Thanks for the thoughts I've gotten so far here, it's really helping me wrap my mind about the project.
Today's question is regarding drain slopes. I know that I'm supposed to have the drain pipes slope 1/4" for every foot. My question is "how do I ensure this?"
When I've worked with pvc piping before, the pipes set all the way into the fittings, and so they come straight out. I can bend the straight lengths somewhat, but on larger pipes it would be harder to do this.
In wandering around my cralwspace, most of the drain pipes didn't seem to be hung from straps or hooks or anything I'd normally picture would be involved. However, the straight lengths were somewhat short. Maybe that's enough that they could just be set at the right angle.
The only thing I can picture as a possibility is to control the slope using the veritcal pipes from the drains. If I cut them successively longer, that could force the slope. However, that feels pretty complicated if you don't know the entire geometry...
So, what is the standard/best installation technique for maintaining that critical slope?
The drain at some point turns, say at 90 degrees. Measure the space below the subfloor to the bottom of the 90.
Run the next pipe length and set the end at the proper drop. Support the middle at the proper height. If the run is 10 feet, the midpoint will be set 1 1/4" (5, 1/4's)below the drain 90. The end at 10, 1/4's(2 1/2" down from the drain 90.
Fill in any intermediate supports as necessary.
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."
B. Franklin 1759