Why is there a hump in my floor?

Why is there a hump in my floor?

There is a definite hump in the floor that is normally found in older homes. In older homes the foundation sinks leaving the center of the house higher. But this is a different problem.

Let’s say your house was built in 1985.Builders were combining engineered lumber with conventional lumber. Engineered lumber doesn’t shrink like conventional lumber. If you start with a 2 x 9.5 inch LVL (laminated veneer lumber) beam, 20 years later it’s still a 2 x 9.5” beam. However if you start with a standard 2×10 (which is really only 1.5” x 9.5”), 20 years from now it shrinks to 1.5” x 9.25”. So now your floors are all ¼” less than the height of the beam. The plywood that is nailed to the floor and stretches across the beam will now be humped up over the beam.

The solution is to remove the plywood directly over the beam and fill that area in with floor leveler or a thinner piece of plywood. Problem solved.