Epoxy prep questions - Crack filling?

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I am wondering about whether or not I should go about filling some hairline cracks in my garage floor (maybe 1yr old). There is a long control crack down the centre as pictured below. Will the epoxy itself fill & level this or would I risk losing too much material?

My stem walls are fairly high, rough, so I believe I will not use epoxy on those and concentrate on the floor since my Epoxy Master kit will only do 400-480sqft.

Also, a few inch section of my slab will be exposed to the elements outside the garage door it appears. I understand epoxy will yellow in the sun? I plan on doing a Heavy (not full) broadcast of paint chips, so I trust this may mask/hide an undesirable change in hue of the base epoxy due to UV exposure. Any reccommendations there ?

 

[Edger]

The hairline crack should be limited in depth so the epoxy will fill some of it, but with a single coat you will still see the crack profile a bit.

Some of the suppliers will probably add something, they could provide a thin epoxy to fill the crack, but see what they say.

 

[LegacyIndustrial]

Crack: I would drive (steel or margin trowel) a thick epoxy crack filler into it and razor scrape the surface prior to a full cure.

Exterior issue: Put your garage door down, strike a line where it hits the floor on the inside. This is where you can stop the work so it won't get funny outside. If you want a really tight end point, score the floor with a diamond or carborundum blade.

 

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Thanks guys. I have purchased some EpoxyShield Concrete Patch from Home Depot for the hairline cracks.

I was calling around regarding rentals. One local company I talked to was surprised that diamond grinding was reccommended for prepping for epoxy. They said it would polish/smooth the garage floor?

They recommended a 15" floor sander instead?

Without any previous coatings on the floor (floor is in a new home construction ~ 1 year old now) would using a 7" handheld grinder take very long? I was planning on renting this to smooth out the patching & potentially the stem walls anyways? Grinder was cheap to rent, though their diamond cup wheel must be PURCHASED for $150!

 

[stang1]

I bought a rigid 7" handheld grinder to do my epoxy coat floor last week. It took entirely too long with that grinder. Ended up renting blastrac saw tec 10" electric grinder with diamond blade and vac. Too much dust without vac. 3 car garage took 4hrs. worth it for me. Epoxy coat came out well and will post pictures on Thurs.

 

[Edger]

Thanks guys. I have purchased some EpoxyShield Concrete Patch from Home Depot for the hairline cracks.

I was calling around regarding rentals. One local company I talked to was surprised that diamond grinding was reccommended for prepping for epoxy. They said it would polish/smooth the garage floor?

They recommended a 15" floor sander instead?

Without any previous coatings on the floor (floor is in a new home construction ~ 1 year old now) would using a 7" handheld grinder take very long? I was planning on renting this to smooth out the patching & potentially the stem walls anyways? Grinder was cheap to rent, though their diamond cup wheel must be PURCHASED for $150!

That rental guy is full of you-know-what.

 

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Thanks guys. The drum sander they have has a 15" diamond pad for grinding as well. Is this a decent option as opposed to the walk behinds? My concern would be dust collection.

How can I use that without it turning into a dust storm? Dampen conrete before-hand, and then vaccuum after each small section to get rid of ground-off conrete?

 

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So I have finished grinding. Rented the 7" handheld grinder. Took the greater part of the day with myself & my father-in-law trading shifts.

Have swept & vacuumed the surface, though a thin film/dust remains.

What do you guys recommend to remove this? Light sponge mop w/ water? I noticed another thread mentioning denatured alcohol? Pressure washing @ this point would seem like a bad idea to me.

This article also mentions using diluted hydrogen peroxide:

http://www.ehow.com/way_5932989_concrete-dust-removal.html

The particles in concrete dust are very fine; simply vacuuming will not remove it all. Use a liquid to remove all of the dust. Dilute 12 ounces of hydrogen peroxide in 1 gallon of water and use soft cotton rags to wipe the surfaces. Water alone doesn't pick up all of the particles and requires multiple cleanings; this solution actually suspends the particles, and makes it easier for the rag to absorb them.

Thoughts?

 

[Edger]

A small amount of detergent with water, wet the floor and rinse off. If you can, agitate by walking up and down with a fine bristle broom head on the floor ahead of you both with detergent and with rinsing.

It is commonly thought that a stiff bristle broom is best, but they are next to useless, a fine bristled house broom is best because the fine bristles get into the small cracks and crevices and rides up and down the bumps whereas a stiff bristle skips over them. Another thing is that stiff bristles carry no liquid, but fine bristles hold lots of liquid.

The very best you can do is apply the detergent liquid, agitate with a broom and wet vacuum off. Rinse, agitate and vacuum off again. That gets the fine dust out of all the pores.

Forget about Hydrogen Peroxide, use a liquid detergent, not very strong.

 

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Thanks Edger. That seemed to work good.

The floor is now down! That was certainly a workout. The spiked shoes were slippery, I'm surprised none of us wiped out completely. The stupid nuts worked themselves loose, so we were having to pick them up here & there, what a pain.

I will post some photos once I have the opportunity. I certainly hope this floor stays down!

 

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Not the best photos, but here is the final job:

There is a total of 11lbs used on ~440sq ft. We did screw up flaking in a couple spots... grabbing from our containers it was easy to get carried away and dropped a few dense clumps (not really visible in the photo so much). Still, I think it has turned out great.

A closeup of the garage door threshold:

There were three of us putting the epoxy down - we decided to do the whole floor in one go. Rehearsing roles & responsibilities beforehand was certainly key - knowing what people would be doing & when helped out to maximize time (and mostly ensure we weren't yelling at one another trying to figure things out whilst doing it!)

The Epoxy Master's kit (via Costco.ca) coverage was as advertised. We probably had extra really. If we had divided the kit into a few sections, we probably could have used some on the stairs or stem walls.

As I mentioned before, the nuts on the spiked shoes came loose while walking around. Far worse for my father in law, who is 6'3" and not light on his feet. So even if those feel tight, you may want to check each one &/or put some locktite on the threads well beforehand to ensure they don't come off on you. We both felt like we were being very careful, but those things are really like ice skates while the epoxy is fresh.

I'll have to tackle the large stem walls & staircase at another time, perhaps next weekend. I may use a cheaper epoxy since they won't be seeing as much activity as the floors.

It is a nice sunny day today ~30C, though will be raining & cool Tuesday through Thursday. I don't think I'll even think about moving the cars in until Friday or Saturday. It does seem to be curing nicely though.