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Plumbing new second floor radiator
I need to install the plumbing from a second floor bedroom down to basement for a new run of Baseray baseboard rad. I have a two pipe vapor steam system. Once I get the piping down to the basement, it's easy from there. However plumbing the vertical riser and elbows into the baseboard rad is my question. Is there a flexible tube solution suitable for steam? How much wall do I need to open up (wet plaster in excellent condition, btw). How does one cross though any top plates? How would a master plumber do it?