So, our home (15 years old) has a slab foundation with a crack running through it, and in the last few months we've been noticing cracks in drywall (jagged, and radiating outward from corners of window and door frames), doors sticking, and trim pieces separating from brick outside. Seems to be corresponding to a crack in the foundation running east-west.
We had 2 different reputable contractors out to take a look. Fortunately both came up with the same diagnosis, but they differed a bit in the scope and cost of repairs.
Contractor #1
7 piers (all external along southern edge of foundation)
Lifetime Transferable Warranty
Bid: $2650
Contractor #2
10 piers (8 external along southern edge; 2 breakout in garage)
w/ Lifetime Service Agreement: $5000 (1 future adjustment per pier)
w/ Lifetime Transferable Warranty: $6000 (unlimited future adjustments)
Am I oversimplifying by thinking of just going with the least expensive bid since it has a lifetime warranty? I think my hesitation in going that route is fear that in 5-10 years we will start seeing symptoms again and will need one or more of those additional piers that Contractor #2 would have included from the start.
Contractor 2 suggested watering the foundation (soaker hose every other day for 30-45 minutes)... said this would help prevent further movement, and may even shift things back to their original position and make foundation repairs unnecessary. I liked that he suggested something other than hiring his company as a possible solution... wasn't just out to get our money. However we've been watering it for about 3 weeks, but no noticeable change.