Epoxy on spalled concrete?

[my68spit]

Hey everyone. I have been speaking with my father regarding the 35+ year old concrete in his garage. It had a rough life with multiple project cars, and lots of regular maintenance on every other car that our family of 6 has owned over the years. The floor is in pretty poor condition over a majority of the floor. There is lots of spalling, oil stains and cracking. He is at a point now where the garage is no longer a work place so much as just a place to park the cars and he would like to clean it up and get it looking nice again. I mentioned doing the epoxy and he really liked the idea.
My initial brainstorming and searching the internet led me to this thought process:

1) pressure wash
2) acid wash
3) rent a grinder and go over the whole floor
4) self-leveling concrete over the whole floor
5) epoxy

Does this seem like a logical direction and series of steps? Is self-leveling concrete an OK idea for eventual Epoxy coating? Are there special kinds that should be considered? Should the new concrete be poured ONLY over the areas that are spalling?

We are open to any other ideas and suggestions.

I don't have any pictures of the garage now since I don't live there anymore but I can try to get some next time I am out there.

Thanks.

 

[AlphaGarage]

You might want to consider an epoxy filler to level things out. There's no 28 day wait, it adheres real well, it's extremely durable.

I'd acid etch or grind, no need for belt and suspenders.

Our kits are 1 gallon of 100% solids epoxy binder that you combine with 50 lbs. of locally sourced sand, it will fill 16 ft2 to a depth of 1/4 inch. You'd only need it in the spalled low areas, most likely no reason to use it on the areas that are solid and sound.

 

[Okolowicz]

You do not need to acid wash AND diamond grind. One or the other is done. However, diamond grinding is always better. And, considering the shape of the floor I would not even consider acid etching instead of grinding. Now, the steps:

1) degrease any areas that have had oil, fuel and or other contaminants.
2) diamond grind (the best tool to use is not a traditional concrete grinder. Instead, use a Diamabrush that is available for rent from Home Depot. It has diamond blades and attaches to a floor buffer to grind the concrete. Home Depot rents two different Diamabrush tools the Coating Removal Tool and the Prep Tool. If you do not need to remove any coats of paint, stain, or epoxy from the floor rent the Prep Tool.
3)vacuum
4)clean
5)use epoxy concrete patch and/or joint filler as needed. Only use an epoxy (two part) concrete patch. You can buy it from the epoxy vendors in gallon size tubs and up if you have a lot of repair work. I had a very small amount of repairs so, I bought something from Sherwin Williams called Sher-Crete. It had a two hour cure time and came in an 8.5oz tube. It is a lot more expensive than what the epoxy vendors sell but I did not want to wait for something to be shipped to me, as I already had all the other items needed.
6)Once the patch has cured you will likely want to grind those areas again. That is a benefit of the Sher-Crete stuff I used. Youi can rent the Diamabrush in the morning, grind, vacuum, clean, patch, wait 2 hours for patch to cure, and regrind the patched areas all within the 1-day rental time.
7)Now that you have ground the floor again you'll need to vacuum and clean again. Bear in mind that dust and water are the enemies. Once you have fully cleaned the floor and it is dry, take your finger and wipe it on the concrete to see if any dust appears on your finger, if it does you need to clean again.
8) Primer (Optional)
9) Epoxy
10) Clearcoat (Optional)

Other things:
- Cleaning: If you clean with floor with cleaner and water it would be wise to wait at least 24 hours, perhas ore to ensure the floor is fully dry before you put the epoxy down. Remember, water is an enemy. Another option is to not use water. After you have vacuumed thoroughly take a microfiber mop and apply some denatured alcohol to it and clean the floor with that. Keep a couple of mop pads around because you'll probably fill two up. And, keep mopping with denatured alcohol until there is no more dust.
- Primer is optional but highly recommended for a variety of reasons. Trust me you will not regret it.
- Clearcoat is also optional but largely depends on how much sun the area gets. if sun hits the floor it will yellow over time. a clear urethane topcoat will help prevent that.
- As you can see and you will experience, it is a LOT of work. Putting the epoxy down is rather easy in the scheme of things. the prep work is the most difficult. Another reason it is not worth skipping the primer. Too much time, effort and expense goes into this project to worry about another $100

 

[LegacyIndustrial]

If the surface is "crater like" or "pocked" it is common to apply an epoxy based self leveling coating. This is a 100% solids epoxy coating that is fortified with a fine silica aggregate.

It is typically gauge raked across the surface post prep. Once cured, a conventional solids coating is added, flake and clear as an option.

The result is a smooth, strong attractive floor.

Another method to smooth out a floor like this is a "broadcast" system.
Epoxy, broadcasted with sand to rejection, Epoxy, sand to rejection, epoxy.

Either is long lasting and tough!

 

[BFBOB]

Dunno if it's been said already, but I for one appreciate that pros in the business - yep, those evil commercial interests - reply to members' questions, AND clearly identify themselves.
Thanks!

 

[AlphaGarage]

- Cleaning: If you clean with floor with cleaner and water it would be wise to wait at least 24 hours, perhas ore to ensure the floor is fully dry before you put the epoxy down. Remember, water is an enemy. Another option is to not use water. After you have vacuumed thoroughly take a microfiber mop and apply some denatured alcohol to it and clean the floor with that. Keep a couple of mop pads around because you'll probably fill two up. And, keep mopping with denatured alcohol until there is no more dust.

Good advice, but I do need to point out that although most coatings do require bone dry concrete before application, not all of them do.

For our primer, BondTite 1101, we recommend that the floor can be damp, but not moist. So no standing water, and at least some of the floor looking light and dry. Depending on the weather and the concrete that can occur in just a couple of hours after rinsing. Although the concrete looks dry, that appearance is deceiving, concrete is like a sponge, the visible surface looks dry, inside it's still very wet, but that's okay for BondTite to be applied, it will still bond with the concrete.

 

[my68spit]

Thanks for the responses & the information guys. Sounds like my dad and I have our work cut out for us. I will definitely keep everyone posted when the project gets underway.