Concrete Acid Stain & Scoring on the Exterior Porches

Click here to also see the aqua blue  house interior slab concrete acid stain treatement

I used concrete acid stain on the upper porch and interior floors, and was very pleased.

Now over a year later, the color is still wonderful. People really marvel at the concrete acid stained interior floor and like the effect of the selective acrylic coated diagonal stripes on the porches. As light hits the cross-bands where the acrylic sealer was used it creates a beautiful effect. See the photos lower on this page. Every magazine or newspaper that has featured photos of our project has included photos of the porches.

On the step between the porches, I wanted to have a little detail and the look of individual tiles so before I did the green stain, I hand painted some decorative elements in a color of stain darker than the green I planned to do overall. The score lines were done ahead of time by our concrete subcontractor. Be sure to mark them yourself, or have a good look at them before any cutting is done. To speed up the process of handpainting, I used a rubber stamp to stamp the design on the concrete with plain water, which momentarily darkened the surface in the shape of the stamp. I used a damp sponge to moisten the stamp evenly. It was a warm day and the water evaporated quickly, but was there long enough for me to see the outline.

As you can see, once the green stain was used over the handpainted designs, their effect was softened considerably.

On the lower porch, I brushed, Light Palmetto Green acid stain all over. I also sprinkled  lightly Sterns Miracle Grow for turquoise speckles.

In the cross hatch areas of my score lines, I had previously hand painted small sea shells and similar designs with the same dark brown acid stain as I used on the step. Once the Palmetto Green concrete acid stain residue was hosed off, the previously painted designs and the hand painted step 'tile' designs showed through softly. This porch and the step will need a second coat to have the deep color that you see here. (The colors appear more deep when wet.)

It is the random effect that the concrete acid stain has on troweled concrete that is a big part of it's beauty.

See the interior floors with additional concrete acid stain photos and info here.

I used this same color concrete acid stain on my baseboards that I poured myself from a home-made mold. I think they look 'mah-vah-lus dah-ling'

On my test piece, the lighter diagonal bands are the treated, and roughed -up areas. I did a couple test diagonal bands on the corner of one of the steps also, there the treated areas appear a bit darker.

After doing some internet reading, I decided that sprinkling a cheap breakfast cereal over the thickly applied muratic acid might result in deeper etching. With a brush, I applied the acid, full strength (31%), and shook rice cereal over them in a mottled distribution. I waited until the next morning to rinse the steps. It worked.

It is very important to wear googles & rubber gloves when working with this strong acid. When the full strength acid made contact with the concrete, the fizzing and bubbling was dramatic and the fumes were strong and toxic. The acid  even turned line-acid-green ,think "Roger Rabbit" & melting people. It was strong!

I was careful to not get the acid any place except the step treads. This shows the cereal sprinkled on the treads also.

The mottled effect gives good traction. Where the cereal was, it absorbed muratic acid and kept the acid in contact with the concrete for deeper etching. I have given the steps the 'wet flip-flop test' several times now, and no hydroplaneing as before.

On the south end of the porch, I used a different cereal, only because I had run out of the rice crispies and had bought several kinds in case one of them released some nutrient in the acid that caused discoloration (they didn't). I also found that once I had applied a heavy coat of muratic acid and sprinkled the cereal, I could easily add additional acid with a small plastic squirt bottle. I used a funnel to fill it and always wore rubber gloves and goggles.