Need PEX Plumbing Advice for Bath Remodel

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Mathelo

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I'm doing a complete remodel of our hallway bath on the second floor. When done, I'll move on to the master bath. This house is 50 years old and I'm on well water and the main line is 3/4".

I've ripped out everything to the studs and floor joists including the existing copper plumbing. I'm replacing with PEX.

I've considered the different arrangements for PEX - home run, trunk and branch, and zone. I'm inclined to go with home run but I can be persuaded to go with one of the other approaches. My objective is to maximize volume / pressure at the shower and eliminate pressure change at the shower when another outlet is opened.

As the bathrooms are almost directly over the water supply in the basement I don't expect much delay in getting hot water to either bathroom. The PEX runs should be about 50 ft.

Everything I've read says I'm probably okay with 1/2" to the tub/shower combination but I'm inclined to up size to 3/4" to reduce any pressure loss. I'd home run everything else although I'd consider trunk and branch for the cold line to the sink and toilet. I could also share these other 1/2" lines with the sinks and toilet in the master when I redo that room.

But assuming I home run everything, I can't find a manifold that includes both 1/2" and 3/4" outlets? Does such a thing exist? I know I'm not the first person to do what I'm suggesting.

Thanks in advance for any advice.

Louis
 

ImOld

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I've always found that the beauty, as in artistic beauty, of plumbing is that you can construct or put together whatever pieces needed to accomplish your task.

As long as you stay within the legal and safe bounds of your creation, there are endless pieces-parts to get from point A to B.

What I don't like about pex is it just sort of sits there as some sort of bendy thing.

Now, cleaned and polished copper connections forming sharply defined geometrics, that is real plumbing.

The working plumbers will be along shortly to address your question in their usual work-a-day mundane fashion.

Not that there is anything wrong with that.
 

Jim Mills

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Pick a method & go with it. Neither is life changing. I am an old copper guy myself & am having a hard time switching to pex, but have done some. I will say that I am unimpressed when I see one of those huge manifolds with a million red & blue "home run" lines hooked to it. JMHO though. What size pipe do you have coming off the meter? If you have 3/4", you could do a "trunk & branch" & use 1" pex (which is more closely sized to 3/4" copper) for your trunks, and 1/2" pex for your branches. I just did a 4 unit apartment building with this system, and with all new fixtures & pressure balancing shower valves, I have gotten nothing but positive feedback so far.
 

Mathelo

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... I will say that I am unimpressed when I see one of those huge manifolds with a million red & blue "home run" lines hooked to it. JMHO though.

Why? My manifold won't be huge but why does it leave you unimpressed?

What size pipe do you have coming off the meter? If you have 3/4", you could do a "trunk & branch" & use 1" pex (which is more closely sized to 3/4" copper) for your trunks, and 1/2" pex for your branches. I just did a 4 unit apartment building with this system, and with all new fixtures & pressure balancing shower valves, I have gotten nothing but positive feedback so far.

I'm on on well. No meter. Pipe in is 3/4".
 

hj

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quote; but why does it leave you unimpressed?

One reason that any dummy can do it. Red PEX from the hot manifold to the left side of the fixtures. Blue PEX from the cold to the left side of the toilets and the right side of the other fixtures. Just snake the tubing from point A to point B, that is something a 5 grader could do. And it was basically what companies were doing when plastic pipe came out. Have the plumber install the "anchor points" then have high school kids run the pipes because it took absolutely NO talent to do it.
 

Jim Mills

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Another reason would be that it (I'm guessing) sounds like your home is currently plumbed "trunk & branch" and now you are re-doing part of it with a manifold system, which gives you at best a "hybrid system"? or in other words, a "Hodge-Podge" system of pieces, parts, & materials.
 

Tom Sawyer

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Another reason would be that it (I'm guessing) sounds like your home is currently plumbed "trunk & branch" and now you are re-doing part of it with a manifold system, which gives you at best a "hybrid system"? or in other words, a "Hodge-Podge" system of pieces, parts, & materials.

I find home run manifold systems to be a big waste of time and money.
 

Mathelo

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One reason that any dummy can do it. Red PEX from the hot manifold to the left side of the fixtures. Blue PEX from the cold to the left side of the toilets and the right side of the other fixtures. Just snake the tubing from point A to point B, that is something a 5 grader could do. And it was basically what companies were doing when plastic pipe came out. Have the plumber install the "anchor points" then have high school kids run the pipes because it took absolutely NO talent to do it.

