd like to make a place where I can piddle with my cars, she can work out, and we aren't tracking white dust back in all over the house when we are done! :eyecrazy:

Edger said:
My opinion is that you do not have much choice, you need to grind both sides the same, densify (and hope it works) and ask Scotty from Legacy what to fill the holes with. I would lean towards an epoxy after filling the holes because the densifier will hopefully harden the concrete around the aggregate and most of the loading will be on the aggregate rather than the concrete after grinding. The epoxy will soak into the surface around the aggregate and with some luck it will hold well and give you a durable surface.
Trouble is it is unclear whether the problem is just the surface which I doubt, or right through the slab and densifiers can make a big difference to good concrete, but the difference they make to soft concrete is not as noticeable. My guess would be that they added water to make the mix easier to place and that water just weakens the concrete.
If you can grind it to the aggregate and coat it the floor should be OK for your light application.
By the way, when you grind, the dust will be immense because of the softness so you will need a really good vacuum and stop and start a few times to clean up and empty the vacuum and clean the filters.

I'm going to try and get some local help on my situtation, before I go spend the $$ on a grinder and chemicals..but that is the ultimate plan if I find its gonna be worthwhile. I cannot imagine how insane the dust from grinding is gonna be!

Thanks for all your help guys!

LegacyIndustrial · Mar 29, 2012

Everyone responded well. Grind off that cap and densify well. If the crete beneath is solid this will serve you well.

patent pending · Mar 29, 2012

LegacyIndustrial said:
Everyone responded well. Grind off that cap and densify well. If the crete beneath is solid this will serve you well.

Thanks Legacy

....Any way to figure out if the concrete below is junk or worth densifying?

LegacyIndustrial · Mar 29, 2012

Well, I only viewed your pics just now, on the road visiting a customer in Florida. You will need to grind off that cap to see what is up. If it's as weak as it looks, you will know when you hit the good stuff.

Shocker · Mar 29, 2012

+1 on the grind. I would also look at a skim coat of good fresh concrete.

patent pending · May 1, 2012

So I won a full garage kit from Epoxy Coat in their springtime contest, and I'm trying to figure out what I need to do to prep my floor. I know this junk stuff on top needs to come off. Was thinking of getting a 7" diamond cup and using the handheld grinder... since the majority of my floor is already worn down to the aggregate I dont think it would be worth it to rent one of the big machines.

After the top layer is off clean the floor and prep with the provided solution per Epoxy Coats instructions? I'm guessing my concrete isn't as hard as the floors most folks are grinding so maybe the acid will be plenty enough to prepare it? :dunno:

Edger · May 2, 2012

I think you should rent a grinder. The reason is that a 7" will be very aggressive and you can walk fast with the rental machine.

Do not acid etch after grinding, thoroughly vacuum up dust and give it a good rinse off. Coat when dry.

patent pending · May 2, 2012

thanks Edger! as far as the grinder goes...do you think is should use diamond inserts or will the regular blocks be sufficient for me?

munkey · May 2, 2012

I can't comment on the correct inserts to use, but to reiterate a previous comment: be EXTREMELY prepared to deal with the dust component. It is going to be your primary adversary on the grinding portion of this project, so make sure whatever solution you choose has a dust collection component. (A handheld grinder with a diamond wheel would probably be a viable option only if you have some sort of fancy dust shroud/hookup for it.)

My guess is that you're going to be roughly 0.5 seconds into the grinding process when you discover whether your dust control is adequate.

larry_g · May 2, 2012

Just question? If the floor was screwed up to start with and capped to look perty I think one would want to take a core sample to check that there was more than a couple of inches depth there and that the floor was worth the effort to finish.

lg
no neat sig line

Edger · May 2, 2012

Diamond inserts work very well, I do not like the blocks, they are very slow. It is true that your dust issue will be apparent about 0.5 seconds into the job. You must use the best dust collector you can, seal off the doors, wear a good mask.

A contractor has no worries because his equipment is adequate, but make sure you hire a dust collector and empty it frequently and clean the filters frequently. It will be much harder to control the dust with a 7" grinder than with a stand behind grinder.

madstat · Jun 21, 2012

I was wondering how this project went and did the grinding/epoxy do the job?

patent pending · Jan 31, 2014

madstat said:
I was wondering how this project went and did the grinding/epoxy do the job?

Sorry to be digging up an old thread...I somehow missed your question. But this is a good time for a 1+ year update. The grinding and epoxy did cure my dusty floor. :thumbup:

Ended up using my Milwaukee 7" grinder with a griding wheel (no diamond cup or anything) to knock off all the loose/weak top coat. Cleaned that up and did an acid etch as well. Layed down the epoxy and my floor was really thirsty cause it just sucked it up. I didnt get they typical smooth, glassy top coat that most people get with epoxy and a few spots are thin. But the floor is rock hard now and I have zero dust problems. I'm very pleased with the results. Not sure if the acid etch was overkill and opened the floor up too much and thats why it sucked it up?

LegacyIndustrial · Feb 2, 2014

Did you use a primer? A primer allows for the first coat to get sucked in, leaving a nice even topcoat.

patent pending · Feb 3, 2014

LegacyIndustrial said:
Did you use a primer? A primer allows for the first coat to get sucked in, leaving a nice even topcoat.

I did not use a primer..that makes a ton of sense though. Didnt even cross my mind, and I don't remember reading anything about it in the instructions that came with the kit.

I'm still happy with my textured floor though, it has a nice grip to it even when wet.

What are my options...can't take this dusty concrete any more!

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