Advice on re-doing epoxy floor (long)

[jager911]

I've been reading the forum for a few years, enjoying the pictures and makeovers. I did my 20x30 garage floor 9 years ago when I built my house, i.e. new concrete, cured for 6 months. I used Sherwin Williams ArmorSeal 1000HS which is a high-solids 2 part epoxy. I did all the right prep, etching and washing and installed the SW primer coat. I think the weak point was I only used 1 color coat and no clear as I was on a budget with a new house. I'm guessing it was installed at 3-5 mils based on the SW data sheet.

The floor has seen heavy use rolling around large floor jack and engines etc.
It has abraded mostly where the tires sit and scratched and peeled in spots but it is firmly down in 90% but looking crappy with little pits.

I'm ready to re-do it and going with a product I have not seen mentioned here. My neighbor has had it down for 2 years without noticeable wear. It's Dynamis EPO Coat H3H 100% solids. Each coat is applied at 10mils.
I bought 5 gals for 2 coats of color and 3 gals for 1 coat of clear with flakes so I hope to finish around 30 mils. Does that sound like a good plan for longer term durability?

Questions:
1. I know I need to abrade/sand the floor to get a good mechanical bond but do I really need to rent a diamond stone grinder to take it all off? It's $160/day and I'm hoping I can get away with a good sanding and scraping of the loose areas. I plan to go through all the etch/wash prep, clean off oil etc.
2. Is it recommended to use anti-skid additive? This product is very glossy.
Has anyone installed clear without additive and regretted it?
3. Is 4 lbs of standard 1/4" flakes enough for medium coverage? I'm going for the granite look with gray base color.

I'm sure I'll have more questions as I get into the project. If you read this far, looking for constructive feedback.

 

[AlphaGarage]

Not familiar with the product, but fortunately the math is universal, and it breaks down like this...

Given:
~5 gallons pigmented top coat - 100% solids
~3 gallons clear coat - 100% solids
~600 ft2 of floor to be covered
~1,604 "mils" per gallon of liquid (any liquid)
~10% waste, material left in can, on brushes etc.

So...
5 + 3 = 8 gallons
8 * 1,604 = 12,832 total mils avail
12,832 - 10% waste = 11,548 net mils of material on floor
11,548 / 600 = 19.248

Therefore if you have exactly 8 gallons of 100% epoxy, and manage to keep waste to exactly 10%, and evenly coat exactly 600 square feet, the dry film thickness of all 3 layers of coating will be 19.248 mils.

Pop quiz to follow...



And here it is... What's motivating you to put down the pigmented epoxy in 2 layers of approx 6.6 mils instead of one 13 mil layer?

Times up - pencils down. For the correct answer I'd contact the manufacturer.

If it were LiquaTile 1184 I'd suggest a single thick layer as opposed to 2 thin layer because... 1 - a thick layer will do a better job of covering peaks and valleys. 2 - it will take less time & effort. 3 - One less layer intersection to go wrong. 4 - no compelling advantage to doing multiple layers. It would be a bit easier to spread and backroll a thinner layer, but that benefit is not offset by the time & effort it takes to do it twice - twice the measuring, twice the mixing, twice the application, twice the curing time to tack free, twice blah blah blah...

Clearing the decks. If It were me going through the expense, and time, and effort to clear off the floor etc., I wouldn't risk keeping any of the current coating! You have proof that it's not adhering that well, so why risk all the new expended resources on a flaky foundation? I vote for grinding it off and getting a 100% prepped, clean, pure, substrate to build on.

True Grit. I've had clients say they wish they had used grit, but none lamenting that they put it down, although a couple have said they put down too much. We spec 0.5 lbs for 200 ft2 on a commercial shop floor, but push that to 300 - 400 ft2 for typical residential garage applications.

Chips ahoy. Four lbs. of chips for 600 ft2 is pretty light flake density - it equals 0.0066 lbs per ft2. In my opinion it will not look like granite. Not saying it will look bad, it's actually a nice look - just not much like natural granite. You can get a sense of varying flake densities HERE (the samples are on 12" x 12" boards).

 

[rugerlady]

IMHO, Alpha is 100% on.

 

[jager911]

Fred,
Thanks for the detailed response.
My logic with 2 coats of color was based on the SW single coat over primer not holding up that well, I thought 2 coats will be thicker than 1. I didn't think of applying a single thicker coat. This product is very thick to work with and only has a pot life of 20-30 mins though it can be thinned with acetone to extend pot life to 1-2 hours. The manuf spec is 1 gal will cover 180 sq ft when applied at 10 mils, my neighbor used 3 gals and covered his 20x20 garage with 2 coats so I extrapolated I could get 2 coats with 5 gals, and 3 gals of clear should be enough but I didn't account for 10% waste. That's where I got 30 mils.
I'll assume your universal math is right as you do this for a living, is 19 mils a decent thickness? If I apply 1 thicker coat as you suggest, then I assume I'd have to mark off the garage in 5 sections, roll it out, sprinkle flakes, then repeat.
Grinding: I'd rather invest the time to ensure new coating doesn't fail so I guess I'll have to bite the bullet and take it all off. I may have to grind it in stages, moving cabinets and tools around and as time permits. I'd rather invest in a grinding tool than spend $160/day on renting unless the time savings is worth it, i.e. can 600 sq ft be removed in 1 day given I have a top coat and a primer to remove? If the grinding tool will take a week, then I'd rent if it can be done in 1 day.
On grit, I'll probably go with it so I don't have my wife kill herself on it.
On chips, after looking at your samples, looks like I need a lot more, that helps.

 

[AlphaGarage]

Well, the math is the math - pretty inflexible (until we start figuring floor dimension with non Euclidian geometry). It's easy, and a bit fruitless, to get hung up on the math, but for the record there is no way that 1 gallon will coat 180 ft2 to a depth of 10 mils, unless that liquid expands. To coat 180 ft2 to 10 mils would require 1,800 mils per gallon, and there are only 1,604. To do that would be a feat comparable to having a pound of gold an being able to melt it down into 18 individual one ounce ingots of 24 carat gold. A neat trick if you can pull it off, and if you can call me direct immediately because we can make some big money together!

Central to your concerns is the age old question "Is bigger better?" When it comes to floor coating, generally that answer is "yes," so all other factors being equal 19 mil of product will be more durable than 10 mils of the same product. But when it's suggested to check with the manufacturer for details, you really should, even when dealing with coating thickness. There are some products that behave badly when put down too thick, in our case our clear coat polyurethane "EnduraShield 2254" may develop small air bubbbles during the cure period if it's applied thicker than 10 mils, doesn't affect performance, but can be distracting with certain colors combos. And there are other coatings (not ones I'd sell to DIY) that will fail to cure if applied too thick.

Five sections might be one or two too many, 3 sections of 200 ft2 each should be easily manageable even for a single worker doing their first epoxy floor.

Grinding is your best path to follow, now whether you march down that path with your new angle grinder in hand, or walking behind a rental grinder, is strictly a personal preference call. As much as I love to justify adding to the tool collection, and I do, if I was facing 600 ft2 of existing coating I'd be calling rental yards and lining up a floor grinder for this Saturday. Most can't get into corners and right to the wall edges, so you may still want to consider a small grinder or palm sander.