How to Replace Cast Iron Pipes

Cast iron pipes and fittings

Rate: (0 Ratings)

While cast iron pipe is typically not installed in homes these days, years ago it was frequently used in DWV systems and there are still many houses with cast iron pipes installed. In the event that you have to replace your cast iron pipes, read on to learn how to effectively approach this project.

Flag Article

Instructions

Difficulty: Moderate

Things You’ll Need:

Chalk
Adjustable wrench
Cast iron snap cutter
Hacksaw
Ratchet
Wrench
Riser clamps or strap hangers
Wood blocks
Wall board screws 2 1/2 inch
Banded couplings
Plastic pipe

Replacing a Section of Cast Iron Pipe

Step1

Use chalk to mark cutting lines on the cast iron pipe. If you are replacing a leaky hubbed fitting, mark at least 6 inches above and below the fitting.

Step2

Hold up the lower portion of pipe by installing a riser clamp tight against the bottom plate or floor. Install a riser clamp 6 to 12 inches above the part being replaced. Attach wood blocks to the studs with 2 ½ inch wallboard screws, so that the rise clamp rests securely on the tops of the blocks.

Step3

Cut the cast iron pipe using a snap cutter or a reciprocating saw with a long metal-cutting blade. When using a snap cutter wrap the chain around the pipe so the cutting wheels align with the chalk line you drew. Tighten the chain and then snap the pipe according to the tool manufacturer’s directions.

Step4

Make a second cut at the other chalk line and remove the section of pipe. Cut a length of PVC plastic pipe 1 inch shorter than the section of cast iron pipe that has been cut away.

Step5

Slip a band and neoprene sleeve of a banded coupling onto each end of the cast iron pipe. Make sure the cast iron pipe is seated snugly against the rubber separator ring molded into the interior of the sleeve.

Step6

Fold back the end of each neoprene sleeve until the molded separator ring on the inside of the sleeve is visible. Position the new plastic pipe so it is aligned with the cast iron pipes.

Step7

Roll the ends of the neoprene sleeves over the new plastic pipe.

Step8

Slide the bands over the neoprene sleeves and tighten the screw clamps with a ratchet wrench or screwdriver.

Tips & Warnings

Cast iron pipe is heavy, and you must provide permanent support on both sides of a pipe before cutting it.
Support vertical cast iron pipes at every floor level and above every cut you make, using riser clamps.
Wear eye protection when cutting cast iron pipe, and if working in enclosed basement or other space, wear ear protection too.