It’s possible that I almost had a minor breakdown when we had to choose the colors and patterns for the concrete that surrounds almost half of our house. Because the truth is, with decorative concrete these days, the patterns and color combinations are infinite. Which is exactly how I almost ended up with a very large very purple porch surrounding my house.
Oh wait, I’m sorry, plum.
A plum porch surrounding my house. Which is, you know, just that much more awesome.
It’s actually taken me so long to get over the trauma of that experience that I’m only writing about concrete now, even though our porches have been in since October. But here we are, fully recovered–with some quite beautiful porch caps, I might add– and it’s time to share some things everyone considering this decorative conglomerate should know before strapping on those concrete shoes and diving in.
Concrete: The Overview
First thing you should know, it’s called concrete. Not cement. From someone who spend 5 years of her life running a concrete block plant, let me tell you that if you call it cement, someone somewhere is laughing at you behind you back. (Cement is one of the things that goes in concrete. Calling concrete cement is like calling cake “flour”.)
Other things you should know:
- Concrete is made of cement, sand, aggregate (stone), water, and additives in varying amounts– the size and type of aggregate as well as the type of sand can affect color and finish. Light colors may also require white cement which is ridiculously expensive.
- How well concrete cures will affect the final product, things that can affect curing are: humidity, wind, temperature, moisture in the ground or area you’re pouring. (Even I had a minute of impatience where I was like, “Seriously?! It’s too windy to pour concrete? Is this a joke?” But it was not a joke. If the top of the concrete dries out faster than the rest of it, you’ll get all kinds of cracks on top. Trust me.)
- Concrete is fairly permanent, therefore you should not pick purple your colors on a whim.
Colors: This Ain’t Your Grandpa’s Concrete
The joke in that title is that my grandfather started the concrete company my family owned and operated for twenty years so technically for me it is my grandpa’s concrete, however let’s not start getting literal now.
The fact is, concrete technology as far as colors and stamping has exploded in the last couple of decades.
So you can have a plain gray concrete pad if that’s what you want, and frankly, that would make the decision process easier, but for the rest of us, here are some of the basics about concrete color:
- Concrete can be poured gray and then stained with a topical concrete stain
- Concrete can be painted or covered with an epoxy.
- Concrete can be colored with an “integral” color. This is a powder or liquid that is mixed into the concrete in the truck or mixer, before it is poured.
- Concrete can be colored with a “release”. Releases are used when stamping concrete to keep the stamp or form from sticking to the mud. Releases do not need to have a color.
- Concrete can (and should) be sealed with a top coat. There are varying finishes of top coat and it may or may not contain additives like an anti-slip sand.
You can use any combination of these techniques to achieve a custom look. (That’s what they say in the brochures, but I like to phrase it as “Getting the exact shit I want.”)
For our porches and garage floor we used an integral color with a colored release.
Stamping: Like Scrapbooking, But Bigger
So there are two ways to make concrete look like something other than a big square:
- Forms: These are the “walls” or the form that the concrete is poured into. For your standard square pad or porch they are made with 2x lumber (width depending on how thick your slab will be.) For a curved feature they make bendable concrete forms that can be staked with a radius– Something I plan to attempt in the next summer or two.
- Stamps: These are just what they sound like-large rubber stamps that are used to press a shape into the top of the concrete.
Some kind of release must be used with a form or stamp. A clear release, such as a form-oil, or a colored release that can come in powered or liquid form.
Tips For Picking Color
People, I almost had 500 square feet of purple porches surrounding my house so maybe you should take my advice with a grain of salt (or as my friend E says, a “grand assault”). Or just call this learning from my almost-mistakes.
There’s really just one tip here:
Don’t rush. See a sample of the exact combo you’re going to use before you decide on it.
Our problem was that nothing was just what we were looking for, so we tried a little last minute mix and match. The company we bought our color from did have actual concrete samples (you can’t pick this from a color brochure) and we spent many, many consecutive minutes staring at them. Over several days. Or weeks.
It’s all a little fuzzy now.
You can also ask companies if they have examples of jobs that have been installed in colors you like to drive by (easier if it’s a driveway, more likely to result in an arrest if you’re snooping around on someone’s back patio though).
And the other thing to keep in mind is that a sealer will change the color of the concrete drastically. That, my friends, was the magic solution in turning our purple concrete from this:
But it may not change the color for the better, so make sure you’re aware of what kind of sealer is used on the samples you’re choosing from.
Also speaking from experience: Neutral is better.
Here’s a quick look at the process in photograph form.
Forms with colored powder release:
Concrete with integral color:
Typical concrete finishing techniques were used to get it to a smooth finish:
The concrete was allowed to set up until the top was firm with just the slightest jiggle to it (probably 45 minutes to an hour in cool breezy conditions, and this completely depends on what your weather is).
Then the colored release was thrown across the top:
Which was a dirty, dirty job. Dust masks definitely required.
Then the stamps were used in alternating patterns while two guys did the “stamp dance” on them… it’s kind of like a shuffling square dance.
Then the sides of the forms were removed and stamped with a roller:
We were properly horrified at our very purple concrete at this point. And we stayed that way over night while the concrete set.
The next day, the release was artistically washed off with a power washer:
This is what gives it the variegated look. The less power washing, the more of the release color you see. The more power washing, the more base color you see.
Once the water has evaporated, the sealer can go on. For some colors this will just give you the darker “wet” look. For our plum release, it changed the color entirely… bringing us to a nice neutral grayish brown.
That could have been a disaster.
The concrete got two coats of sealer, and can be resealed as necessary when it starts to wear out. We put an anti-slip additive into the sealer, and word of caution, make sure you mix it well for the second coat because all the sand will have sunk to the bottom of the pail.
And those, folks, are the finer points of pretty mud.