Tub Drain Repair

One of the things we did while Mandy was here was to repair the tub drain. For the purpose of explaining the anotomy of a tub drain, I will share with you my finished work first. 1) 4"x4" Castiron to Plastic Coupling (sometimes referred to as an "adapter") This is what allowed me to mate up the new PVC pipe to the old cast iron drain system. 2) The Trap Arm is what carries the waste water to larger drain pipe called the stack vent. Trap arms can only be so long. If the trap arm is too long, it can cause the waste water to back up. 3) The P-Trap always has some water collected in the bottom. This water creates a seal that prevents fumes from the sewer/septic from venting into your bathroom. 4) 4" to 3/4" adapter allows the drain pipe on the tub to mate up to P-Trap. 5)Tub drain pipe and 6)overflow drain pipe have adjustable lengths so it will have a universal fit. The Face that mates to the tube uses a rubber gasket as its seal.

When Angela and I moved in, we knew the tub was missing the trap arm and P-trap but we put off repairing it because it involved getting under the house in the dark with all the creepy crawlies. Someone in the past started to repair the tub drain and never finished. They left me about 8" of 4" pipe and removed everything else to the tub with the exception of the tub's drain pipe.

First I dry fit the 4"-3/4" adapter and p-trap together. That allowed me to get a measurement for the new section of 4" pvc pipe i was going to need for the trap arm. I called out the measurments to Angela who used a pvc hand daw to make the cut. then I dry fit everything. The cast iron to pvc coupling was very easy to use. It is just a rubber sleeve that slides over the joint between the two pipes and then you tighten the two metal bands. Make sure that the one band is over the metal pipe and the other is over the pvc pipe. With the coupling in place and secured I disasembled the p-trap and glued it with some pvc glue. I like using the Rain-R-Shine because sometime (true in this case) the stuff you are working on is wet. I kept the collars on the tub drain close so I could assemble the parts together easily. After the pvc cement started to set up, I tightened the collars on the tub drain and overflow drain. and I was done. Below I will post some of the pictures of the condition of the plumbing in the bathroom

With a panel removed from the hallway wall, you can see the original plumbing that supplies the tub.

This is me doing the final assembly.

Here is a handy table that shows the trap length allowed for several diameters of pipe and the slope the trap has to be at to work properly.