Concrete Stains vs. Concrete Dyes & How Concrete Hardness & Polish Affect Color
How do you know what will work best, stain or dye? The hardness, porosity, grind level, and final finish of the slab can make a pretty big difference in what type of stain or dye will work and how well it will penetrate to give you the desired look you are going for.
Stains vs. Dyes
The easiest way to explain the difference is:
Concrete stains tend to create a more natural, mottled, stone like appearance.
Depending on the type of stain, it either chemically reacts with the concrete or deposits larger pigment particles into the pores of the surface. This gives you a lot of those natural variations people like with decorative concrete, acid staining, and similar flooring applications.
Concrete dyes are more about strong, controlled color.
Dyes use much smaller color particles that are carried into the concrete using something like water, acetone, denatured alcohol, or a specialty carrier. Because the particles are so small, dyes can penetrate much deeper and give you much more vibrant and consistent colors.
This is one reason dyes are so popular for interior polished concrete, decorative flooring, commercial flooring, and custom floor graphics/designs.
In general, stains are a great option when you're looking for a more natural finish, especially for exterior concrete, while dyes are great when you want richer colors, more color control, and custom flooring designs.
But Concrete Hardness Matters
This is where things start getting interesting!
Concrete hardness is generally talked about in terms of PSI (pounds per square inch).
As a very general guideline:
Soft concrete: around 3,000 PSI or less
Hard concrete: around 6,000–8,000 PSI or higher
Obviously there is a lot of concrete in between those numbers, and PSI isn't the only thing that determines how a finished floor will accept color.
The important part is that harder, denser concrete generally has less porosity, which means it can be harder for a dye or other coloring product to penetrate.
Soft concrete is usually more porous and will accept color much easier.
Soft Concrete
With softer concrete, dyes can usually be applied around the 200-grit stage.
Acetone-based dyes are commonly used here because acetone flashes off quickly and can carry the dye into the pores of the concrete.
This can make application pretty quick and forgiving when you're working on a floor that is accepting the product well.
Hard Concrete
Hard concrete is a different story.
You may need to take the floor closer to 400 grit before applying a dye.
At this point, acetone may not penetrate the concrete well enough, especially on a very dense slab. This is where a different carrier can become useful, such as:
Denatured alcohol
Ameripolish Color Solve
The basic idea is that you need to match the coloring product and carrier to the actual concrete surface, rather than just assuming the same dye and application method will work on every floor.
How Does the Grind/Polish Level Affect It?
This is another big one!
Below 100 grit (50–80 grit pads)
This is more common with rougher surfaces, outdoor concrete, warehouse floors, or concrete that still has a fairly aggressive surface profile.
The more open surface can accept penetrating products more easily, but the rougher surface can also create other issues.
For example, when installing flooring graphics or other materials over these surfaces, a High Tack material may be necessary to get proper adhesion and help prevent bleed-through. Low Tack material may not hold as well on a rough surface.
Water is commonly used as a penetrating agent on these types of surfaces, although acetone may sometimes be used depending on the coloring product.
If you're quoting a job with a rough or unfinished floor, it is definitely worth finding out exactly what the concrete looks like and what coloring system is being used before deciding what material/application method will work.
Around 200 Grit
This is where a lot of decorative concrete coloring happens!
Around 200 grit is commonly a good stage for applying concrete dyes to soft-to-medium hardness concrete.
Acetone-based dyes are often used because they flash dry quickly and can penetrate into the concrete before evaporating.
This can be a good stage if you're trying to get color into the slab without polishing the surface so heavily that you close it up.
Around 400 Grit
400 grit is often one of the last more aggressive grinding stages before the process starts becoming more about increasing the shine and refining the finish.
A lot of contractors will stop around this point for a dye-and-seal process:
Grind → Apply Color → Seal
On concrete that is still accepting water at this stage, acetone may still work depending on the product and slab. A simple water test can help determine how open the surface still is.
For harder concrete, 400 grit can be a better stage for applying dye because the surface is still open enough to accept color, but the floor is already getting a much more refined appearance.
If the concrete is too dense for acetone to penetrate, a carrier such as denatured alcohol or Color Solve may be needed.
800 Grit and Higher
This is where penetration gets much more difficult...
You can still apply concrete dyes at higher polish levels, even up to around 1600 grit, but you need to use the appropriate carrier. Color Solve is one example used for this type of application.
Once the concrete gets this dense and polished, water generally isn't going to be a good penetrating agent.
If the correct carrier can't be used, you may need to reopen the concrete surface.
That could mean grinding back down to a more open surface or using a light profiling method, such as a profiling gel.
One example is Surface Gel Tek's Gel Profilers.
And there is another thing to watch out for when grinding back down:
You may expose more aggregate.
Once you're working with exposed aggregate, dye isn't going to color everything the same way. Some aggregates are essentially glass-like and won't accept the dye the way the cement paste does.
So you can end up with a completely different look than you expected.
The Short Version
There isn't really a universal “best concrete dye” or “best concrete stain.”
The right product depends on:
Concrete hardness/PSI
Porosity
Existing surface condition
Grind level
Polish level
Type of stain or dye
Carrier being used
Interior vs. exterior application
Desired color and finish
Whether the floor will be sealed afterward
For DIY concrete flooring, home improvement projects, commercial flooring, decorative concrete, polished concrete, or construction projects, I think understanding the surface you're working with is just as important as choosing the color.
A dye that works beautifully on a 200-grit, soft concrete floor may behave completely differently on a hard, highly polished 800–1600 grit floor.
I'd be really interested to hear what other contractors are seeing in the field. Do you have a preferred grit for applying dyes? Do you use acetone, alcohol, Color Solve, or something completely different?
And if any of this is off based on your experience, definitely let me know. We're putting together a larger concrete flooring/coloring FAQ, so real-world contractor feedback would be extremely helpful.