Our house is 80 ft. long on a cement slab with concrete exterior. Ceiling joists run the length of the house. In our family room, we have a crack in the ceiling that my husband says will just keep reappearing no matter how many times he fixes it, due to the way the house is structured. Is there anything out there (material, practice) that can help us conquer this problem permanently? The room size is 22x24 with crack running the length of the 22 feet. Any suggestions would be helpful.

Without knowing anything about the structural issue that causes the crack, and without knowing the direction of the crack relative to the ceiling joists, there isn't much that can be offered.

Can you get into attic above the ceiling, or is it finished above?

If you can you need to check if there is another built up beam running at a 90 degree angle to the ceiling joists in which they are butted to. Quite often this is where the issue of ceiling cracks develop.

What happens is the weight of the roof, during winter with snow loads, will cause the outside edges of the roof along the gutter to push out.Not a lot, but enough to open up the crack. When this happens the ceiling joists pull away from the beam that they are nailed to.

The easy way to prevent this would be to remove any flooring that is above this area and put down a sheet of plywood that will span over the center beam and onto both sides of the ceiling joists. Be sure to use liquid nails on every joist and center beam and then nail or better yet screw each joist on 6 inch centers. What this will do is prevent the wood from moving apart the next time there is a snow load on the roof. That should stop the cracks from occuring again.

Is the crack developing between what would be room openings? That would be the reason. They simply do not span across from the front all the way to the back of the house.