I have a bundle of foam and pipes coming up through the concrete ground in my backyard for my HVAC equipment. There is no conduit and the pipes and foam is all in ground contact and the concrete was poured around the bundle.

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How can I waterproof this and weather-seal it? When it rains the foam in the ground gets wet and I'm not sure if it gets absorbed down into the ground as a wick - or if it's a closed cell and it doesn't matter?

In any case, I was going to replace the rubber insulation but I also want to protect it from water so the foam that's embedded in the concrete doesn't get wet.

Can I just spray outdoor foam around it without having the expanding foam crush the pipes as it dries? Or is there an easier or better-looking alternative? The pipe only comes up a few inches before it elbows... so I'm not sure how I can make an enclosure that would fit and also not let it get wet from groundwater.

1 Answer 1


It's closed cell foam (or should be) - so water getting into it should not be an issue - worry more about the gnawed-off sections and get to replacing them, perhaps with a metallic over-wrap to slow down having them gnawed off again.

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