Which material is recommended to replace a section of cast-iron pipe?

When replacing a section of cast-iron pipe, the recommended materials are plastic or coated steel due to their properties that provide durability and resistance to corrosion. Plastic piping, such as PVC or HDPE, has become increasingly popular in plumbing because it is lightweight, resistant to chemical damage, and doesn't corrode like metal materials. Coated steel also offers support and a barrier against corrosion, making it ideal for various applications in plumbing systems.

Using concrete is not advisable for replacing cast iron in most plumbing applications, as it is rigid and heavy, which can lead to structural issues or difficulties in installation and flexibility in the system. Wood is not a suitable replacement material either because it can rot or degrade over time when exposed to water. Iron, while it is similar to cast iron, is prone to rusting and generally requires protective coatings if used in plumbing, making it less desirable for replacement when better alternatives exist.

The choice of plastic or coated steel ensures continued integrity and efficiency of the plumbing system while minimizing potential future issues such as leaks or corrosion, making it the most appropriate selection when replacing cast-iron pipes.