I have this 1968 sun/screen room and I removed the indoor / outdoor carpeting, actually 3 layers of indoor outdoor one kind on top of another (from previous owner). After doing such thinking "lets see what slab looks like" for the most part it is in very good shape. I dont believe its more than 4 inches thick. That being said it has a crack across the entire width of concrete aprox 3/16 wide. What do you recommend to repair this long aprox 15' long and as i said about 3/16 wide of a crack.
Why do you feel it needs to be "fixed"?
It's a normal settling crack.
It could be cut out and filled but it will stick out and may not last if the slab moves some more.
What type flooring are you going over it with?