So I have an early 90’s home with 2 x 10, #2 Douglas Fir Floor Joists spaced 16 on center spanning 13.5 feet on either side of the main beam. The topsides are glued and nailed to the plywood sub-flooring above. The original owners decided to finish the basement. Great idea! They installed a drop ceiling and unfortunately, to make room for 2×4 drop-in light fixtures, they pushed a 1 inch heating line up into the floor joints by way of a 2″ x 2″ notch smack in the middle of each span. The floors do not appear to have moved at all over the past 30 or so years but I am now looking at installing granite counter tops and am thinking about the extra weight on the notched joists. I’m looking for any ideas to mechanically bring the 2×10’s back to their original strength. I really do not want to remove the ceiling to sister in new joists. Any help anyone can give will be greatly appreciated.. Thanks.