I am “Garage Guy”. I want things to be just so. Everything in its place, neat and tidy. Clutter I can control, the concrete someone placed in 1975 I can not. They used a 2×4 for the joint and while done well, it was about 3/8 of an inch in some places lower than the slabs. This made for a sweeping issue as well as a collection point for water and winter melt off debris.
I have used the Sika product shown here before. I just never thought of sharing it with you till now. I have used this multiple times for my customers, all with great results. So when I finally had enough with my floor, it was down to Home Depot and I bought a case of this Self Leveling Sealant. The case of 12 cost me $96.24 after tax. Not cheap, but the results were worth it. I must also say, that I used a BUNCH of this stuff. Probably to the point of over kill. Hopefully you will not need as much.
I started by cleaning out the gap and plugging any visible spots where I could see it would fall in further than I wanted. I also dammed up one of the ends where it would run out if not stopped. The Gray Sikaflex SL is runny so that it will level itself. It is also designed for horizontal surfaces. My garage floor had a bit of a slope from the back to the garage doors and this was not a problem for the product. However, I can see that with just a bit more slope, it could have all rand down to the end. If in doubt, build it up in a couple of thinner layers. Also, if any soaks in or dips, let it firm up, and just add more on top.
You can see by the photos, parts were about 1 ¾” wide. I also kit a few cracks. Shown for reference is a section that I did about two years ago where the concrete joined an asphalt drive. While not specifically recommended for this, it has held up well. See all the dirt and change of color? Get ready for this as the finished product does attract whatever blows by or runs over it. I could care less about the final color, what was important is that I can now keep out the water and chunks and my slabs will last longer.
The product takes a while to cure so make plans to not walk on it or drive on it for up to 3 days depending on how deep or wide you apply it. Again, I took it to an extreme.
Summary? Good stuff. Works well. Does what it is supposed to. Lasts and is of value. Cautionary advice? Go slow. Practice, don’t overdo it till you see how it is to work with. Also, do it on a warm day. Not hot or cold. And have a good caulk gun. A smooth, comfortable caulk gun. Junk guns make for junk results.
All the technical info if you need it.