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Durable seal for steam pipe risers/concrete & plaster - apartment building

Durable seal for steam pipe risers/concrete & plaster - apartment building

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  #1  
Old 04-09-18, 01:08 PM
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Durable seal for steam pipe risers/concrete & plaster - apartment building

Hi everybody,

I live in a 110-year old building in NYC. There are a number of 2-1/2" iron pipe risers throughout the apartment, some are for hot and cold water and some carry steam for the radiators. Expansion and contraction over the years has significantly eroded the plaster/concrete ceiling where the pipes go in. This is a particular problem with the steam pipes, as every winter a lot of material rains down from the holes. I've been in the apartment for over four decades, but in the last few years the problem has gotten significantly worse. I want to make as long-term a fix as possible so I won't have to revisit it any time soon.

My thoughts are to install flanges and seal them to the pipes and ceiling, rather than try to patch the holes directly, and use a high-temperature caulk since the radiator pipes are scalding hot when in service. Am I on the right track?

The picture shows the hot water riser in the kitchen which was plugged with plaster a few years ago when I had some work done, and that clearly isn't cutting it.

Any advice is greatly appreciated, especially about specific products to use.

Thanks!
 
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  #2  
Old 04-13-18, 11:54 AM
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Location: California
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I am a plasterer. I know why what happened happened. I don't know of a qypsum product that will not do the same. You might tyry some furnace cement. Google it. I don't know if it will bond to the plaster or the pipe. I do have a couple suggestions about procedure: Clean the loose stuff around the hole. It will be softest closest to the pipe and get sounder as you go out. You will have to determine when it is good enough. You might have to install something like some metal lath of some kind of mesh or screen in order to give whatever new stuff you use something to hang on. There is no set way to do this in a case like yours. And if the hole is not too large maybe you won't need any other support. I can't picture your idea of a flange. I don't know how you will install a flange and still leave yourself room to get some sealing material behind it or above it.

Please do not feel badly that this answer was so long in coming. Sometimes we just don't have a good idea. As always the advice you get here is worth what you pay for it.

Let us know what you do and how it works.
 
  #3  
Old 04-13-18, 05:17 PM
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Thank you very much for that extremely informative reply, and IMO it was quite soon to be honest!

What I meant by "flange" is a ceiling/floor escutcheon of some kind, but it doesn't have to have any depth or attractiveness to it since I'd like it to blend into the ceiling as much as possible. That in fact appears to have been the original solution--looking at one of the pipes more closely today (not the one pictured in my first post), there's a flat metal shield still in place in the ceiling, HEAVILY painted over, but whatever was used to plug up the center hole crumbled away long ago, leaving about a quarter-to-half-inch gap around the pipe.

Unfortunately, none of the other pipes with the problem appear to have the shields still in place. Some removal of loosened plaster/concrete will be necessary, but I am reluctant to dig away too much, and would prefer to sweep it under the escutcheon if you know what I mean. Not only to simplify the job, but my impression is that the pipes need permanent wiggle room. They are risers which run the full height of a 12-story apartment building, and I'm concerned that the inevitable thermal/mechanical motion makes any brittle substance doomed to fail eventually.

My idea was to find something as close to the original flat shields as possible (a split or hinged ring of course), something I can paint over and be invisible when it's done. The idea was to squirt whatever adhesive on the top side and press it into place, once the ceiling is prepped that is, then dress the edge and fill in the center hole. Due to the size of the pipe (2 1/2" outer diameter) there aren't very many options online, and nothing that's flat.
 
  #4  
Old 04-14-18, 07:29 AM
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Location: California
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Perhaps another option is fire sealant. I don't know how flexible it remains and I don't know how it applies in overhead situations. Things do not bond well to friable material hence my suggestion to remove some loose material to get something sound enough to bond to.
And another thought Maybe you can stuff some neoprene or fiberglass pipe insulation and leave it shy of the surface in order to put something else there that looks better.
 
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