Color matching stucco can be difficult, even when you have a clean sample, as there are other aspects that can make matching it harder. Matching a stucco color that is faded, discolored or stained can be even harder because the true color can be hard to determine.
Color Matching Stucco (In General)
I have a fairly detailed article on how to match your stucco's color, but I did not go into a huge amount of detail on stucco walls that have staining or discoloration in them.
Pulling A Sample: The best thing you can do would be to pull a small sample from somewhere on your home or building, from an area that is less noticeable (like under a deck or on a back wall) and then patch that area later. This could be harder on discolored walls, as there may not be a clean enough area anywhere on your walls to get a decent sample.
If you do happen to get a good sample, you can then take that in to a stucco manufacturer and have it matched. If you are planning on painting the stucco, then taking the sample in to have a paint supplier match it is the other option.
No Sample: If you can't (or don't want to) pull a sample from somewhere on your house, then the process is going to get quite a bit more difficult. You would then have to get a couple of different color charts (stucco or paint) and hold them up to your wall to see if there is a close match. This is not recommended unless you know what you are doing and specialize in custom stucco color matching.
Alternative Option: You could also just change the color of the walls, which would be easier to do but cost a lot more, obviously. I just wanted to throw that out there for those of you that might have a hard time getting a match.
Faded, Discolored & Stained Walls:
Knowing what we now know, we can see that getting a color match for walls that have stains, discoloration or fading is even more challenging, but there is still hope! Below is a very extreme example of all three problems occurring on one large wall.
Even though the example wall has a lot of color issues (along with other issues) there is still an area off to the left that has more of the original stucco color, which was a light yellowish color, done in a two coat, Santa Barbara (cement based) type of finish.
For reference, this stucco was 21 years old and even though the wall on the left is closer to the original color, it is still likely faded and softer in tone than when it was new. If I were to grab a sample, it would be from somewhere in that area.
Helpful Tip: A good tip for stucco that has color issues would be to do a light pressure washing on the finish to try and clean up some of the staining and discoloration issues.
Finding A Better Color Sample Area:
I have been to many, many different stucco houses with these types of issues and I have been able to walk around the house and find one wall or an area on one wall that was much cleaner that I could either grab a sample from or hold a color chart up to try and match the existing color.
In the above image, you can see the wall that was in really bad shape, off in the corner to the left, but this wall was only around the corner and was in much better shape, as far as the stucco color goes. This would be an ideal wall to try to match the existing color on.
Holding A Color Chart Up To The Wall...
If you can't get a sample or just have so many areas where the color is not clean, then holding up a color chart to the walls is another option you have. Keep in mind, that this is a lot more difficult to match the color of stucco walls with, but is possible, if patient and willing to experiment a little.
You may have to try 3 or more samples if your color is close to a few, in order to get the closest possible match. You will then have to apply your samples to the wall and see how well it matches. Once you get a color that is close, you may have to lighten it (adding more base material) or darken it (adding more pigment) to match the existing finishes color.
