The closer to 2 inches, then you may think about doing something about it. I called a few foundation companies today. They charged $300-350 per pier.
Foundations leveling standards are determined on a case by case basis. In this case the home was evaluated and thereby concluded that a level cosmetic appearance and structural integrity would be the determining factors when performing the contracted workmanship. The owner further stated that if any foundation is corrected to its originally intended level surface that the foundation would raise but would create voids in various parts of the house, thereby causing sagging in the foundation and could create potential for further foundation failure.
This seems to make total sense! I hope everyone has learned something from this question! Can I get a thumbs up?
As to why these foundations are having soo many problems can be traced to a number of issues; but the latest probable cause that I couldn't believe I was hearing was how fast these contractors HURRY the curing process. A builder the other day, told me that he really adds some kind of chemical to the foundation so that it can cure in less than 2 weeks (on a 2400 sq. ft. single level slab) !! OUCH!! YIKES! I've been told... that "es no bueno"
IRC, 2000 Edition, Table R301.7 states allowable deformation of floors shall not exceed L/360. Although more detailed criteria may exist, this translates to 0.5â€ of allowable slope in 15â€™0â€ feet of horizontal distance.
So basically, less than 1/2 inch in 15 feet is generally considered not a much of a problem. I have heard the same said about 1 inch in 20 feet by other engineers. I have also had cases where slabs were not within either tolorance above, but where an engineer believed the condition was "as built" and not due to foundation movement., just questionable workmanship on the slab poor. For me, it all comes down to the level of accomplishement of the engineer and thier experience in a city. Both of these engineers use zip levels which if memory serves are supposed to be accurate to within a few tenths of an inch. Never heard of a water level. Third opinion? Good luck!