Pre-Epoxy Floor Prep

[Southbound35]

This fall, I'll be epoxying our 3 car garage. Its a 14 year-old house with fairly typical oil stains, paint splatter, etc on the garage floor. My question is, which of the following three methods would be best for prep: power wash, concrete grinder, or scarifier? My research seems to tell me that the power washing may not be enough and the scarifier may be too much (it removes 1/8 of an inch of concrete), leaving the grinder as the best option. This would obviously be followed by de-greasing, acid etch, etc as recommended by the epoxy systems I've researched. Any advice or recommendations are appreciated. TIA.

 

[tncatadjuster]

Use the search a little more, the latest craze is to use a diamabrush. Lot's of info if you look.

 

[Shea]

If you have any heavy grease stains, it's best to try and get those out the best you can first. Power washing is fine for that but it is not a good method for prepping concrete. Grinding of the concrete for DIY is the best method. A grinder such as a Diamabrush on a floor buffer, 7" angle grinder with concrete cup wheel, or a 10" Edco are all good examples of equipment.

Acid etching is not required if you are going to grind. Etching is the alternative to grinding if you don't have the means to grind.

 

[Garage Flooring]

This fall, I'll be epoxying our 3 car garage. Its a 14 year-old house with fairly typical oil stains, paint splatter, etc on the garage floor. My question is, which of the following three methods would be best for prep: power wash, concrete grinder, or scarifier? My research seems to tell me that the power washing may not be enough and the scarifier may be too much (it removes 1/8 of an inch of concrete), leaving the grinder as the best option. This would obviously be followed by de-greasing, acid etch, etc as recommended by the epoxy systems I've researched. Any advice or recommendations are appreciated. TIA.

If you have any heavy grease stains, it's best to try and get those out the best you can first. Power washing is fine for that but it is not a good method for prepping concrete. Grinding of the concrete for DIY is the best method. A grinder such as a Diamabrush on a floor buffer, 7" angle grinder with concrete cup wheel, or a 10" Edco are all good examples of equipment.

Acid etching is not required if you are going to grind. Etching is the alternative to grinding if you don't have the means to grind.

Shea is dead on as usual BUT figure out what system you want first and then verify prep with the supplier.

 

[Southbound35]

Thanks for all the quick replies. I do have a 7" angle grinder but I'm not sure I want to tackle my entire floor with such a small tool, I thought the floor grinder might go faster. Any reason a Diamabrush is better than a regular floor grinder?

Also, I was under the impression that acid etching was in addition to grinding first. Since my floor is soiled but not awful, I may just plan on scrubbing well with de-greaser then doing the acid etch. Is the best way to test if the floor is ready to epoxy to ensure it absorbs water? Is there a better way to tell?

 

[benwah]

Diamabrush is the actual wheel that attaches to the floor machine.

If you are going to grind your floor acid-etching beforehand is a pointless step. You don't gain anything from it....Since you will be grinding....

Once the floor feels like rough sandpaper and readily absorbs water you will be ready to apply your coatings.

 

[LegacyIndustrial]

For the record, scarifying is a good prep method for trowel down mortar systems, not so good for coatings by themselves.

 

[mustangmatt]

Thanks for all the quick replies. I do have a 7" angle grinder but I'm not sure I want to tackle my entire floor with such a small tool, I thought the floor grinder might go faster. Any reason a Diamabrush is better than a regular floor grinder?

Also, I was under the impression that acid etching was in addition to grinding first. Since my floor is soiled but not awful, I may just plan on scrubbing well with de-greaser then doing the acid etch. Is the best way to test if the floor is ready to epoxy to ensure it absorbs water? Is there a better way to tell?

Im in the middle of doing a 1000' myself... Anything besides a floor machine would be complete insanity. I am using a diamabrush with clarke machine rental from Home Depot...

 

[Armorpoxy]

Stay away from scarifiers, they are very aggressive and will make your floor look like the moon, so unless you want to grind it down after scarifying, use a grinder.

While the Diamabrush is a good tool, its basically a 'scratcher' and not a 'grinder'. It doesn't have enough downward weight on it as there is only a floor buffer on top of it. A true grinder has a minimum of 200 lbs of downward weight and preferably more, so a floor buffer is a bit limited as to what it can accomplish if any real grinding is needed. We carry the Diamabrush and do sell quite a few of them but for serious grinding, rent a grinder.

 

[mustangmatt]

Stay away from scarifiers, they are very aggressive and will make your floor look like the moon, so unless you want to grind it down after scarifying, use a grinder.

