This is a popular topic of discussion with customers. We get alot of calls and emails from customers asking about coloring techniques for broom finish "plain" concrete vs stamped concrete. We have some other articles that discuss this topic, but this BLOG post will hit the topic from a slightly different angle.
Other articles discuss the options to color stamped concrete, ie the differences between surface color hardener and integral "through-and-though" color.
This post is more about broom finish concrete. Broom finish concrete or "brushed" concrete, is plain, regular concrete. Most all sidewalks, for example, are made with basic broom finish concrete. This is plain concrete, placed and finished with standard techniques. Just as the concrete is starting to dry, typically same day it was poured, the workers draw a broom through the concrete to create the broom finish. This technique has been around for dozens of years, probably more.
The basic reason for broom finish is for traction. The broom lines are typically applied cross-wise from the direction of foot traffic or car path for a driveway, so that the broom lines create traction.
So what color is regular broom finish concrete you might be asking? Well, there is typically not any color added, so the final color is the sum of the color of the ingredients. Now-a-days, that equals white. Yes, white, very white. Now as a reminder, the first week or two, the concrete will be dark and somewhat discolored, but once is cures within a month or so, it will blend to a rather stark white color.
Another option for those customers that want basic broom finish concrete is to add color to the mix. So when we order your concrete from the production plant, we would order it pre-colored with whatever color you'd like. There are 50+ colors to pick from off of a color chart. The price to add color usually reasonably inexpensive for lighter colors, then gets more expensive for medium range and rather expensive for the darker colors.
For example, the color can cost $1 - $2 per square foot for the lighter colors and $4/sf for darker colors, graphite, dark brown, brick red, etc.... So you know, the cost of adding color to the concrete also covers the minimum charges from the production plant. For example, most colored concrete must be ordered with a minimum of 3 cubic yards ... this restriction often changed the number of yards, ie the quantity we order for your job. So the price we charge to add color to broom finish concrete, isn't usually just for the color, but also for some other things including the need to often order more concrete than you might really need.
Broom finish concrete would always be colored with integral "through-and-though" color and never colored with surface color hardener. Most always, surface color hardener is reserved for stamped concrete only.
Broom finish concrete can also show discoloration during the curing process, and the discoloration can be permanent. This isn't just YOUR concrete, but for all broom finish concrete. Next time you are walking into a school, or office building, or into the mall, and you are walking across a large concrete plaza area to get into the building, look down ... look at discoloration in concrete. Most all concrete slabs / areas have sections with discoloration, but most often people don't notice, honestly, because they simply aren't looking at it. Customers do, however look much more closely, and are thus much more critical, when that concrete is their own new driveway, walkway, etc.... Discoloration isn't normally because the contractor did a bad job, it's just part of how concrete works / cures ... this is why we always do our best to education, ie warn broom finish customers of these issues ... and to not be surprised or upset when your concrete has some discoloration.
Hope this clears up some coloring issues for you. We want you to be very excited about your new concrete slab!!
Salzano Custom Concrete
Plain broom finish concrete sidewalk, no color, regular white concrete, somewhere in southern virginia (I think), probably a year or two old, with some amount of discoloration. Would you have noticed this if we didn't point it out? Would you have noticed it if this was a new walkway in front of your house?
(right side) is broom finish concrete with color pre-mixed .. this color is called "Sandstone".