I have a concrete patio that consists of 4 sections, about 10 feet square each, and they are slightly shifting to create 1/2" spaces between them, and the house foundation too. (you can't see how far down the crack goes. seems deep) I had a tuckpointer here, and he mentioned that besides the work I originally called him about, he could fix this as well. As you can imagine, constant rainfall and freezing weather washes away dirt under the slabs, so over time I'm afraid this will get worse. The house (and maybe the slabs) are about 50 years old, and we live in the Midwest over clay soil. There is other evidence of shifting soil around here.
The tuckpointer said he'd use hot tar to seal things up in between the spaces. I wonder if that's a reasonable fix, or if I could use another material, perhaps even myself, to get a good result. Would silicon work in this situation? Other sealants?