Upgrade Your Bathroom: How To Put A Pvc Toilet Flange On Cast Iron Pipe

When replacing or installing a toilet, you may encounter a situation where you need to connect a PVC toilet flange to a cast iron pipe. While this is possible, it requires careful preparation and the right materials to ensure a secure and leak-proof connection. In this blog post, we will delve into the details of whether you can put a PVC toilet flange on a cast iron pipe, the necessary steps involved, and the potential challenges you may face.

Compatibility Considerations

The compatibility between PVC and cast iron is a crucial factor to consider. PVC (polyvinyl chloride) is a lightweight and durable plastic material, while cast iron is a heavy and rigid metal. Due to their different properties, direct connection between the two materials can be challenging.

Required Materials

To successfully connect a PVC toilet flange to a cast iron pipe, you will need the following materials:

• PVC toilet flange
• Cast iron to PVC adapter
• Pipe dope or thread sealant
• Hacksaw or pipe cutter
• Sandpaper or emery cloth
• Measuring tape or ruler
• Level

Step-by-Step Instructions

1. Prepare the Cast Iron Pipe

• Use a hacksaw or pipe cutter to cut the cast iron pipe at the desired location for the toilet flange.
• Deburr the cut edge of the pipe using sandpaper or emery cloth to remove any sharp edges.

2. Install the Cast Iron to PVC Adapter

• Apply pipe dope or thread sealant to the male end of the cast iron to PVC adapter.
• Screw the adapter into the female end of the cast iron pipe by hand until it is snug.
• Use a wrench to further tighten the connection, but avoid overtightening.

3. Measure and Position the PVC Toilet Flange

• Measure the distance from the finished floor to the top of the cast iron pipe.
• Subtract the thickness of the PVC toilet flange (usually 1/4 inch) from the measurement.
• Mark the position of the flange on the cast iron to PVC adapter using a pencil or marker.

4. Install the PVC Toilet Flange

• Apply a bead of pipe dope or thread sealant around the bottom edge of the PVC toilet flange.
• Place the flange over the cast iron to PVC adapter and align it with the marked position.
• Tighten the bolts that secure the flange to the adapter using a screwdriver or wrench.
• Check the level of the flange to ensure it is level in both directions.

5. Seal the Connection

• Apply a generous amount of silicone caulk around the base of the PVC toilet flange where it meets the adapter and the floor.
• Smooth out the caulk using your finger or a putty knife.

Challenges and Troubleshooting

• Improper Fit: If the cast iron to PVC adapter is not properly fitted, it can cause leaks or damage to the connection.
• Uneven Surface: The cast iron pipe may not be perfectly level or smooth, which can make it difficult to achieve a secure seal between the flange and the adapter.
• Corrosion: Cast iron pipes can corrode over time, which can weaken the connection between the flange and the adapter.

Alternatives to PVC Flanges

If you encounter significant challenges in connecting a PVC toilet flange to a cast iron pipe, you can consider alternative options:

• Wax Ring: A wax ring can be used to seal the connection between a toilet base and a cast iron pipe without the need for a flange.
• Flange Repair Kit: A flange repair kit can be used to repair or replace a damaged flange on a cast iron pipe.
• Cast Iron Toilet Flange: You can purchase a cast iron toilet flange that is specifically designed to fit cast iron pipes.

Recommendations

Connecting a PVC toilet flange to a cast iron pipe is possible with the right materials and careful preparation. By following the steps outlined in this guide, you can ensure a secure and leak-proof connection. If you encounter any challenges or have concerns, do not hesitate to consult with a qualified plumber for assistance.

Questions We Hear a Lot

Q: Can I use a regular PVC flange on a cast iron pipe?
A: No, you need a cast iron to PVC adapter to connect a PVC flange to a cast iron pipe.

Q: How do I know if the flange is level?
A: Use a level to check the flange in both directions to ensure it is level.

Q: Can I use silicone caulk to seal the connection instead of pipe dope?
A: It is not recommended to use silicone caulk as a substitute for pipe dope or thread sealant.