Red sealant

Could someone explain to me about the red sealent.

What is it?

I have seen the sealant before. I thought this application was sloppy.

Is it really needed. It looks like ****.



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It is fire caulking.

So is it safe to assume that this was a homeowner attempt?

The same person that used a can of foam spray to try to stop a drain leak.


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It looks like high temp RTV.

I think they need to use it up at the roof, from the looks of the water staining on the joist.

Assume nothing. The fire caulk costs about $15 a tube, and it’s right next to caulk for $1 a tube. So what would a ‘home owner’ choose?


I’ve seen similar sealant used in an attempt to seal cracks in a heat exchanger. It was described to me as a high-temperature sealant.

Red RTV gets my vote, if it feels rubbery 98% chance it is.


yes, around here it is called red rtv but it is not at home depot ( at least not the good stuff) it is only available at the plumbing supply to plumbers, (not sure why) I had some applied to my heating system.