While the Diamabrush is a good tool, its basically a 'scratcher' and not a 'grinder'. It doesn't have enough downward weight on it as there is only a floor buffer on top of it. A true grinder has a minimum of 200 lbs of downward weight and preferably more, so a floor buffer is a bit limited as to what it can accomplish if any real grinding is needed. We carry the Diamabrush and do sell quite a few of them but for serious grinding, rent a grinder.

Umm... should I be using something different for my own project then the diamabrush?!?!

 

[Armorpoxy]

No, they work fine, but if there is a lot of material to be removed or the floor smoothed out, we haven't seen Diamabrush do as much or takes much longer.

We are probably a bit jaded as to grinders ,as we use for our Prep-Crete Division are a fleet of Prepmaster Brand 40 HP 3 phase grinders with AC drive speed controls. They weigh 1,200 lbs each. These are the same grinders used for Terrazzo like is installed in airports.

Our smallest grinders we use are HTC 500's which weigh in at 325 lbs, and have 50 lb weights that can be added for more pressure. We use these for basements and such where we have to carry in the equipment and there are no elevators or other access, or 3 phase power available.

A floor buffer with diamond pad will work great for garage floors for texturizing them and grinding the concrete cap for excellent adhesion. If you are looking to grind to 'fix' a floor, then in our opinion a Diamabrush will do very little, at least in a reasonable amount of time. A Diamabrush will also do very little on aggregate/stone. The Edco type or similar smaller grinders with more weight and downward pressure will work well on a garage floor.

We find that a 7000 RPM 7-inch hand grinder with a 20 segment diamond turbo wheel and a dust shroud will do quite a bit of grinding to a floor, and repairs to the floor and grind into aggregate, as there are more diamonds on the surface, and it's spinning much faster. Just our opinion!

Below is a pic of the Prepmasters being used when we refinished part of the floors at New York's Penn Station. 28,000 square feet of granite to be grinded and polished at night when the trains stopped. Fun to look at!

 

[Shea]

The diamabrush is a great concrete surface prep tool for epoxy and probably the easiest to use. It works great for 95% of most garage floors.

We have an article about it here.

It is not to be used for taking out high spots in a slab or for leveling uneven surfaces however. For that you would want a more aggressive grinder.

 

[Armorpoxy]

We agree with Shea, Diamabrush is great for most projects, our note above is just to have reasonable expectations for the tool you are using, especially if the floor is in bad condition. We are saying the same thing, a Diamabrush won't do much to 'fix' a floor exactly as stated above.

 

[Garage Flooring]

The diamabrush is a great concrete surface prep tool for epoxy and probably the easiest to use. It works great for 95% of most garage floors.

We have an article about it here.

It is not to be used for taking out high spots in a slab or for leveling uneven surfaces however. For that you would want a more aggressive grinder.

Well said

 

[Denwood]

I used the Diamabrush, and would agree that it's good for prep, not good if you want to level, or take down a nasty finish.

My neighbor did grinding on his floor with a 220V, two-man lift grinder, and did his 30x30 in a few hours. The larger unit took his floor down to aggregate and left a very nice finish which he left as is.

I rented the diamabrush from HD, spent a lot more time, and took down far less material. Doing it again, I'd skip my ghetto vacuum solution and just do it wet. I duct taped a 50lb box of nails onto the floor polisher to help with the process. You can see the setup below. My floor grind thread is here: http://www.garagejournal.com/forum/showthread.php?p=4640280

So if your slab has a nice finish, and you're not leveling, the Diamabrush is fine. Otherwise, rent a larger grinder.

During the grind:

After finishing:

 

[Armorpoxy]

Beautiful garage! We totally agree and most of us seem to concur on what the Diamabrush will and won't do. Again, our only reason for clarifying this is to help to prevent someone from renting a Diamabrush if they needed repairs, leveling, etc. We would hate to see the waste of time/money!

 

[INTMD8]

Im in the middle of doing a 1000' myself... Anything besides a floor machine would be complete insanity. I am using a diamabrush with clarke machine rental from Home Depot...

After doing 1700sq/ft with a 7" diamabrush I can't argue with that (the insanity part).

My floor was too uneven (and possibly too hard) for the big diamabrush and the floor machine.

 

[ddewey78]

After doing 1700sq/ft with a 7" diamabrush I can't argue with that (the insanity part).

My floor was too uneven (and possibly too hard) for the big diamabrush and the floor machine.

