[modhatter]

I have a LARGE patio area surrounding a large in ground spa that previous owner painted with
OCEAN BLUE POOL PAINT (I'm guessing maybe total 800 sq. ft). Paint is meant for painting pools not cool deck patios. Didn't know he used this type of paint, so originally thought i could just repaint it with a more neutral beige color.

So after finding the paint can used as paint for the patio, I am now thinking that I have to have it sandblasted to have paint removed before I can do anything to it. However some of the cool decking material is coming up on one corner, so I fear sandblasting will remove cool decking as well. What to do? What to do?

Anyone ever have any large concrete areas sandblasted for paint or stain removal here? How costly was it?
Any recommendations of who to call. Since it is very old concrete, I'm beginning to think it might not cost substantially more to have it all removed and poor new.

[WestieJeff]

Have you tried power washing?

I'd be extremely surprised if it was cheaper to remove the existing concrete and pour new vs having kooldeck/spraydeck put over the existing concrete. Removing existing concrete is hard work and you have to deal with disposing all the old concrete.

I'm assuming they could probably just power wash the existing paint and spraydeck over it. They then paint over the spray decking (at least on mine they did). I paid about $3/sf, but the job was subpar. One of the spraydeck guys I talked to, he said they use a diamond grinder to grind down the existing kooldeck and then apply the spray deck. That guy wanted closer to $6/sf.

[irishspy]

Try going to a real Paint store not the box stores and see if they have a primer that will cover the bottom existing layer of paint and then what to use for a top coat. The primer is referred to as a sandwich coat. I am sure they will advise power washing first. This is similar to a wood deck that was painted and now you want to stain it. Please use a professional paint store for advise because many employees in box stores are part time and do not have the training or resources to tap into for advise to you. The professional store is where many good paint contractors get their information to assist them to be successful. One thing you did not mention is what type of paint was used on your project was it epoxy oil or latex that also makes a difference so make sure you have as much info to help in the decision making.

[SportyandMisty]

Paint makes a mechanical bond with concrete (unlike, say, two-part expoxies which make a chemical bond with concrete).

The best way to prepare concrete for a new coating is to remove the old coating. 3 common ways to remove the old coating are powerwashing, diamond grinding (rent a diamond grinder from a tool rental company), and bead blasting (rent a bead blaster from a tool rental company).

Bead blasting is best done by someone with experience -- otherwise you can end up with "corn rows" in the top texture of the concrete.

Using a stand-up grinder is a lot of work - you also attach a shop vac to it to vacuum the dust. Some people use a small hand-held angle grinder with an attachment to keep it level while you work - but this is back breaking labor.

In every case, you want to remove some of the top of the concrete -- about the thickness of two or three sheets of printer paper. This top layer is called "laitance" so that the fresh coat of paint you apply has something stronger to which to grip. You also want the surface to have a texture that is pretty much like 80 to 100 grit sandpaper -- this gives the new paint a better surface to grip. You don't want the resultant concrete to be polished if you plan to repaint it. Polished concrete outside would be slippery when wet, but looks beautiful for indoor applications.

The type of contractor you want to hire is a concrete grinder. Google is your friend. When they are done grinding, you repaint it yourself.

Another way to go would be to hire a contractor that specializes in epoxying garage floors. They have the equipment & experience to do the entire job. Note that you do not want epoxy outside - it will yellow over time with exposure to UV light. But they have the expertise to apply other coatings besides epoxy, including a paint.

Before doing a project, I suggest learning more. Do a google search for "concrete forums" and you will find several where you can read & learn & ask questions.

[modhatter]

Thanks for the information. Yes, I have been doing a lot of reading about it. Had someone out here just now that was quoting $6.00 a sq. ft. for grinding it, and re-texturing it. With all the other work I have to do in the yard (It needs everything) This is not what I wanted to hear. I could only find one company that did this. Anyone know anyone that just does the grinding?