Grind and level or just epoxy?

[JAD75]

I've been searching and have read several posts on this site. So many conflicting opinions. A little background: Around 18 months ago, we had a shop built. The concrete was poured late in the day and the guy who built the shop was trying to get it done before he end of the day. The power trowel he rented was defective; the rental place acknowledged that the next day. The rental place gave him a grinder and he went through two sets of teeth (according to him) grinding my concrete smoother. Despite the pictures below, it's actually smoother than before he ground it.
My only problem with the pad is the dusting. I have to use a shop-vac because sweeping or using the leaf-blower creates such a huge cloud of dust. The surface is smooth enough for me to do everything I need to do in the shop, but I need to fix the dusting. My wife draws disability, so we don't make a lot of money. Whatever gets done has to be done by me and must be done in stages; I can't afford to empty my shop into a storage unit and do the floor all at once. Ripping it out and repouring isn't an option and neither is calling in professionals.
I've seen solvent-based acrylic sealer recommended. I've also seen "densifier" recommended, as well as levelling compound. Just walking on it will cause small piles of dust, so I'm assuming I'll need to do a little more grinding, first. I can buy small diamond wheels for my 4" grinder and can take as much time as I need to grind, but what's the best course of action after that? Sealer? Denisfier? Levelling compound? My only goal - my ONLY goal - is to stop the dusting.

 

[kmacht]

Are you the “guy who built the shop”? If not then why isn’t he paying to have the floor epoxied?

 

[Matty J]

How soon after the pad was pour did the contractor grind it?

 

[Garage Flooring]

If this were my floor:

Grind using an Edco style grinder NOT Diamabrush
Prime with a waterbased primer
High solids intermediary coat
100% solids epoxy
flake
Clear

 

[JAD75]

Are you the “guy who built the shop”? If not then why isn’t he paying to have the floor epoxied?

He's not paying because I can't afford to make him pay.

 

[JAD75]

How soon after the pad was pour did the contractor grind it?

It was more than 24 hours. It's been a year ago, but it was two or three days after the pour. He did the pour, I saw the bad finish job the next day, he came and looked at it (possibly the day after that) and ground it the day after. So, he did the grind 2-4 days after the pour.

 

[JAD75]

If this were my floor:

Grind using an Edco style grinder NOT Diamabrush
Prime with a waterbased primer
High solids intermediary coat
100% solids epoxy
flake
Clear

So, grinding with my little 4" grinder is out of the question? I've got plenty of time to do work. Money is a different thing altogether.

 

[Matty J]

It was more than 24 hours. It's been a year ago, but it was two or three days after the pour. He did the pour, I saw the bad finish job the next day, he came and looked at it (possibly the day after that) and ground it the day after. So, he did the grind 2-4 days after the pour.

Yea that’s probably why you are having a bad dusting issue. Concrete needs a minimum of 30
Days (officially they say 28 days) before any grinding happens so the concrete didn’t cure properly. I’m sorry for your unfortunate situation!

You can grind it with your handheld grinder, it’s going to be really dusty so I would absolutely suggest installing a dust shroud onto your grinder (harbor freight Hercules brand is surprisingly good and cheap) and having it hooked up to a vacuum.

Then just vacuum the heck out of the slab and get some sort of Solvent based sealer and roll it on. Not the ideal process, but it’ll at least stop the dusting.

 

[JAD75]

Yea that’s probably why you are having a bad dusting issue. Concrete needs a minimum of 30
Days (officially they say 28 days) before any grinding happens so the concrete didn’t cure properly. I’m sorry for your unfortunate situation!

You can grind it with your handheld grinder, it’s going to be really dusty so I would absolutely suggest installing a dust shroud onto your grinder (harbor freight Hercules brand is surprisingly good and cheap) and having it hooked up to a vacuum.

Then just vacuum the heck out of the slab and get some sort of Solvent based sealer and roll it on. Not the ideal process, but it’ll at least stop the dusting.

