How to join cast-iron soil pipe

Updated February 21, 2017

Cast-iron soil pipe is used in some sanitary sewer and storm sewer below-grade installations. The pipes are also used for interior fittings at the main soil stack or central point of the sewer connection within the home. There are two methods of joining cast-iron soil pipes.

Clean any dirt or other foreign material from the ends of the two pipes to be joined. Insert the rubber gasket within the hub to the point the lip of the gasket rests against the end of the hub. This commonly requires folding the gasket and inserting it within the hub before allowing it to unfold with the lip at the top edge of the hub and the rib of the gasket fitting within the groove near the end of the hub.

Lubricate the spigot end, the small end of the fitting or pipe, with the product recommended by the pipe manufacturer.

Slide the spigot end of the pipe into the gasket of the hub. Use a lead maul or hammer to force the spigot end of the cast-iron soil pipe into the gasket and hub. The lead of the maul is soft enough not to damage the cast-iron pipe.

Slide the rubber gasket over the end of the piece of pipe until the inner ridge of the gasket touches the end of the pipe. Place the clamp over the other segment of pipe of fitting that is being joined to the original pipe.

Place the second pipe into the rubber gasket, forcing it against the centre segment of the gasket. Slide the clamp over the gasket, and centre it over the point where the two pipe segments connect.

Tighten the clamp to 60 in/lb using a torque wrench. Larger pipes may have multiple clamps to tighten into place following the same procedure.

Things You'll Need

  • Cast-iron soil pipe gasket
  • Clamp
  • Lead maul
  • Torque wrench
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About the Author

Keith Allen, a 1979 graduate of Valley City State College, has worked at a variety of jobs including computer operator, medical clinic manager, radio talk show host and potato sorter. For over five years he has worked as a newspaper reporter and historic researcher. His works have appeared in regional newspapers in North Dakota and in "North Dakota Horizons" and "Cowboys and Indians" magazines.