Stony concrete for epoxy.

[david1pro]

Hi,

I am considering using Epoxy-Coat for my garage floor. The garage floor is, I believe, currently coated with garage paint and some flakes. The paint has come up in several rough spots, but is adhering fine where the concrete is more or less smooth. The rough spots are spots where the original pour seems to have been poorly done, and there are many small stones at the surface of the concrete. I don't believe it would be possible to grind this smooth, as you would simply chip out all the stones leaving an even rougher floor (which is otherwise known as my driveway). There are no cracks in the floor, save the two expansion joints dividing the floor into four sections. The floor is 30 years old. The floor is clean, with no obvious evidence of oil or other spill spots.

While I would love to have a perfectly smooth floor, I don't know that this is possible. How well will the 100 percent epoxy adhere to the stony surface? Will it smooth it somewhat?

I have three images here, as pictures are always better than words:

I believe I am comfortable with putting on the epoxy. I will be doing this alone and I do wonder if grinding is above what I can afford and do. Epoxy-Coat seems to state that sandpaper on existing coats is good enough. I don't believe the floor has been sealed... just painted. The paint is not actively peeling anywhere. It simply has come up on the rough spots in the past. I've had the house two years, and with active use and a car in and out, there has been no real change.

Suggestions/advice for a man with only himself to work with and not too much money to spend?

 

[AlphaGarage]

I can only speak specifically about Wolverine products, and you really should pose your questions to the supplier of the product you intend to use, but with that in mind...

The current coating seems like it's less than ideal - although much of the wear can probably be attributed to wear on high spots (which really shouldn't be that much of a problem), I'd venture to say that some of it has had a failure of adhesion also.

Keeping that in mind I'd opt to remove all traces of the current coating. A quality epoxy primer will have no problems adhering to properly prepped concrete or aggregates in the concrete, it will also adhere to the current coating, but when any of the current coating fails and releases, your new coating will probably come up with it.

Grinding will level things out a bit, and shouldn't pull up too much aggregate out of the concrete. Plus a high build epoxy system will fill, level, and smooth out irregularities to a point. Adding a good broadcast of flakes will also go a long way to providing a smooth looking finished project.

Most of us can appreciate being on a budget, but having limited funds is exactly the reason to do the job right the first time, because nothing is more costly that finding yourself in the position of needing to do it yet again to get it right a second time.

From the pictures it's clear that your substrate does have a high level of aggregate. Rocks, gravel, can be a lot smoother than concrete. So be sure to use a coating that not only physically bonds to stone, but also chemically adheres to the substrate, not all of them do that.

 

[35mastr]

Fred hit right on the nail here.

I can only speak specifically about Wolverine products, and you really should pose your questions to the supplier of the product you intend to use, but with that in mind...

The current coating seems like it's less than ideal - although much of the wear can probably be attributed to wear on high spots (which really shouldn't be that much of a problem), I'd venture to say that some of it has had a failure of adhesion also.

Keeping that in mind I'd opt to remove all traces of the current coating. A quality epoxy primer will have no problems adhering to properly prepped concrete or aggregates in the concrete, it will also adhere to the current coating, but when any of the current coating fails and releases, your new coating will probably come up with it.

Grinding will level things out a bit, and shouldn't pull up too much aggregate out of the concrete. Plus a high build epoxy system will fill, level, and smooth out irregularities to a point. Adding a good broadcast of flakes will also go a long way to providing a smooth looking finished project.

Most of us can appreciate being on a budget, but having limited funds is exactly the reason to do the job right the first time, because nothing is more costly that finding yourself in the position of needing to do it yet again to get it right a second time.
From the pictures it's clear that your substrate does have a high level of aggregate. Rocks, gravel, can be a lot smoother than concrete. So be sure to use a coating that not only physically bonds to stone, but also chemically adheres to the substrate, not all of them do that.

 

[thegarageguy]

Solvent epoxies roll out thin, 100% solids can be poured but they self level to an 1/8 inch or less. To build it up to hide your deterioration you would have to use fillers or aggregates or multiple coats. Chips would only hide so much.

When we run into situations like yours, we recommend resurfacing with a urethane cement. It gets raked out at 1/2 inch thick and self levels to 1/4 inch. Broadcast right into it and seal.

It's not DIY and not cheap but when a surface is that far deteriorated, it is the best choice. IMPO

 

[Doug_Fir]

I agree with grinding off the old product. Your floor is only as good as the weakest link.

A lot of commercial contractors in my region use Ardex brand products for concrete restoration (I'm not affiliated with them in any way), and I'm sure there are comparable products from other companies. Look at their Ardex CD Fine (http://www.ardex.com/productDetail....tParentID=2&ProductCategoryID=24&ProductID=27) and consider a light broom finish for the epoxy primer. I also see a lot of Ardex Feather Finish, which can taper to zero thickness. You obviously still need to make sure the overlay will adhere to the existing substrate, which I doubt a light sanding would be good enough. I know Ardex products aren't cheap, but there's a reason they are popular here.

 

[david1pro]

As mentioned earlier, I did ask the the guys at Epoxy-Coat. I received a quick response which I will paste below for those interested:

Hi David,

I understand your concerns with grinding the floor but let me reassure you that grinding will be a very good option for you. I personally have an outside patio at my home which was probably poured in the 70s. It was an exposed aggregate surface, similar to what you have, although not as bad. I took a grinder to it and it actually did smooth out the surface (to my amazement) very well. I think our product would work well for your application but I would highly suggest diamond grinding the surface, which you can typically rent from Home Depot or any other local rental store and then after grinding the surface I would also recommend acid washing the concrete with muriatic acid (which is what our prep solution is). By acid washing the area afterwards you can ensure that the deeper part of the stones where the grinder does not get too will be etched so the epoxy will adhere properly to the aggregate part. Depending on how well you can level out that are with the grinder you may end up having to apply the epoxy a bit thicker in those areas.

If you have any other questions or concerns please do not hesitate to ask or if you’d like you can call the office at (800) 841-5580.