Exterior Concrete Coatings

[Malcolm Hoar]

I have an entrance porch of approx 150 sq ft of mature (17 years) concrete. It's in generally sound condition with a few small cracks and chips but it's been stained by some planters that were placed there at one time.

Initially, I considered tiling the thing. However, that now looks less than practical due to a combination of drainage issues and expansion joints running at 45 degrees.

So then I started looking at various coatings. Google turned up a bunch of products some of which look a lot like overpriced snake oil. Sherwin Williams have the H&C Silicone Acrylic Concrete Sealer which looks like it would work but apparently it's not available in the People's Republic of Kalifornia. I feel it will probably take something of better quality than that sold in the big box stores.

I'd like to create something like a natural stone effect with a little texture/pattern (versus solid color) to hide the imperfections. The porch is sheltered from the wind and rain but exposed to direct sunlight and UV. Traffic is very light but I want something durable and don't need a maintenance liability.

I think it wants a relatively thick (high solids) coating to fill/hide the cracks and imperfections and maybe a clearcoat on top for additional protection -- I don't want the "wet look". I considered acid staining but at

17 years I fear the surface is too shabby for that to work out well. Ditto for semi-transparent stains.

I don't own any spray gear and prefer something that can be rolled on. I might even use a ragging roller and add a thin coat of a different color to create something of a granite-like texture.

Anyone have any experience of *exterior* concrete coatings? Many of the garage floor paints are not UV resistent!

[Joseph Meehan]

Frankly I would suggest not trying to cover it up. You will likely be disappointed in the long run.

Rather than cover it up, how about a good power washer to work on it or some sand blasting. Either should clean it up and it should look new again. Most products used on concrete that is exposed to the elements and freeze thaw cycles under up looking really bad really soon.

...

[Malcolm Hoar]

Yeah, that's a very valid concern.

I've tried the power washer -- with only 150 sq ft I was able to give a pretty thorough cleaning. It helped but still looks shabby.

A sand or shot blaster is an interesting idea. It might produce an acceptable result by itself. But it would almost certainly provide a good surface for some kind of penetrating semi- transparent stain too.

Freezing is not a major problem here in the San Francisco Bay Area.

[Steve]

[e-mail] (Malcolm Hoar) wrote on 14 Nov 2007 in group alt.home.repair:

Consider the gravel/epoxy coatings. They're effectively permanent, and they drain.

[Malcolm Hoar]

Hmmmm, I assume you're speaking of some kind of aggregate that's bound together and onto the old concrete with epoxy? I guess this would be troweled on rather than painted.

It's an interesting possibility. Do you know of any specific products?

[charlie]

pebble-tec. i've used this to cover concrete patios. it does work well. it is troweled on, so can be used on non-level concrete slabs well. however, it is hotter underfoot if in direct sun, and also the epoxy has to be renewed (at a fairly large expense) every 3-5 years. if you fail to renew the coating, the sun breaks down the epoxy and the pebbles start coming out of the coating.

regards, charlie cave creek, az

[Malcolm Hoar]

Thanks, I'll check that out. Applying a fresh coat of UV protecting clearcoat every few years would be okay. I don't want any more maintenance than that.

[trader4]

I used a solid stain for concrete on my stamped concrete patio. It's about 10 years old now and was getting weathered. Prior to this, I'd only used a clear sealer on it. It came out excellent, looks like new. I followed up with a solvent based sealer and iIt's been 18 months and it still looks good

[DanG]

You are launching into an area called decorative concrete.

Good, professional information here:

If you are subject to freeze/thaw I would avoid the glued on stone stuff. I can show you more failures than successes.