I've got a shop vac and can buy the attachments you're talking about. Would soaking the concrete with water while I grind be an alternative? No dust; then, I can vacuum after it dries?

 

[Matty J]

I've got a shop vac and can buy the attachments you're talking about. Would soaking the concrete with water while I grind be an alternative? No dust; then, I can vacuum after it dries?

Wet grinding is an option, but it’ll make a hell of a mess and wouldn’t recommend it with a hand grinder. It’ll create a slurry which you’ll have to figure out a way to remove and dispose of. Dry grinding with a vac attached is probably a much more painless option.

 

[Garage Flooring]

So, grinding with my little 4" grinder is out of the question? I've got plenty of time to do work. Money is a different thing altogether.

You rally need to rent the proper equipment

 

[CoRestore]

So, grinding with my little 4" grinder is out of the question? I've got plenty of time to do work. Money is a different thing altogether.

You can for sure grind this by hand, but its going to be very time consuming and dusty. Make sure you get a shop vac with a hepa filter of some sort. You could also get a dust deputy from Harbor freight. I think they are around $40.00. Dust separator. Hopefully you do not have that much sq ft. Sorry to hear about the issues.

 

[Garage Flooring]

You can for sure grind this by hand, but its going to be very time consuming and dusty. Make sure you get a shop vac with a hepa filter of some sort. You could also get a dust deputy from Harbor freight. I think they are around $40.00. Dust separator. Hopefully you do not have that much sq ft. Sorry to hear about the issues.

The pour was described as a shop which would give me the impression he is dealing with significant square footage. Based on the description of the issue I think it would be less expensive and more efficient to just get the rent the right tools to start with.

OP: You could try a densifier just for the dusting. But a densifier itself will not fix bad concrete.

 

[JAD75]

You can for sure grind this by hand, but its going to be very time consuming and dusty. Make sure you get a shop vac with a hepa filter of some sort. You could also get a dust deputy from Harbor freight. I think they are around $40.00. Dust separator. Hopefully you do not have that much sq ft. Sorry to hear about the issues.

900sf. But, like I said, I'll have to do it in sections. So it's not like I'll be grinding 900sf all at once. Thanks for the advice.

 

[JAD75]

You rally need to rent the proper equipment

Easier said than done, for some of us. I won't be able to do the whole floor all at once. I'm going to have to clear one part of the floor, do all the work to that section and then clear another section. I'd be renting equipment several times just to do that. The concrete doesn't seem bad, it's just dusty. It's worse near the edges, which makes sense: he wouldn't have gotten the grinder terribly close to the edge due to the metal siding.

 

[Garage Flooring]

Easier said than done, for some of us. I won't be able to do the whole floor all at once. I'm going to have to clear one part of the floor, do all the work to that section and then clear another section. I'd be renting equipment several times just to do that. The concrete doesn't seem bad, it's just dusty. It's worse near the edges, which makes sense: he wouldn't have gotten the grinder terribly close to the edge due to the metal siding.

Does it score easily?

 

[JAD75]

Does it score easily?

I used a key to scratch the shop floor and then went and did the same thing on the concrete foundation around our house (poured years apart by different companies). The shop floor took the same amount of pressure to score it as the foundation did. So, I'd say it doesn't score easily.

 

[Armorpoxy]

Hi, the Ghostshield Densifier/Sealer combo would work great for this. Easy to apply, we carry it.

 

[BombShelter]

I use my little grinder hooked to a dust deputy going to a hepa vacuum with filter cleaning banging (Bosch VAC090AH). A little dust will clog most filters in minutes unless you have a set up like mine. The vacuum is not for large jobs but might work in your situation.

The last job I did was getting tile grout off a floor and it's really hard to keep the grinder flat. When it's not flat it's cutting into the floor and I think your project might look worse when your done.

I'm not an expert on floor coatings, would a good quality gray floor paint work? In the old days when basements were used for basements, everyone painted their basement floors gray.