And why would that matter? Simpler and easier are generally considered good things so long as quality and reliability aren't given up in the process.
 

Mathelo

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Another reason would be that it (I'm guessing) sounds like your home is currently plumbed "trunk & branch" and now you are re-doing part of it with a manifold system, which gives you at best a "hybrid system"? or in other words, a "Hodge-Podge" system of pieces, parts, & materials.

Yes, the house is currently all copper but the bathrooms can be thought of as its own zone while the kitchen and laundry room at the other end of the house is another. I'm focusing on the 'bathroom zone'. "Hodge-Podge" is a subjective idea here. Not at all sure what difference it makes.
 

Mathelo

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I find home run manifold systems to be a big waste of time and money.

Can you expand on this? I'm not wedded to the idea of a home run system and it does seem that for my setup a trunk and branch (or even zone) would be easier but I want to get maximum pressure and flow at the shower / tub without fluctuation when another faucet is opened or toilet is flushed.

A benefit to the home run design that I like and don't often see discussed is having a shutoff valve at the beginning of the line for each fixture. As a home owner I've always found it frustrating to have to shut down a complete group of fixtures - or the whole house in some cases - when working on a single fixture. Sometimes the shutoff valve at the fixture is enough but not always. And I've never seen these on tubs or showers.

I'd like to eliminate this problem going forward and the home run seems to be the only way.
 

Houptee

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I used 3/4 x 1/2 branch mini manifolds on my house. I ran 3/4 to them and branched off under the bathroom and kitchen with 1/2 to each fixture. Works fine.
 

hj

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quote; Simpler and easier are generally considered good things so long as quality and reliability aren't given up in the process.

Did I say they were NOT compromised by the way it is done? The reiiability depends ENTIRELY on the person making the connections and his diligence in maintaining said equipment. Quality? Come back in a few years and we will talk about that.
 

Mathelo

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Did I say they were NOT compromised by the way it is done? The reiiability depends ENTIRELY on the person making the connections and his diligence in maintaining said equipment. Quality? Come back in a few years and we will talk about that.

What sort of maintenance are you suggesting?

In any case, copper really isn't an option unless you can tell me how to get copper pipe into floor joists without tearing up the house.
 

ImOld

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I'm always admonishing people over the fact that they don't just stop and think.

So you believe that the gazillion homes in the world with a gazillion miles of copper pipe installed, have torn up houses.

Regardless of the pipe material, holes need to be drilled or material needs to be notched, modified, to accomodate the pipe.

Or do you believe that pex can just be snaked thoughout a house willy-nilly from point A to B and everything that needs to access that supply of water just magically adheres to it.
 
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Mathelo

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I'm always admonishing people over the fact that they don't just stop and think.

So you believe that the gazillion homes in the world with a gazillion miles of copper pipe installed, have torn up houses.

Regardless of the pipe material, holes need to be drilled or material needs to be notched, modified, to accomodate the pipe.

Or do you believe that pex can just be snaked thoughout a house willy-nilly from point A to B and everything that needs to access that supply of water just magically adheres to it.

Let me be specific. I have 7 2x8" floor joists at 16" OC that now have been sistered to stiffen the floor. I'll be laying porcelain tile when all said and done. How do I lay copper without weakening the joists? I will not notch. The holes need to be in the center of the joists. The only way I can see to get copper pipe through these joists is to cut it up into 14" pieces and re-assemble with several couplings and solder once in. That doesn't sound like a good plan to me.
 

Reach4

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Soft copper "type L" may be allowed in your area if you wanted to avoid PEX or PEX was forbidden.
cefc3412-feb4-41a5-ac8f-d505b2737684_300.jpg
 

Jim Mills

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Mathelo, I don't think anyone has boo-hoo'd you suggested use of PEX. It's your idea of using a manifold supplied by a 3/4" line that has branches of both 1/2" & 3/4" that had me questioning your method. That's just a bad idea, and why you wont find a manifold built that way. As far a using 1/2 or 3/4 to you shower, we just don't have enough information to give you an answer. If you are installing a multi head shower, run 1" PEX (eq. to 3/4" copper) to the shower, and tee off of it with 1/2" PEX to everything else. You'll be fine. My house is plumbed with copper trunk & branch, and when I am in the shower in the AM & I feel a slight & momentary drop in pressure, no change in temp though, because I have a pressure balancing valve, It gives me a warm fuzzy feeling because I know my wife is up & at the kitchen sink making the coffee.
 
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