I just installed an outdoor silcock outside my basement. To avoid direct contact with the brick in the hole I drilled in a foot thick brick wall, I put a 1-1/4" PVC pipe and then the silcock inside it (it also makes it easy to replace and service).

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Should I put insulation foam inside the PVC pipe between it and the silcock? Right side of the picture (inside part), see the red arrow.

  • you could use plumber's putty
    – jsotola
    Aug 2 '19 at 3:46

I would make a 1" plug for each end so bugs don't get in. A hard foam ring would be what I would go for.

I would not fill with expanding foam or similar as that will glue the pipe in place.


I would have used a frost proof faucet with the longest shaft, usually 12", so the shut off with the "water in the pipe" supply would be closer to the heated area. I see that you installed a shut off valve to isolate and drain the discharge connection but I still would prefer a frost proof unit. My 2 cents.

  • It is 12" frost proof
    – amphibient
    Aug 1 '19 at 15:36
  • It is not frost proof if the seat of the valve is within a space that can freeze. It appears the seat of the valve is inside the brick wall. The seat of the valve needs to be inside the heated space of the home. If you fill the pipe with expanding foam it may or may not be enough to keep it from freezing.
    – Alaska Man
    Jan 5 '20 at 22:36

There are following reasons for sealing a space between pipe and wall:

  • Avoid airflow to reduce heat loss in a room.
  • The intrusion of animals e.g. insects must also be prevented.
  • The metallic pipe could come into contact with a surrounding other metal, which could lead to increased corrosion.
  • It is a pipe that must completely insulated for technical reasons.
  • It is a wall with structurally determined fire resistance.

A rough look shows that none of these points seems to apply here. Nevertheless, you would have to check that yourself.

Yes, insulation foam is possible. This could also be removed later if necessary. Another option would be rock wool and a cap in front of it. Or only a cap. With fire protection requirements, the implementation would be very different.

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