Repainting previously painted concrete porch

aquint · 03-10-2011, 02:08 PM

I live in an old house with a tile patterned concrete porch floor. Except in those areas that get enough traffic to wear the paint down, each "tile" seems to have anywhere between 3 and 7-8 layers of paint. Two years ago I scraped and wire brushed the concrete extensively before repainting it with oil based porch paint (previous paint layer was oil), but within a year it started to peel again. I was told that I should also use a power washer as a final prep step. I'm happy to try this, but hard pressed to imagine this will be sufficient to keep the paint from peeling again fairly quickly. Any thoughts on best way to proceed? I don't mind doing a lot if it means it won't have to be done so often. Also should it be primed, and if so, with what? I've also thought about using a two-part epoxy finish. Is there a way to get the existing surface to the point it's possible to do so?

Ole34 · 03-10-2011, 02:23 PM

do you have any pictures of said porch ???

aquint · 03-10-2011, 02:29 PM

I'm technologically challenged! I could take a picture, but I'd have to figure out how to upload(?) it.

housepaintingny · 03-10-2011, 02:53 PM

You don't want to use an oil base product on concrete, as it will cause what's called saponification, its basically a reaction where the coating will not adhere and bond properly. Using a pressure washer is a good idea. You want to first clean the surface real well with a concrete cleaner, something with a degreaser in it. Then you want to scrape away all loose and flaking paint. If the concrete is smooth you will want to etch the surface with a concrete etcher. Their are several products you can use. I prefer to use Sherwin Williams Shercrete on exterior concrete surfaces. It is the same product I use on concrete decking around in the ground pools.

aquint · 03-10-2011, 03:16 PM

Thank you for all the advice . I want to be sure of the sequence of steps. Do I use the power washer only before I scrape? Would power wash, scrape, then power wash again get even more off, or is there a point of diminishing returns? Should I rent one of the heavy duty washers, or is a home model sufficient? As far as the concrete goes, its the kind with little pebbles that make the surface rough, not smooth. Does this sound as though I don't have to worry about etching, or would it still be helpful?

housepaintingny · 03-10-2011, 03:22 PM

Quote:

Originally Posted by aquint

Thank you for all the advice . I want to be sure of the sequence of steps. Do I use the power washer only before I scrape? Would power wash, scrape, then power wash again get even more off, or is there a point of diminishing returns? Should I rent one of the heavy duty washers, or is a home model sufficient? As far as the concrete goes, its the kind with little pebbles that make the surface rough, not smooth. Does this sound as though I don't have to worry about etching, or would it still be helpful?

I like to wash the surface before and after scraping. But don't use high pressure. A small pressure washer will work fine. Sounds like you will not need to etch. You also don't have to prime. If you use the SW Shercrete you will apply two coats. Allow the concrete to dry completely after washing, before painting.