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PEX or PVC

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chaosracing

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Nov 14, 2015
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Okay, I am sold on PEX for my spring project to convert a 2nd floor bedroom into a bath. So I "was" planning to open the wall and run copper from the cellar to the 2nd floor. Is it a good idea to drill into the wall cavity from the cellar, AND on the 2nd floor, then shove PEX through the wall? My question relates to the post in this thread that the PEX has to be anchored to something. My way will let it "dangle" in the wall cavity. That is what I need an opinion on.

Thanks guys,

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In theory yes you could, just like if you were running a new electric circuit. Thats the beauty of PEX. Thats if you can get your holes to line up and drop a pull string to the basement.
 

johnnyradiant

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Vancouver, BC
Okay, I am sold on PEX for my spring project to convert a 2nd floor bedroom into a bath. So I "was" planning to open the wall and run copper from the cellar to the 2nd floor. Is it a good idea to drill into the wall cavity from the cellar, AND on the 2nd floor, then shove PEX through the wall? My question relates to the post in this thread that the PEX has to be anchored to something. My way will let it "dangle" in the wall cavity. That is what I need an opinion on.

Thanks guys,

.

By letting the pipe dangle you run the risk of hearing it when a valve is shut off or rubbing on the edge of the hole as it expands or contracts usually only the hot but a cold supply not used for long periods can warm to the room temp of the cavity then cool to the fresh cold water running through it.

There are clamps that are clip around the pipe and have to little ears on them that we use for hole bushings, called suspension clamp, they are commonly referred to as mickey mouse clamps due to their profile (top one). I would use one at the top plate and one at the bottom plate. If there is 'stuff' in the cavity you may need atleast one of the bottom corner clamps or something to hold it in a way not be be messin 'round with the other 'stuff'. I was using these long before I used Wirsbo but this pic is from a two year old uponor catalog. 1/2" #s are A7250500 and A7350500



Screen Shot 2018-01-24 at 9.52.40 PM.jpg
 

James-W

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Southeastern Wisconsin
I am helping a friend build a new house. He has a plumber running all the water lines and drains for the rough-in work, then the plumber will be back to install the rest of the plumbing stuff when we are ready for it. The plumber used PEX for all the water lines and quite frankly, I think it is wonderful stuff. I have no intention of doing this, but if I WERE going to replace the water pipes in my house, I would definitely go with PEX.
 

poppinjohnnies

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Dec 10, 2014
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342
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Kansas
I had a similar situation here - poor copper plumbing that was leaking under the slab (slab house). We re-plumbed using pex through the attic several years ago and I have no regrets.
 

laser3kw

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northen IL
I think it is wonderful stuff
PVC was thought to be the save all when it was introduced. Now, it's the red head step child of lead pipe. :spit:
I am wondering how long before the PEX couplings start to leak (like some many faucets) and then it will be poo-poo-ed.
 
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LifeLongWNYer

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Thanks for the replies guys.... The wall in which I'll be running the water lines is an interior wall, so no insulation to deal with, and there are no receptacles, or light switches, within 4 or 5 feet of the most likely cavity, so I am presuming there isn't anything for the PEX to rub against. I do have one of those "inspection cameras", so after I drill my holes, I can look around a little to see what the interior of the cavity looks like.

I was mostly concerned about the tube rattling around, so will use the clamps suggested by JohnnyRadiant.

Thanks guys, you helped a lot.


.
 

rlitman

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Long Island
PVC was thought to be the save all when it was introduced. Now, it's the red head step child of lead pipe. :spit:
I am wondering how long before the PEX couplings start to leak (like some many faucets) and then it will be poo-poo-ed.

While PVC has been around for much longer, PEX has well over 40 years in service behind it.

And in that time, there have already been scandals about both PEX fittings failing (both in metallurgical issues with brass fittings, and in plastic fittings breaking), and in the pipe itself developing pinholes.

Still, I believe that the current generation of fittings, combined with either PEX-A or PEX-B will give a better service life than type L copper.
 

Alchymist

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PVC was thought to be the save all when it was introduced. Now, it's the red head step child of lead pipe. :spit:
I am wondering how long before the PEX couplings start to leak (like some many faucets) and then it will be poo-poo-ed.

While PVC has been around for much longer, PEX has well over 40 years in service behind it.

And in that time, there have already been scandals about both PEX fittings failing (both in metallurgical issues with brass fittings, and in plastic fittings breaking), and in the pipe itself developing pinholes.

Still, I believe that the current generation of fittings, combined with either PEX-A or PEX-B will give a better service life than type L copper.

