And most abs toilet drain piping i ve seen is 4 not 3.
Toilet drain through floor joist.
That s only 4 over 16 feet.
While plain water will drain with.
Well you only need an inch of drop for every four feet for a pipe 2 1 2 or smaller.
Away from the top and bottom.
So your hole sizes will need to be a bit greater than that.
3 pipe is 3 1 2 od and 4 pipe is 4 5 od.
An important step in running drain lines occurs on paper before the actual plumbing begins.
So just measure carefully to maintain the minimum slope following the joist manufacturer s rules and you ll be fine.
Step 4 cut the holes.
Good luck with your project.
The slope should be about 1 4 for each foot of pipe.
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.
Area provided there are no other holes in the joist or notches along its top or bottom.
That gives you a 5 1 4 in.
Area in the middle of the 2 10 joist where the hole can go.
From the top and the bottom if it s a dimensional lumber joist.
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.
Running drainpipe through joists calls for meticulous work.
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.
Where and how to drill joists for electrical cables or plumbing runs depends on what type of floor framing you have.
And you can cut holes in the joists within the permitted range.
Do not even think to drill a hole for your toilet drain on your floor joist.
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.
Keep the hole at least 2 in.
Drill holes with a diameter of no more than one third the depth of the joist staying 2 in.
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.
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.
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.
A fall of 1 4 inch per lineal foot is the best slope for drainpipes.
