looked at a job today where the homeowner wants to add a toilet upstairs. The best route would require drilling through 1 or 2 ceiling joists that are 9" wide.

so by the code max hole size would be 3" (1/3 of width) and the 3 1/2 hole I need to run 3" ABS is too big and a code violation.

Anyway structural way around this if an carpenter came in and added material?

I'm thinking the drain will have to run parallel to the joists and come down a different wall or below the joists in the ceiling below.

any input is always appreciated. thanks.



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Plywood can be glued and screwed to the side of the joist(s) to strengthen them. How long are the joists ? On 16" centers ?

I generally try to get the homeowner to go with a soffit, makes your life much easier and in many cases it can accentuate a room because lighting can be placed in there also. Most are open to the idea from my experience since it is going to cost them less in the long run.

PlumbCat TM 2003


Plumbermandan

how far from the end will the holes be?
if you are within 2-3 feet from the end, i forget which, they want the joist notched rather than drilled in the center.. something about stress vs compression..

Another option that the plumbing code talks about is the use of metal stud shoes. Sometimes the building inspector will allow these to be used if the hole size exceeds one third of the total joist depth.

The ideal would be to put it between the joists and then drop down in a wall, an alternative would be to header off the joists to create a "box" for the piping.

all good solutions. thanks so much.