I agree with the insane part, and i am only doing 450sq/ft. my local home depots dont have the floor machine with dust shroud, and i dont want to deal with doing it wet (plus with the california drought, im sure someone would report me)

But I will say i have noticed the diama brush taking some high spots down, that i dont know a big tool would have touched. I have done about 175-200 sq/ft and am on hold till the dust deputy gets here tomorrow.

 

[LegacyIndustrial]

We commonly use the Diamabrush for light removals and raw concrete.
It works very well on our Southern Concrete! Yes there is a difference from one area of the country to another. We commonly pull 100-150 lbs of crete-dust from a 700-900 sq ft garage, I'd say that's a bit more than a scratch!!

 

[ddewey78]

I feel so much better about myself now. If Legacy can get away using duct tape on their shop vac hose it must be OK!!

 

[LegacyIndustrial]

Duct tape makes the world go round!!


Sent from my iPhone using Tapatalk

 

[Armorpoxy]

Seems like we are all saying the same thing here. A Diamabrush will do very well sanding and light grinding of the 'cap' or 'cream' of decent or soft concrete, but if the job is problematic, has aggregate showing, needs repair, leveling and smoothing, most likely it won't do the job. The diamond blades sit on 'spring steel' which absorbs some of the downward weight, making them less efficient than a diamond floor grinder.

Also we find that rental Diamabrushes may have worn blades on them so try to get your local rental place to put new blades on them if they seem worn. We have had reports come in of rental Diamabrushes with blades that were almost completely worn out, so it's a good idea to see how the grit looks on them, and maybe compare to a new set that they have and make your case to the Salesperson to change them for you if needed. This extra step can save hours of back/forth to swap out the tool.

 

[Southbound35]

Guys, thanks for all the good advice. After looking more closely at my garage floor last night, I think it will be in my best interest to rent a Diamabrush/floor polisher at HD and use that for prep.

One further question. After searching and reading a number a previous posts on the grinding method, it seems some of the pros on here recommend doing a concrete primer coat prior to the epoxy. I've been looking hard at Epoxy-Coat brand flooring and they say nothing about any pre-epoxy primer. Is this necessary, and if so, will one brand of primer work better with certain brands of epoxy?

 

[Armorpoxy]

Hi
In our opinion when you grind a floor you should always prime. The reason for this is that grinding/mechanical prep 'opens up' the floor making it porous. In addition, uneven grinding (hard to avoid) can cause differences in porosity which will lead to a possible uneven finish due to absorption rate differences.

Our Armorclad 100% solids epoxy has a matching primer for it. If your supplier you are considering does not offer a matched primer, perhaps look at other systems mentioned on the board here.

Most recently there was a posting about a customer who bought some material from us, and another excellent supplier, but had problems due to installation issues and this led to a lot of back/forth as to responsibility. Even if a supplier 'says' that their primer is compatible with the brand you had noted, our opinion would be to reconsider a full and complete system from a single source.

 

[mustangmatt]

No, they work fine, but if there is a lot of material to be removed or the floor smoothed out, we haven't seen Diamabrush do as much or takes much longer.

We are probably a bit jaded as to grinders ,as we use for our Prep-Crete Division are a fleet of Prepmaster Brand 40 HP 3 phase grinders with AC drive speed controls. They weigh 1,200 lbs each. These are the same grinders used for Terrazzo like is installed in airports.

Our smallest grinders we use are HTC 500's which weigh in at 325 lbs, and have 50 lb weights that can be added for more pressure. We use these for basements and such where we have to carry in the equipment and there are no elevators or other access, or 3 phase power available.

A floor buffer with diamond pad will work great for garage floors for texturizing them and grinding the concrete cap for excellent adhesion. If you are looking to grind to 'fix' a floor, then in our opinion a Diamabrush will do very little, at least in a reasonable amount of time. A Diamabrush will also do very little on aggregate/stone. The Edco type or similar smaller grinders with more weight and downward pressure will work well on a garage floor.

We find that a 7000 RPM 7-inch hand grinder with a 20 segment diamond turbo wheel and a dust shroud will do quite a bit of grinding to a floor, and repairs to the floor and grind into aggregate, as there are more diamonds on the surface, and it's spinning much faster. Just our opinion!

Below is a pic of the Prepmasters being used when we refinished part of the floors at New York's Penn Station. 28,000 square feet of granite to be grinded and polished at night when the trains stopped. Fun to look at!

Great information in this post thank you! I am curious if the 7" would have been faster albeit a bit more back breaking as I have spent a LOT of time grinding and it has been quite a slow process. I am hoping to have my single side done tonight and to have the putty sanded on 2 car side... Once that is done I will be doing final cleanup and hopefully applying product tomorrow!