Can't speak for the plastic fittings, but pex with the brass fittings I installed 9 years ago retrofitting when we bought the house. No failures yet, including sweat fittings for pex to copper transition which I used in a couple places where I couldn't readily access copper to replace. As a bonus, 3/8 pex is used in our 5th wheel rv - though they used stainless clinch rings instead of copper compression bands. The copper bands fit tho.
 

JMartel

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Seattle, WA
Do Pex, in a home run manifold style setup. The Viega manifolds aren't cheap, but it's not that much more expensive than other manifolds once you add valves to the cheaper ones.

https://www.supplyhouse.com/Viega-51618-1-2-3-8-18-Port-Combination-Crimp-MANABLOC

In a home run system, you would use 3/8" and 1/2" lines. Pex has a smaller internal diameter than copper, but with only a single fixture requirement, it's more than enough. Showers, tubs, washer, hose bibbs all get 1/2" tubing. 3/8" for sinks, dishwasher, fridge supply, etc. I have zero water pressure issues, and I still even have 60 year old galvanized pipe from the city to my house that I'm sure has shrunk down in size. Set it up so you have minimal fittings under the house, behind the walls, etc.

Also, if you are starting from scratch, put isolation valves anywhere you can. My house didn't have a shutoff valve when I bought it. The meter shutoff valve didn't completely shut the water off, as I found out after cutting out the old piping. I've got a shutoff valve under the house where the supply comes in, a shutoff valve above the floor before it splits to the manifold and water heater, on the hot and cold before it gets to the manifold, and at every fixture. Makes working on things so much easier in the future without having to drain everything to work on one fixture.

Supply house is where I got everything, and in a pinch you can find stuff at Home Depot in the 1/2" size. 3/8" stuff won't be at home depot, though.
 
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Alchymist

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I ran every thing in 1/2" for home runs, 3/4" from pump/tank to cold manifold and water heater, then back to hot water manifold. Difference in price between 1/2 and 3/8 is nominal, and I only have to keep a few 1/2" fittings on hand.Reason for 3/4" to manifolds is that there can be two or even three appliances drawing off the manifolds at once. Made my own manifolds out of 3/4" copper with reducing tees followed by a ball valve at every T. A little work, but real sturdy manifolds.
 

JMartel

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The reasoning behind doing 3/8" tubing is that you have less water to clean out before you get hot water. Twice as much water in a 1/2" line as there is in a 3/8". That's twice as much waste. At most I waste about 2 quarts of water before it gets hot on the sinks. Short runs and as small of tubing as you need is the way to go.
 

u3b3rg33k

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The reasoning behind doing 3/8" tubing is that you have less water to clean out before you get hot water. Twice as much water in a 1/2" line as there is in a 3/8". That's twice as much waste. At most I waste about 2 quarts of water before it gets hot on the sinks. Short runs and as small of tubing as you need is the way to go.

Absolutely. if you right-size your home runs of PEX, then you won't NEED a hot water recirculation system. think about it - you probably don't NEED more than 1/4" ID for a low flow hand-washing sink...
 
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Showkey

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And there’s is nothing worse than a shower with low flow...............so upsizing has merit.
 

u3b3rg33k

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And there’s is nothing worse than a shower with low flow...............so upsizing has merit.

I'd agree with you there - especially since you want your tub to fill fast, and i've yet to see dual supply plumbing for a tub/shower combo. I can't imagine you'd need more than 3/8 for a shower stall, given that at 40psi supply pressure you should have more than enough flow to have good pressure at 2.5gpm.
 

NUTTSGT

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Checking out this thread again and getting some great information. So I strolled through the Menard's site and a have a question or two.

What's the difference between PEX and PEX-A ? One thing I noticed is that PEX-A is clear, does it come in red/blue ?

If I run new lines in the house, basement/crawlspace, the colors would be nice as a reference as to which is which. The crawlspace is rather dark.
 

Rusty Bolt

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PEX-A, PEX-B, and PEX-C are mostly interchangeable. They all come in several colors. The difference between them is how the polyethylene is cross-linked during manufacture. They meet the same standards.

PEX-A is more flexible, with a better memory, and is easier to un-kink with heat. That allows the use of fittings with expansion rings. Here is chart from PEX Universe showing fitting compatability: https://www.pexuniverse.com/content/types-of-pex-fittings

I use copper crimp ring fittings because they're the cheapest.

You want PEX that's approved for potable water. I think most (all?) PEX is OK for potable water. You don't need barrier PEX for drinking water, nor do you need PEX-Al-PEX.
 

