You probably don't want to fill the expansion joints. They are there for a reason: expansion. If you fill the joints you risk the material being squeezed out in the future - like dried up toothpaste. There are flexible metal products that can be added. But again those are normally specified before the floor is finished.

The other thing the joints are there for: cracks. They "make" the concrete "crack" where you want them to crack. They reduce the large splits/cracks that come with concrete floors. If you fill them, you set yourself up for a concrete slab that will create new cracks - cracks where you didn't want them to be.

Can you add photos?

Is that exterior flooring - like a patio? Everything is exposed to the sky. Or is this the slab pour and you are about to finish the house later?

If this is the slab and the house is about to be built over top, you will want to wait to figure out how to deal with this. You have months and months and months to figure this out.

And what does your professional concrete floor finisher have to say?

Disaster in the making. You need to hire someone with a clue. You've already gone down the wrong path, and it may not ever be fixable. Certainly not ''on a budget''.

The concrete guy knew this was to be a finished concrete floor from the start. My parents have a finished concrete floor (stamped and stained), as well as other friends of mine. If finished concrete floors aren't a thing, why do they have colored mix to.mix int he Crete?

I'll hold off on filling the expansion cuts. There's lots of products designed for filling them (sikaflex being one) my issue is we dyed the concrete charcoal and I can't find anything polyurea filler between "black" and "limestone".

I'll also hold off on applying the sealer (bellatrix) till after we frame. My concrete guy said to seal it seven days after the pour. It's been 16-18 or so. I figured it'd be easier to do before the walls go up and also offer a little protection during the build. I'll take your advice and hold off.

So, what we did was used a higher psi (4200 I believe) concrete mixed with charcoal coloring. Poured it out, they "burnt" the floor with their machines (I forget the correct term, forgive me) then he wet cut the expansion.lines. I guess I don't understand what the issue is with sealing this with a quality sealer and using it as my floor.until I can afford to hardwood etc.

Thanks for your insight, I appreciate the constructive feedback. I'm hear to learn. Don't take my replies as argumentative, just trying to explain my current process.

I don't think my concrete guy was the best. Obviously. That being said, I don't really have many other options.

Hi! I noticed this thread is 6 years old... haha, but wondered if you might still get this message. Did you ever find a product that you were happy with to fill the concrete joints? We have an interior concrete floor (radiant) and still searching for the right caulk to use inside. I hope you're happy with how your project turned out!:) Thanks!