0

I'm working on improvising a shower to add to our existing clawfoot tub. It's just going to be the piping supported to the wall for now as we're going to redo this bathroom a year or so down the road.

Tub faucet http://www.vintagetub.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/R/M/xRM030P-CP-S.jpg.pagespeed.ic.LOyuGDd99e.jpg

Our tub faucet looks something like this and has no way to add on a shower to it, and the faucets with the showers cost a ton to add. So, since it's temporary, I'm going to T off of the supply lines after the valve. However, I don't know much of why the tub would be piped how it is.

The supply line comes out of the floor at a 1/2" and then into the valve and out at 3/8". I know this is done for sinks and such, but I don't know why or why they didn't use a 1/2" to 1/2" valve instead?

It comes out at 3/8" and goes through a short 3/8" copper line and then into the back of the tub. The 3/8" copper line is screwed into a (reversed?) 3/8" to 1/2" reducer. Then this was screwed into a (reversed?) 1/2" to 3/4" reducer which is screwed directly into the tub's faucet's pipe. I understand that the 1/2" had to be converted up to fit the tub, but why does all of the pipe downsize before it when the tub can fit a 1/2" line?

To retain the most piping and fittings, I'm following the same route with my shower valve, although it also accepts 1/2" lines. Is this the wrong approach, should I resize it all to 1/2"? And why would it downsize when it didn't have to?

I think the downsize can lead to faster water or increased pressure, but I couldn't find anything directly answering this.

Tub piping currently

  • So the idea is to tee off the supply lines (after the shutoffs), to feed a mixing valve for the shower? – Tester101 Feb 16 '16 at 18:11
  • @Tester101 Correct. – TFK Feb 16 '16 at 18:12
  • NOTE: If you wanted to, you could probably replace the existing shutoff valves with 1/2" x 1/2" valves. Then you wouldn't have to reduce to 3/8", then increase back up to 1/2". Though, you'll have to use an adapter since I'm not sure if shutoffs exist with 1/2" compression outlets. That's likely why they used 3/8" instead. – Tester101 Feb 16 '16 at 18:15
  • @Tester101 Why not use a different valve? And is there a benefit to downsizing? – TFK Feb 16 '16 at 18:43
  • 1
    Looks like the connection to the tub is threaded, so you'll either need compression fitting, or you'll have to install a union. – Tester101 Feb 16 '16 at 18:57
0

There is no benefit to "downsizing" the supply size; however, with tub fillers it usually is not a deal breaker because it just takes a bit longer to fill up the tub. If you look at the size of the tub filler spout, it may be no more of a restriction than you already have.

Both the stop valves and the threaded adapters that are screwed into your cast brass tub valve arms are available for 1/2" O.D. tubing (1/2" compression). Stop valves for 1/2" compression may be difficult (not impossible) to find in a "straight" configuration (as opposed to an angled 90° configuration), I would suggest that is the reason the plumber used 3/8" tubing and fittings.

How will an aesthetically pleasing shower mixer arrangement be created for this? I recommend that you consider changing the filler valve to a faucet set that has a shower diverter incorporated, there are many available styles:

enter image description here

  • It won't necessarily be pleasing to view, but it's only temporary. It's a secondary bathroom that has never had a shower and so it's never really used other than truly as a half-bath. So our goal is to get a working shower in now for cheap and redo the whole layout in a year or so. Although they do sale the sets specifically for this, they aren't cheap. I'm going to skip the compression fittings all together and jump straight to the 1/2" line for an easy hookup. – TFK Feb 17 '16 at 4:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.