Frustrating project - any suggestions?

[os1kne]

Our home is about 50 years old. We've lived here a bit over 6 years and have painted, remodeled, landscaped... darn near everything. We're planning to move in the next year or so. One feature of the house that we've never been crazy about is the front porch. If we were planning to stay several years, we'd probably build a new porch, but it's not worth the trouble for our remaining time.

The porch is painted concrete and has been peeling badly, so I've been working on scraping / removing the old paint and repainting. I have spent 2 gallons of stripper and many hours of squatting and scraping, using a heat gun, etc. - and have only been able to get ~ 90% of the paint up. My last 2 attempts to remove paint have been virtually fruitless, way beyond the point of diminishing returns, so I figured that everything that would come up had done so. I put on a coat of paint today and it doesn't look very good - it's pretty easy to see the areas where the paint didn't come up (I used a darker color). Any suggestions? Thanks.

[pelligrini]

Sandblast or a good water blaster should get the paint off.

[Mr__Bill]

I went through much the same with a patio. A 3000 psi pressure washer (Honda 11hp from neighbor) took off most of the paint but some was just not going to come off, even with paint stripper. I wound up using a non skid texture paint, that hides most of it. For your walls I think I would have tried to stucco it but now with a coat of paint perhaps something with texture, kind of like knock-down used on interior surfaces might work.

I tried to sand blast too, just took off the top of the concrete around the paint and left the paint. It's really too bad the original paint did not all stick like that, but much of it came off in big chunks.

good luck
Bill

[chopnhack]

As Mr. Bill said, power washer, - I rented one from HD with a floor cleaner attachment - it looked like a small lawn mower, underneath it had a spinning water jet. It worked wonders, without leaving me soaked. Do get the big power washer though.

[cabinetman]

As suggested, power washers can do wonders, but the down side is that you may get water blasts in areas you don't want. They can be very destructive. I would try a different stripper. I've had very good luck with an MC based (methylene chloride) stripper called "Aircraft Stripper". It comes in a blue can and I've only found it in automotive paint supply and body repair supply stores.

It's toxic as all get out, and you must follow the instructions closely. Old paint saturates the pores of the concrete and power washing doesn't always get to that depth of penetration. It would have to remove the surface to the level of the paint. A good stripper will saturate the concrete. Before using, the surface must be totally dry to get the maximum benefit.

I would continue with the stripper. If that continues to leave paint, try some HCL (hydrochloric acid). You can get a version of it cheaply at a pool supply store. That will get into the concrete and dissolve whatever is in the pores. It too is very toxic and has to be dispersed and handled with care. It will produce a low level toxic gas, so ventilation is necessary. It can be neutralized with water.

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[os1kne]

Thank you - some great suggestions. I'll probably leave it as is until spring and then tackle it again. After all the work that I've done, I don't really feel like stripping off the paint that I've just put down - even though that's what needs to be done. We won't have too many more nice weekends for working outside and I've got other outdoor projects that I need to get to.

[JSUPreston]

I've got the same problem with my front porch. I was wondering is using the ROS with 60 grit might get up what my pressure washer missed. If not, I wonder if using Drylok (sp?) as a primer and then painting with the color would work.

[Stytooner]

A flooring sander that you rent could do the job.
Definitely smooth it out for you. My experience with paint on concrete has been dismal.
Even epoxy coatings don't last forever.
Painting is quick and dirty though if you want curb appeal.
Otherwise a colored masonry application might end the frustration.

[frumper64]

Been there - done that

I went through the same thing on our concrete front porch. I simply could not get all the old paint off. I finally gave up and tiled it with slate. Fortunately, it was a fairly small porch, so it didn't get too expensive.

[pelligrini]

After all the work that I've done, I don't really feel like stripping off the paint that I've just put down - even though that's what needs to be done.

You might consider masking the good area around your trouble spots and blast or powerwash the places that need fixed. Scoring the stubborn spots with a utility knife before using a power washer or sandblaster can help too. You should be able to just repaint your newly cleaned areas. If you wait until next year you'd probably have to do the whole thing. UV and weather exposure wouldn't make color matching very easy.