Ok to cut or extend closet bend?

[peeks]

First my two questions, hopefully simple for the experienced to answer:

1) Does code allow the top of a 3"x4" closet bend be cut shorter?
2) Does code allow the use of an additional length of PVC to be cemented inbetween the closet flange and the closet bend - a sort of extension? If so, can it be 3" PVC?

As to why I need answers to these questions, here's the situation:

I am installing a new toilet in a new bathroom located within an unfinished space on the 2nd floor of a residence. The space underneath will also be finished at some point but right now it's unfinished. The drain for the toilet will be 3" PVC, and will run horizontally down the wall behind the toilet and tie into the main stack. The joists underneath the bathroom subfloor are 2"x10"s.

I'm having some trouble planning how to connect the toilet flange to the 3" drain... everything I've read says to use a fitting called a "closet bend". So I went out and purchased a 4"x3" reducing closet bend (as seen here:
The problem is this fixture, because of it's fixed height, may not work well in joining the drain to the flange. I guess I have 2 options here: 1) I can drill a hole and run 3" PVC through one of the floor joists and into the wall, or 2) I can make a soffit in the space beneath the bathroom and drop the drain below the floor joists to avoid having to drill large holes. If I choose the first option, the hole I drill in the joist will have to be dead in the center so as not to fail the framing inspection, so the closet bend will be too tall. - It will stick out WELL above the subfloor. On the other hand if I choose the second option, the closet bend will be too short. - The top of it will be located well below the subfloor.

So I'd like to know if a closet bend can be cut or extended to fit my installation.

Thanks in advance for any insight and advice!

 

[Terry]

The closet flange can be cut to fit.

First buy the 4" water closet flange and see where it will fit, that will give you some idea of where the cut would be.
I use the fitting pictured sometimes, and I always wind up cutting it down some.

Remember the vent.

 

[Sponsor]

 

[peeks]

Ok, thanks Terry - great info! What about the "extension"? - can I connect the flange to the closet bend with a length of PVC?

I guess I'm slightly afraid of drilling a 3.5" hole in a 2x10 joist to accomodate 3" PVC. The code states that you can only drill a hole 1/3 of the depth of the joist. So since the actual dimension of a 2x10 is 1.5 x 9.25, then 1/3 of 9.25 is just over 3 inches. But the diameter of 3" PVC is 3.5", so it doesn't seem like drilling a hole in the joist would be code-compliant.

I know this isn't a framing forum, but has anyone ever had problems with the inspectors after drilling such a hole? Or is this something that should never even be attempted?

 

[Terry]

You can extend with more pipe and a coupling if needed.

I put 3-9/16" holes in all the time.
You need to leave two inches on the bottom and two inches on the top.
You may want to check with your local inspector though.