Altering a floor joist

I plan on spending some of my time to repaint the bathroom and put down some new flooring but before that I want to deal with a problem I have always had here.

The problem is my toilet is too far away from the wall and is crooked!

I found out the reason for this is there is a floor joist right in the way where the drain should come up from the floor.

I have never had to deal with this type of issue before. What I was thinking was cutting the joist and make a box where the drain should run. I will use joist hangers to secure the sides of the box to the adjacent joists and then nail the box into the ends of the joist I cut.

Any ideas on this?


David please provide a picture.
Come on man you should know that by now.

Haha Bob I really wanted to do that too! However I dont really want to crawl way back in the crawlspace to do it heh.

Ill try to make something up gimme a few.


How you modify that floor joist will depend on where the cut is in relation to the joist span and the loads on the floor in the area where you need to cut.

Is the wall behind the toilet a load bearing wall?

What is the span, size and spacing of your floor joists?

Is you roof system engineered trusses or stick built?

Also would need to see a floor plan sketch of the walls including the location of the main beam your floor joists are supported by in the crawlspace. In the attached photo probably your worst case loading will require Modification #1 using metal hanger straps for the connections.


If you are not an engineer…and you plan to, someday, sell the house…you would probably not want to alter the floor joist.

If you do, be prepared to address it to the satisfaction of a future homebuyer who will likely be advised by their home inspector to consult with a structural engineer.

Not on a load bearing wall, the joists are 2x12s on 16 in centers and the trusses are engineered.

Here’s how I would handle it as an AHJ if done by a contractor under a permit.

Pardon me for stating the obvious, but have you considered a toilet offset flange rather than cutting into your house?

Michael I will have to look into that! I didnt think to go that route thanks!
I am not sure if it will work but I its worth doing some looking into thats for sure!

It is not a compacted affair. UNLESS.
I am assuming that it is typical farming. A.S.S/U/ME
You are right in providing prudence as a precaution…