I got a new gas person this year to check my boiler. He noticed that where my gas pipe comes into the house, through a hole in the bricks, the hole is sealed with cement or mortar. He said that this was bad because the expansion/contraction of the pipe against the cement would lead to wear and perhaps a gas leak. Is he correct or is he just hoping for some extra work?

EDIT: he may have said corrosion or even vibrations, I can't really remember. But how would cement cause corrosion?

  • 1
    Direct contact with cement/mortar can cause corrosion. Wear is a bit far-fetched.
    – Ecnerwal
    Commented Apr 7, 2021 at 14:18

2 Answers 2


The feed through a foundation or wall in my state requires a listed flanged pipe.

I don’t know what the coating is but there is a coating to prevent corrosion from contact with cement products.

The flange prevents movement of the earth causing a failure inside the home but I live in a seismic zone so movement is a possibility.

Would I go back and update an old home? Probably not unless a a service change was needed or insurance required it.


Sounds like extra charge. There is normally little movement and little of no force pushing the pipe against the mortar. Presumably the gas line is buried and experiences only small temperature changes to cause longitudinal movement movement ( radial movement would be essentially zero). Putting foam rubber insulation on the exposed pipe is bad. Rain wets it and causes fast corrosion. A neighbor did that and regular Sch 40 pipe corroded through in 15 years. When a service man replaced it the pipe came out in pieces.

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