Replacing old shower arm with 1/2"
#1
Member
Thread Starter

The shower arm in my upstairs bathroom was probably installed when the house was built, in 1926. It's too small in diameter to fit a modern 1/2" shower head, so I need a new larger shower arm installed. I'd like to get an idea of how this can be done, if anyone here knows.
#2
Probably cast iron plumbing, could open an area in the wall and change the fittings. Not a lot of detail to work with!
#3
I've never seen any other size other than 1/2" used.
1/2" NPT (national pipe thread) is 1/2" internal diameter and roughly just over 3/4" outside diameter.
1/2" NPT (national pipe thread) is 1/2" internal diameter and roughly just over 3/4" outside diameter.
#4
Yeah I've run into 3/8" pipe once or twice.
No way to change your elbow without opening up the wall on one side or the other. And you might find more small pipe and need to use a galvanized 3/8 x 1/2 reducing elbow.
No way to change your elbow without opening up the wall on one side or the other. And you might find more small pipe and need to use a galvanized 3/8 x 1/2 reducing elbow.
#5
Forum Topic Moderator
Have you considered keeping the shower arm as is and just adapting it to a modern 1/2" pipe? Something like this:
https://www.lowes.com/pd/B-K-1-2-in-...ing/1000505549
I wouldn't necessarily want to start replacing pieces in something that's obviously that old since you may end up having to replace way more than you want to.
https://www.lowes.com/pd/B-K-1-2-in-...ing/1000505549
I wouldn't necessarily want to start replacing pieces in something that's obviously that old since you may end up having to replace way more than you want to.
#6
Member
Thread Starter
Thanks everyone who replied. The plumber opened up the wall enough to see, and said that because the pipe up to the shower arm was an old fashioned type - with a ball joint or something? - if I wanted a 1/2" shower arm, he'd have to run new pipe all the way up from the basement. Thanks Zorfdt for the suggestion, the plumber used a fitting like that instead.