Is There A Problem With Embedding Copper Tube In Concrete?

It is completely acceptable to bury/embed both hard drawn and annealed copper water tube in concrete. Decades of satisfactory service experience with the use of copper tube for in-floor radiant heating systems, water distribution systems and snow melting systems attest to the compatibility of copper tube embedded, encased or in contact with concrete

The copper tube must be completely embedded in the concrete and adequate provision for thermal expansion should be provided where the tube enters/exits the concrete.

It is also acceptable to run a copper water tube through a concrete floor or wall, provided that allowance is made for the lateral thermal expansion and movement of the tube and protection of the tube from abrasion. This can be done by insulating the tube where it passes through the wall or by wrapping the tube with an approved tape (to avoid abrasion) and installing it through a sleeve. Please refer to your local plumbing code for specific requirements regarding the protection of pipes and tubes passing through concrete and masonry floors and walls.

Both of the protection methods outlined above and the requirements listed in most plumbing codes are simply to protect the copper tube from the fatigue and wear caused by thermal expansion and movement. These protective measures are in no way dictated by the interaction of the concrete and the copper tube.

According to the Portland Cement Association the interaction of copper with both dry and wet concrete should not cause a corrosion concern. However, copper should be protected when it comes in contact with concrete mixtures that contain components high in sulfur, such as cinders and fly-ash, which can create an acid that is highly corrosive to most metals including copper.

A screened soil/pulverized limestone mixture is recommended as a selective backfill for copper tube to help eliminate corrosion concerns.

For more information on this topic, please review the following articles:

Corrosion of Embedded Materials Other Than Reinforcing Steel
[pdf: 1.2MB]

Corrosion of Non-ferrous Metals in Contact with Concrete
[pdf: 325KB]

Burying Copper Tube in Concrete or Mortar and Thermal Expansion Allowance
[pdf: 28KB]

Corrosion of Copper and/or Iron Embedded in Concrete or Plaster
[pdf: 305KB]