Supporting floor joists with 3" holes

[BarrEb]

Hello,

I have a question regarding how to properly support floor joists in order to run a 3" drain line through them.

The project is a bathroom renovation and unfortunately the 3" drain line from the toilet will need to run through 4 floor joists. I know this isn't ideal, but unfortunately there is no other way to run the pipes. The floor joists are 2 x 7-1/8 and spaced 16" on center. Attached is an image of the flooring. The blue line shows where the 3" line needs to run.

I know 3" holes in 7" joists is no good, but is it OK if I reinforce the joists with steel. My thought was to use 4 steel support members on each joist that are 12" x 1.5" by 3/32" thick and installed as shown in the second attached image.

What do you think about this approach? Is there a better way that I should be reinforcing these joists?

Thanks!

Bill

 

[Doghouse Riley]

Personally, I'd use some angle iron from an old bed frame if I could find one.

My son and I used the same material to make a frame to support a chimney when we took the chimney breast down in a bedroom to make the room bigger when we split it to form a bathroom. It cost us nothing. That was twenty-odd years ago.

If not you could probably buy some lengths of Dexion shelving or similar. It's extremely rigid.