I live in a 2 story house built in the 50's. We want to redo the bathroom in the upper floor. The pumbling is iron cast and runs underneat the joists, causing the ceiling in the lower floor to be shorter. We are going to replace the plumbing with 3'' pvc pipes. We want to make the ceiling in the first floor higher. Is it OK to drill 3'' holes in only 02 of the joists and 2'' in some of the others to reroute the new pvc pipes? Is there any kind of reinforcement metal plate for the joists?

From the Inrenational Residential Code 2003 Edition, Chapter 5 Floors, Section R502.8.1 Sawn Lumber:

"The diameter of holes bored or cut into members shall not exceed one-third the depth of the member. Holes shall not be closer than 2 inches to the top or bottom of the member, or to any other hole located in the member. Where the member is also notched, the hole shall not be closer than 2 inches to the notch."

The code makes no allowance for the use of any kind of reinforcing measure if the above limits are exceeded.