Norcal

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Still not sold on PEX, but PVC is not for hot water, still prefer copper as have never been given a satisfactory answer about rodents & PEX, my house has a mix of copper & 1943 vintage galvanized, but been talking about getting rid of the galvy pipe since 1994, when it finally is done, it will be all copper.
 

JMartel

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If I run new lines in the house, basement/crawlspace, the colors would be nice as a reference as to which is which. The crawlspace is rather dark.

I used Pex-B. Mostly because the price was right and it had the most reviews on supplyhouse's website.

It also comes in white which I use for mixed hot/cold after the shower diverter valves.
 

NUTTSGT

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PEX-A, PEX-B, and PEX-C are mostly interchangeable. They all come in several colors. The difference between them is how the polyethylene is cross-linked during manufacture. They meet the same standards.

PEX-A is more flexible, with a better memory, and is easier to un-kink with heat. That allows the use of fittings with expansion rings. Here is chart from PEX Universe showing fitting compatability: https://www.pexuniverse.com/content/types-of-pex-fittings

I use copper crimp ring fittings because they're the cheapest.

You want PEX that's approved for potable water. I think most (all?) PEX is OK for potable water. You don't need barrier PEX for drinking water, nor do you need PEX-Al-PEX.

I used Pex-B. Mostly because the price was right and it had the most reviews on supplyhouse's website.

It also comes in white which I use for mixed hot/cold after the shower diverter valves.

Been a little bit busy and forgot about this thread. I appreciate the advice.
 

Johnson

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Central IL
As I refurbed my house, I added pex into the mix. I still have the main trunk of 3/4 galvanized but it splits off to threaded & barbed fittings and pex to new fixtures. Once the hot water heater craps out I will go to a manifold and home run setup. I am literally in the woods and have not had any rodent issues yet. But, good mouse cat takes care of most.
 

Handyandy23

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Ontario, Canada
PEX is also very easy to work on or add onto in the future. I understand what people are saying about home runs and limiting fittings, but depending on the situation it is certainly easy to tap into an existing line.

I added a humidifier on my furnace recently, and tapping into an existing line with a fitting is less than a 5 minute job of cutting with an exacto knife and crimping with the special tool. Same thing for when I switched from a single sink vanity to a double in a bathroom.
 

LifeLongWNYer

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Regarding "PEX A", "PEX B" and "PEX C", How do I, the average ( non-plumber ) home-guy tell the difference? Since this thread started, I have been in two big box hardware joints, and a local supply house, which is well known for the variety of "hard to find" things they routinely stock, considering that their specialty is plumbing.

In all three places, I carefully looked at the printed legends on the material in stock, and could see nothing which I could think was any reflection on the "A", "B" or "C" differences. ( Unlike copper tubing, which always has the type in the legend, as well as a color code to differentiate the grades).

THEN, I asked the oldest ( presumably most experienced/knowledgeable ) guy I could find, what the differences are. ALL told me there was no difference, and asked what made me think there is a difference. ( So much for the experience level of them )

My question is "is there a difference, and if there is, how do I find out what I am buying, before I leave the store?



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Hexen

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Regarding "PEX A", "PEX B" and "PEX C", How do I, the average ( non-plumber ) home-guy tell the difference? Since this thread started, I have been in two big box hardware joints, and a local supply house, which is well known for the variety of "hard to find" things they routinely stock, considering that their specialty is plumbing.

In all three places, I carefully looked at the printed legends on the material in stock, and could see nothing which I could think was any reflection on the "A", "B" or "C" differences. ( Unlike copper tubing, which always has the type in the legend, as well as a color code to differentiate the grades).

THEN, I asked the oldest ( presumably most experienced/knowledgeable ) guy I could find, what the differences are. ALL told me there was no difference, and asked what made me think there is a difference. ( So much for the experience level of them )

My question is "is there a difference, and if there is, how do I find out what I am buying, before I leave the store?

There is definitely a difference, explained at https://www.pexuniverse.com/content/types-of-pex-tubing and http://blog.supplyhouse.com/the-types-of-pex-pex-a-pex-b-pex-c-pex-al-pex/ , but if it's not labeled properly, I don't know if you can tell them apart readily in the store. Maybe try checking the retailer's website, which might have more detailed specs, and then you could know which item number to look for in-store.
 
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rlitman

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Only PEX-A can be used with expansion fittings. It is also the only type that can be repaired from a kink with a heat gun.
 

nadogail

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Coronado, CA
We, as a family, own a few rental houses. One is 17 years old, the newest is about 10.

All were built with PEX and none of them have had a problem attributable to the PEX piping.
 
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