3 pipe is 3 1 2 od and 4 pipe is 4 5 od.
Toilet drain through floor joist.
Where and how to drill joists for electrical cables or plumbing runs depends on what type of floor framing you have.
How to install drain lines through the floor layout.
The holes must follow a straight line across the floor and must ascend or descend so the pipe will be sloped 1 4 inch per foot.
Away from the top and bottom.
So if you ve got a 2x10 you ll be able to squeak a piece of 4 pipe through if you carefully centre it in the joists from top to bottom.
And you can cut holes in the joists within the permitted range.
Step 4 cut the holes.
Well you only need an inch of drop for every four feet for a pipe 2 1 2 or smaller.
That s only 4 over 16 feet.
Area in the middle of the 2 10 joist where the hole can go.
The bigger hole you can drill on 2x10 it will be 1 inch and you need at least 4 try to build some how a bulk head downstairs if it is possible.
So just measure carefully to maintain the minimum slope following the joist manufacturer s rules and you ll be fine.
Area provided there are no other holes in the joist or notches along its top or bottom.
Mark the area of the tub footprint on the subfloor with crosses at each corner if it differs from that of the removed bathtub or if you are relocating the tub.
Mark where the overflow at the top.
Keep the hole at least 2 in.
If joists are 16 inches on center and pipes run across them at a right angle holes should differ in height by about 3 8 inch.
And most abs toilet drain piping i ve seen is 4 not 3.
Good luck with your project.
The slope should be about 1 4 for each foot of pipe.
Running drainpipe through joists calls for meticulous work.
From the top and the bottom if it s a dimensional lumber joist.
An important step in running drain lines occurs on paper before the actual plumbing begins.
Although notches aren t allowed in the center third of a joist s length you can drill holes anywhere along the length of the floor joist in that 5 1 4 in.
That gives you a 5 1 4 in.
A fall of 1 4 inch per lineal foot is the best slope for drainpipes.
The holes will have to follow a straight line that goes across the floor and has to either go up or go down so the pipe has a slope.
When you run your pipes through a joist you will have to be careful with your work.
Do not even think to drill a hole for your toilet drain on your floor joist.