How to Mix PVC & Cast Iron Fittings on a Bathroom Installation

PVC pipe can be mixed with cast iron in bathrooms with the right coupling.

Old homes might still have cast-iron plumbing, but this material is no longer used for pipes and fixtures. You don't have to remove all of the cast iron in your home, however, during installation or repair work. Use rubber compression-clamp couplings to tie modern PVC pipe into an existing cast-iron pipe. Also, the two pipes do not have to be the same diameter to use a coupling.

Things You'll Need

• Measuring tape
• Rubber compression-clamp coupling

Instructions

1. Measure the opening for the cast-iron pipe in inches.

2. Measure the PVC pipe fitting opening in inches.

3. Select a rubber compression-clamp coupling to match the diameter on one side for the cast-iron fitting and to match the PVC on the opposite end.

4. Loosen the clamp bands around the coupling.

5. Slide the PVC end of the coupling over the PVC pipe.

6. Insert the cast-iron fitting into the opposite end of the rubber compression coupling.

7. Push the PVC pipe toward the cast-iron fitting inside the coupling until the two touch.

8. Tighten the compression-clamp bands around the rubber coupling.

Tips & Warnings

• Look for rubber compression-clamp couplings in various sizes at home-improvement stores or plumbing-supply stores.

• Always shut the water to the house off before beginning any plumbing work.

References

• Creative Homeowner's Ultimate Guide to Home Repair and Improvement: 325 Step-By-Step Projects 3,300 Photos and Illustration; Creative Homeowner
• Plumbing a House; Peter Hemp