Crack/Gap filling for epoxy prep

[mjenk430]

I pulled the trigger on the armorclad epoxy today. Have some prep questions:

I have small cracks/expansion joints I want to fill. Also some gaps between concrete walls and edge of slab. Can I use rust oleum epoxy shield concrete patch and repair and then grind smooth with rest of floor when I use the diamabrush? Or is there another product I should be using to fill cracks/gaps?

 

[mjenk430]

Also, I have a low area, about 3'x3' where I have already hand grinder some footprints that were in the slab. It is maybe 1/8" to 3/16" low in the middle. It isn't that noticeable when walking across it. Should I just leave it alone or level it out with some sort of self-leveler? If I fix it what should I use?

 

[73RR]

What does armorclad say about bridging cracks?
For the low spot, does the product allow for build-up? If so, just fill the area with a little extra assuming it will self-level.

 

[Shea]

The gaps between the concrete slab and walls is an expansion joint. You do not want to fill that with a hard filler an coat over it. It will crack. Fill those joints after you coat the floor. You will want to use a flexible self-leveling polyurethane sealant such as SikaFlex. It may require stuffing some backing rod down into the joint first.

Your cracks can be chased and filled with the Rust-Oleum crack repair material. The Diamabrush will grind it flush if you do not over fill too much. Otherwise, a turbo cup grinding wheel on a small grinder works well for grinding repairs flush.

If you want to fill your contraction joints, give ArmorPoxy a call and ask them what they have for that. Most vendors carry an epoxy gel filling product that has a higher elongation rate to avoid cracking when filling contraction joints. If they don't carry it, I know the other vendors here do.

 

[mjenk430]

Thank you Shea for the detailed response. (Your website has been very helpful as I have been wasting hours upon hours reading about epoxy floors the last couple of weeks!)

Do you have any advice regarding the low spot I created by grinding down footprints in the slab using a 4" grinder and diamond cup wheel? It is not very noticeable when I walk across it but when I span it with a 4' level it is about 1/8" to 3/16" low in the middle. My concern is when I put an epoxy coating on it, it will stick out like a sore thumb. Am I best off leaving it alone or should I try to fill with some sort of self-leveling product?

 

[tlmartin84]

With the self leveling, you could paint that area first with the epoxy, then grind over it. Then a apply your full layer over it. I don't think I would try any levelers.

With the self leveling epoxies they will fill some of the shallow dents on their own.

 

[tlmartin84]

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My floor was all kinds of outta whack. Still is. But you can't see it. The epoxy filled most of the shallow spots, and what wasn't filled is so camouflaged you can't tell.

 

[mjenk430]

With the self leveling, you could paint that area first with the epoxy, then grind over it. Then a apply your full layer over it. I don't think I would try any levelers.

With the self leveling epoxies they will fill some of the shallow dents on their own.

That's an idea! I will have extra epoxy because I was forced to buy 900SF (600 + 300) to do a 700SF area.

Why would I need to grind the epoxy in that area? Won't it stick to itself?

 

[mjenk430]

My floor was all kinds of outta whack. Still is. But you can't see it. The epoxy filled most of the shallow spots, and what wasn't filled is so camouflaged you can't tell.

That floor looks great! I don't see the imperfections. Maybe I'll just do nothing...

 

[tlmartin84]

That's an idea! I will have extra epoxy because I was forced to buy 900SF (600 + 300) to do a 700SF area.

Why would I need to grind the epoxy in that area? Won't it stick to itself?

Not once it sets up. There is typically a recoat window on epoxies for the chemical bond, you would have to check with the manufacturer. Once it goes to the full cure, You will have to grind it to get a mechanical bond.

I am almost embarrassed to show this but......... that is the before and after. The drain is the same, use it for location....

I am an engineer, not a concrete guy. We build bridges, which end up floated, and broom finished. I do well with sidewalks on my own, so I thought I'd give finishing the floor a try. Long story short, it was 34x44 and it got away from me.

I didn't care too much though because I knew I was going to epoxy it. I am grinding out the divits, filling them and moving on. To me it a shop. The money I saved paying someone to do it, was well worth it to me.

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[tlmartin84]

Oh.....and I just want to also state, the concrete supplier played a hand in the crappy finish.

I had used screed key, and had it set up for 3-8 yard trucks. 3 - 34x15 pours. Well they sent 8 on the first, and 6 on the next load. It messed up the time I had setup between pours to finish each section, because emptying the truck put me in the middle of another slab.......

 

[mjenk430]

Oh.....and I just want to also state, the concrete supplier played a hand in the crappy finish.

I had used screed key, and had it set up for 3-8 yard trucks. 3 - 34x15 pours. Well they sent 8 on the first, and 6 on the next load. It messed up the time I had setup between pours to finish each section, because emptying the truck put me in the middle of another slab.......

You have bigger balls then me. I am DIY on most things but I would never have the nerve to pour a slab that large. I have the philosophy: Give me enough time to think something through and work on it and I can get it done. It might take me 4 times as long as a professional but I like learning the process. I don't do well with projects that are time sensitive and rushed. That's why the epoxy worries me. Once it's mixed, it's GO TIME! Trying to get all my ducks in a row well before hand.

Glad your project turned out nice in the end, looks like epoxy will cover-up a lot of sins.

 

[Armorpoxy]

Flecks really disguise floor irregularities and such. A full gloss floor will show everything.