Newbie Here: Grinder, Shot Blast or ......?

[Soundchasr]

Hi all:

I'm planning on putting down an epoxy floor in my garage. The house is about 15 years old. You can see in the pictures the condition of the floor. It's mostly covered in joint compound and dust right now. I can't tell if it's ever been sealed.

I want to make sure I do the prep right so I was thinking of shot blast or diamond grinder but I've never used either. Which would be better for the flooring newbie? Also, how concerned should I be about Pittsburgh winters effecting the floor?

Thank you!

 

[Soundchasr]

Anybody? Any suggestions on the type of contractor to call if I don't do it myself?

 

[jmh21586]

How big is the floor??
It looks like it is sealed.

 

[Soundchasr]

How big is the floor??
It looks like it is sealed.

It's 21.5 x 21.3. So, about 450 feet. It looks like it's sealed to me too. I'll check for sure tomorrow.

 

[krooser]

I sand it with an orbital sander, wash it and coat it. Did that with mine...

 

[Soundchasr]

I sand it with an orbital sander, wash it and coat it. Did that with mine...

What did you use on your orbital?

 

[Jaguar Fan]

I'm going to suggest something different. I'm not a pro - but this is what I would do if it were my floor.

First, I would thoroughly power wash the floor to remove the joint compound, drops of paint, etc. Get it nice & clean of surface ****.

Then I would aggressively clean it. A strong degreaser & a stiff brush on the end of a long handle. Spend quite a bit of time cleaning it. Then powerwash, powerwash, powerwash to get all of the detergent off it.

Let it dry for a couple days, then do the "drop test" -- a few drops of water in a few locations around the garage to see if it "beads" (sealer) or soaks in (no sealer).

Assuming it is unsealed, I would let it dry for at least a week.

Then I would do the moisture test - get a 3 foot by 3 foot heavy piece of sheet plastic, and duct tape it to the floor, sealing all edges. Let it sit for at least 24 hours. Pull it up & see if underneath the plastic is dry or damp. If it is damp, your concrete may not have a vapor barrier underneath & hence might not take an epoxy.

If the garage floor is sealed, then its time to get a grinder to grind it off, and then do the moisture barrier test. If it passes, then I'm good to go with epoxy.

If the garage was not sealed, and if it passes the moisture barrier test, then I can grind or acid etch or shot blast. The physical condition of the concrete would probably determine which I'd do. The pros usually grind, so that is the direction I'd lean. I couldn't rent a grinder when I did a 2 car garage in Las Vegas, so I acid etched & it seems to be holding up fine.

Let us know how the project goes!

 

[Randar68]

Or you could skip about half of what JaguarFan said and just shotblast it and be done with it. Problem for some people is they can't find a shotblaster they can rent locally. There are a few threads around here you can search for on details of national rental places that carry them. You'll have to call around.

If you're going to do it, just scrape the plaster globs off, and use a degreaser on any greasy areas. Then shotblast that mutha and powerwash. Let dry and you're ready to go. You don't want a smooth surface to lay the epoxy down. You want more surface area to bind to, which means it should be semi-rough and IMO shotblasting will give you best profile and greatest likelihood of success.

I chose Wolverine products, although my floor hasn't gone through a whole winter yet (crazy Chicago salt usage be damned)... If it holds up in my garage, it will hold up anywhere.

 

[Soundchasr]

Or you could skip about half of what JaguarFan said and just shotblast it and be done with it. Problem for some people is they can't find a shotblaster they can rent locally. There are a few threads around here you can search for on details of national rental places that carry them. You'll have to call around.

If you're going to do it, just scrape the plaster globs off, and use a degreaser on any greasy areas. Then shotblast that mutha and powerwash. Let dry and you're ready to go. You don't want a smooth surface to lay the epoxy down. You want more surface area to bind to, which means it should be semi-rough and IMO shotblasting will give you best profile and greatest likelihood of success.

I chose Wolverine products, although my floor hasn't gone through a whole winter yet (crazy Chicago salt usage be damned)... If it holds up in my garage, it will hold up anywhere.

I searched around my area but couldn't find a shot blast. I found a hand orbital with vacuum at HD that I'll probably rent.

Do I need to worry about getting paint and joint compound off first if I'm using the grinder? Any additional prep after grinding?

I'm thinking about epoxy-coat but will also look at Wolverine.

 

[Randar68]

I searched around my area but couldn't find a shot blast. I found a hand orbital with vacuum at HD that I'll probably rent.

Do I need to worry about getting paint and joint compound off first if I'm using the grinder? Any additional prep after grinding?

I'm thinking about epoxy-coat but will also look at Wolverine.

You'll probably want to try to scrape up what you can with a scraper, but it won't matter much if you're going to roughen everything up with a diamand grinder.

Remember, you want it to be rough, not smooth.