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Steam riser flange in floor

algis Member Posts: 2
I have a steam riser that goes through the bathroom in an old 6 story NYC coop (1920s) building.

I recently retiled the bathroom, but found my tiles were cracking around the steam pipe even though I allowed 1/4" around the pipes. What I later realized was that the pipe is expanding up and down with a flange below the previously poured screed and the my newly poured screed and tiles going up and down for the ride.

My question is: How is the area around a steam pipe usually (or properly...) prepared for tiling? I'm guessing it should there be clearance right round for the pipe flange so the entire pipe can expand up and down... unless there is some sort of thermal expansion slip joint directly below and a flange is secured to each floor.

Photo shows flange under screed that has been cleared around its circumference - there is an even larger diameter flange directly below that flange

Btw: thermal expansion of cast iron (thermal expansion coefficient = ~6.5e-6) over 6 stories (60') over 150 degF = 6.5e-6 * 150 degF * 60' * 12"/' = almost 3/4" --> unless the pipe is secured at the middle floor (I'm on the third floor), there must be some sort of expansion slip joint every 6 floors or so..