The diamabrush is a great concrete surface prep tool for epoxy and probably the easiest to use. It works great for 95% of most garage floors.

We have an article about it here.

It is not to be used for taking out high spots in a slab or for leveling uneven surfaces however. For that you would want a more aggressive grinder.

Shea would some darker more stained spots be ok to just use the diambrush or should I use acid on it first then diamabrush to be safe?

After doing 1700sq/ft with a 7" diamabrush I can't argue with that (the insanity part).

My floor was too uneven (and possibly too hard) for the big diamabrush and the floor machine.

I seriously cant even imagine that... I thought I was all that was man after doing about 600 sqft last night with the big grinder then over two hours on my knees no pads on bare concrete filling in holes lol... How long did it take you with the 7" tool?

I agree with the insane part, and i am only doing 450sq/ft. my local home depots dont have the floor machine with dust shroud, and i dont want to deal with doing it wet (plus with the california drought, im sure someone would report me)

But I will say i have noticed the diama brush taking some high spots down, that i dont know a big tool would have touched. I have done about 175-200 sq/ft and am on hold till the dust deputy gets here tomorrow.

I think this is why I was taking so long to grind as my vac wasnt sucking everything up and I had to go over the whole surface with a different attachment to get all the dust up. I would like a dust deputy myself but I only have about 300 to go and wonder if it would be a waste of time or money, wish I had it before I started grinding...

Guys, thanks for all the good advice. After looking more closely at my garage floor last night, I think it will be in my best interest to rent a Diamabrush/floor polisher at HD and use that for prep.

One further question. After searching and reading a number a previous posts on the grinding method, it seems some of the pros on here recommend doing a concrete primer coat prior to the epoxy. I've been looking hard at Epoxy-Coat brand flooring and they say nothing about any pre-epoxy primer. Is this necessary, and if so, will one brand of primer work better with certain brands of epoxy?

Get the dust deputy or a bad *** vacuum it will save a lot of time!!! and easier to work! my .02$ !

 

[Southbound35]

After much further research, I'm currently leaning more toward Armorpoxy. They recommend using their primer prior to the basecoat, which I will certainly do.

I'm curious, though, about how primers work. It seems as though they extend the coverage of the basecoat by making the concrete less porous, i.e., filling in the pores. But all the epoxy brands I've researched say the concrete pores must be opened up in order for the epoxy to bond to the concrete. Aren't these two concepts at odds with one another?

 

[benwah]

The primer creates a mechanical bond with the concrete, your "basecoat" creates a chemical bond with the primer.

 

[LegacyIndustrial]

The (2) products bond and become one.
Go without a primer and roll the dice for a trip to "Bubble City".

 

[benwah]

^^ I've been there!!! It's a ****** trip

 

[LegacyIndustrial]

Lmao

 

[Garage Flooring]

The (2) products bond and become one.
Go without a primer and roll the dice for a trip to "Bubble City".

The primer creates a mechanical bond with the concrete, your "basecoat" creates a chemical bond with the primer.

What is absolutely amazing to me is the number of people who will call us, convinced they need '100% solids epoxy' and our 'best top coat' or even high end quartz and metallic systems that will balk at 2 or 3 $60 primers.

 

[Armorpoxy]

Concur completely with above. After all of the research and work and money for the coating selected, not getting a primer can in some cases lead to problems. Use of the proper epoxy primer eliminates 99% of POTENTIAL problems.

We have tens of thousands of installs not using primer, but when we get a complaint, it could have been rectified in advance most of the time and inexpensively by using a primer. Also light and highly pigmented colors a primer is strongly encouraged.

All of our commercial work we always specify a primer coat. Eliminates callbacks and unhappy customers.

 

[Shea]

Shea would some darker more stained spots be ok to just use the diambrush or should I use acid on it first then diamabrush to be safe?

Contrary to popular belief, acid is not a cleaner. If the stains are from oil, the acid won't even work. It just sits there. Just clean them the best you can and then use Diamabrush on them. As long as they absorb water afterwards you will be good to go.

For those still on the fence about an epoxy primer, you can read this article here that explains the benefits of what a primer will do for you.

 

[Southbound35]

Thanks again for all the replies. As mentioned, I'm definitely going to use the primer after cleaning/grinding. I was just wondering about the reaction that occurs between the primer/concrete/epoxy and now I understand.

And thank you to the Armorpoxy rep for your assistance. I'm planning on ordering soon.

 

[Armorpoxy]

Great, thank you! Let us know if you need anything else.