When we poured the concrete floors we decided to go with the rough look, big slab with expansion joints. I opted to leave the joints unfilled, because at the time I liked the look.
After 3 years I no longer like the look, and the joints made the floor difficult to walk on. I just had my first DEXA scan, I can't afford any broken bones. : ) But after being bombarded with those dual energy X-rays, I do feel more like Wonder Woman.
The joints also became the repository for dog hair, A LOT of dog hair. A Lab-mix dog sheds tons (I'm not kidding) in the desert.
A trip to Home Depot for backer rod and Sikaflex Self-Leveling Sealer and the project was on. The Sikaflex was easy to work with and though most likely chock full of petrochemicals with unpronuonceable names, it certainly did the job.
The only colors available were gray and sandstone, so I went with the sandstone. I was pretty sure some spray paint would take care of the color problem.
The Grand Canyon
Backer rod in place
Tape to protect the floor
Allowed to dry for 3-4 days and then paint
I used 3-4 different colors of RustOleum-my favorite paint, ever!
A couple of days of back-breaking, knee searing work but the hardest part was keeping the dog off it until it dried.
Well worth the effort.