garage floor repair and prep

[vavet]

I have a 24 x 40 foot 2 car garage with bare concrete floor. I'd love to fix up the garage a bit. I've looked at a lot of pictures of garages and workshops with tiled and epoxied floors. They all look terrific.

My garage floor would require a lot of work before it could take anything. It has oil stains from automotive work as well as something that appears to be overspray from the previous owner painting something. I tried soaking it down with Simple Green and pressure washing the floor about a year ago. It came out cleaner, but the overspray was still there. There are also some low spots in the floor that I presume would need to be leveled before it could take a tile floor.

What is the best way to prepare the floor?
Do I need to grind it before I could add a thin layer to even out the low spots and build in a grade for drainage.
Can I even out the low spot with thin set or do I need to add a thin layer of cement?

 

[bansky]

a 50/50 muriatic acid and water wash is a good start

 

[Prepman]

I install garage epoxy floors for a living. If you want to install a drain, the pitching will probably require a professional.. A good squeeze is cheaper than a drain and pitching. The depressions can be located by covering the floor to level and penciling in the boarder of each depression. Grind the floor with a.diamond floor grinder, that can be rented. Consult with your local paint store, be sure to ask for recommendations from their industrial rep. Better yet let them recommend a good installer in your area. He can show you an array of decorative floor samples to choose from. He would be happy just to do the prep if you are still for the DIY.

 

[vavet]

I didn't mean to say that I wanted to install a floor drain, I just meant that I'd like the back of the garage to be slightly higher than the front so that water will tend to drain out. I think this is building code in most places, but I'm not sure of the correct amount.

 

[LegacyIndustrial]

Changing the grade inside a garage once the floor is poured is not something I would recommend. It really should be done using polymer floor resurfacer as any cement based product would be weak. This is commonly done in food/beverage plants.

1/8" on the foot to easily move water with a squeegee.
1/4" on the foot to move by itself.

2006 IRC
R309.3 Floor surface.
Garage floor surfaces shall be of approved noncombustible material.
The area of floor used for parking of automobiles or other vehicles shall be sloped to facilitate the movement of liquids to a drain or toward the main vehicle entry doorway.

 

[pauloman]

With over 20 years in the epoxy business, my worry is the grease and oil stains. In some cases they can be so bad that nothing works and all the coatings over them will peel up in weeks or months.
A common trick is the water test, pour water onto the cleaned site. If it beads up, you're still in trouble (if it doen't you still could be in trouble). Best advice is to probably clean and coat with a solvent free epoxy - let it sit for a few months and see what happens.

a solvent free epoxy also means wet thickness equals dry thickness. So you can put it on thick enough to self level the low spots. Note that 1 gallon of anything only covers 6.2 sq feet at 1/4 inch thick.

The comments about muriatic acid above are wrong. The acid sells at 31% conc, correct use on floors is 10% conc. Note that acid treating only adds surface profile, not oil removal, cleaning etc.

see more at www.epoxyproducts.com/floorlinks.html

paul

 

[LegacyIndustrial]

Paul: your twenty years in the business equates to bunk.
A solvent free epoxy has an equal wet and dry mils thickness???

A waterborne epoxy is solvent free. Does this hold true? No it does not.

Now you are telling people that epoxy coating will fill low spots? It will not.

Low spots will continue to be low unless addressed properly prior to coating.

Do all the DIY a favor and run your theories by a real installer to make sure they are correct first. You are going to steer someone in the wrong direction, causing grief.

 

[theoldwizard1]

... my worry is the grease and oil stains.

Same here.

I have had very good luck with 2 products, Greased Lightning and Drive Up.

Spray it on the area, scrub in with a push broom, let dry overnight and rinse. Let the area dry well. You may have to repeat the above process.

As other have said, changing the pitch of the floor will be difficult. If your goal is to make an area level for tile that is not that hard. They do make "self leveling cement" for that purpose. Follow the manufactures directions, but you probably have to grind/treat with muriatic acid, and apply a bonding agent before applying the self leveling cement.

If you are only going to be doing one area, you will need dams to prevent the self leveling cement from running out of the area.

 

[pauloman]

#7 is certainly mis-informed!!!
yes, with solvent free epoxies - wet thickness equals dry thickness. 10 mils of wet epoxy becomes 10 mils of hard epoxy. An epoxy that is 25% solvent (25 % voc) will shrink by 25% as the solvents flash off. Research dmt (dry mil thickness) vs wmt (wet mil thickness).

Epoxy, albeit expensive, is used (often mixed with sand to bulk it up) to level floors - again because you get it level and if solvent free - it stays that way. I could quote you on 'epoxy underlayment right now.

with waterborne epoxies - water is the solvent - actually most such epoxies are 50% or so water. Water is a solvent but not a VOC regulated solvent.

Note that waterborne is not the same as waterbased. Waterborne epoxies contain traditional solvents as well as water. My waterborne floor epoxy, as an example, contains enough voc solvents that I cannot sell it in southern calif.

#7 - suggest you do your homework. I've been running a successful epoxy business with clients from nuclear power plants to the US navy, to major petroluem pipeline companies to world sailing yacht builders. have also worked with folks that have done thousands and thousands of epoxy post office floors.

I have an ms in science, as well as an MBA. would you like a list of my epoxy articles in various trade and professional magazines over the last 20 years?

I post to pass along information, your posts seem to be about pushing your web site

 

[LegacyIndustrial]

Paul:
It's 2012, we all went to college.
We can claim power plants, piggly wiggly and Ford too. Big deal.

Your original response was vague enough to steer someone in the wrong direction.

I didn't push anything but your vagueness.

 

[cj7365]

 

[dandan111]

This flooring thread is a real ball buster sometimes. The other threads are more laid back.

 

[pauls340]

yea, but with those other threads you fall asleep....this is fun !!