3/4" or 1/2" copper lines

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by artmg, Jan 30, 2007.

  1. artmg

    artmg New Member

    I'm putting a new bathroom on the third floor of an old house. All of the water lines are now 3/4" copper. Is it necessary to run 3/4 up to the third floor before switching to 1/2" or can I make the risers all 1/2"? The lines will be about 30 feet long with maybe 6 or 7 elbows.
  2. Rancher

    Rancher Guest

    Bathroom = Shower ???

    1/2" will reduce the flow to the shower head, and to the sink faucets, you probably don't care what the flow is to the toilet. You also lose 4.3 psi in pressure going up from the 2nd floor to the 3 floor. So it's up to you whether or not to save a little/lot of money using 1/2" vs 3/4" copper.

  3. Terry

    Terry Administrator Staff Member

    Bothell, Washington
    I would run the cold in 3/4" before you branch off for the 1/2" lines.
  4. artmg

    artmg New Member

    Why just the cold? Although I was concerned about it taking the hot too long to get up to the third floor and wasting water. The cost was really the big factor, $10.50 a length for 1/2" and 15.50 for 3/4. It isn't that much in the grand scheme of things but why spend the extra if it doesn't matter. The bathroom will have a tub with shower, toilet and sink.
  5. prashster

    prashster New Member

    If it were me, I'd run 3/4 to the shower and then 1/2 to the sinks and toilet.

    If yr really concerned with cost, then have you considered PEX or CPVC?
  6. TedL

    TedL New Member

    NY Capital District
    For one thing, the toilet uses only cold.....

    Based on pricing in my area, it sounds like you're using type M (red lettering ) which is not code in my area for potable water.
  7. kordts

    kordts In the Trades

    exurban Chicago
    Good lord you are a tightass. You aren't going to pull a permit, you aren't going to vent your toilet because you don't want to cut a hole in the roof. You ask for advice then spit in the faces of those who respond. Why even bother? Do what the hell you want. It'll suck, but you'll be happy because you did it cheap.
  8. artmg

    artmg New Member

    No Korads actually no I'm not a tightass and I would rather not spit in any ones face even a goofy face. I have to face reality. I'm 72 working 800 miles from home and working alone. I'm taking what ever tools I think I might need in a small car and that doesn't include a 40 foor ladder. The temperture will be in the teens, the roof is a 12-12 pitch made out of slate etc etc etc. I'm doing the job for free for an elderly woman who needs to rent out some space in order to keep her house.I'm not pulling a permit because that would bring on a higher assessment which is the reason she can't afford to live there in the first place. I'm paying for most of the supplies myself out of my social security check. I woud buy the 3/4 if it were necessary but why put in more than necessary. My concern was pressure and flow nothing else. I'm sure you routinley put in 1" copper lines just because they are bigger the hell with the cost right. Hell you probably put in copper drain lines too ...only the best I'm sure and you don't charge a penny more and you never cut corners. I know that side wall vents work I've seen enough of them in my day and I know they are illegal. I'm not sure that it would work in this case and that is the only reason I asked. If it wouldn't work then I wouldn't do it I'm not stupid. I can program a computer in three different languages, repair a transmission, anti lock brakes locate an electrical short in a Lexus faster than you can take a piss, frame a complex roof, build spiral stairs, carve ornate wooden designs, repair electronic equipment, weld ARC,MIG,TIG, blow glass and just about any other damn thing you can think of. So think about me the next time you have someone change your oil or fix your VCR. I've seen jerks like you my whole life. If you don't have something worth while to say then don't say a thing. People are on this site to get information not be insulted by the likes of you.
  9. Sparty007

    Sparty007 New Member

    I'm not sure which one of the previous two posts I laughed at more......

    Simmer down fellas. :D
  10. Gary Swart

    Gary Swart In the Trades

    Yakima WA
    Type M copper is quite legal in most places for potable water. Of course local authorities sometimes have their own rules, but type M will be just fine. I think you'll be satisfied with 1/2". Volume may be a bit less than with 3/4", but not enough to worry about.
  11. norcal1

    norcal1 Plumber/Owner

    Well said...try not to take it personally, the hot shots have insulted me (a fellow plumber) on more than one occasion, as well...you're in good company. :D
  12. not to hurt you, but...

    for the record:

    information only.

    take no action.

    There are phonies and game players who sign in, and sometimes they know a lot too. At least one person signs in under multiple aliases and re-phrases recent posts, and it could be anyone! It might even be the man who owns and runs the vBulletin software, just to create flow and content, and thus to support his "client". I have seen a 100% similar pattern over at the JBF site, which also usees vBulletin, and over there the oldtimers interact with the phoney so that he eventually comes 'round to agreeing to buy the current sponsor's products. That is a win-win configuration.

    Back to your case, Mr. "artmg". I have seen a lot of people posting that they are old and doing a lot, for free, for people in need. FINE. So be it. You are an awfully feisty fighter. Not what I have seen in my long life, when someone is a 72-year-old. Hmm.

    But still, you do know a lot, and you are worth having around, in my opinion. You are not making us work uselessly, spinning our wheels just so that the sponsor can get plugged and recommended, and not for the purpose of misinformation either. (I have also seen that happen!)

    Just please remember that volunteers like to be appreciated, and a $10 - $15 difference in this post is what sparked a normal human reaction, in addition to whatever you wrote in the other posts... I really really hope that the little old lady has been consulted about your cutting corners, and that you have spent a lot of time educating her on all options and decisions. For free. And later, when she starts collecting rent, I hope you help her understand what it means to be a landlady and how to deal with tenants. That work is for free, too, since that is what she has come to expect. Let her have the new money coming in. It'll enable her to have a better lifestyle (keep her house, for one thing).

    Other people make money while we help for free. Ours is not to question why, our is to do or die. Welcome to the crowd. Helping people in need is just fine by me.

  13. Racer814

    Racer814 New Member

    run 3/4" cold up the wall then split to 1/2" after the shower...this will give you the pressure you need

    run 1/2" hot up the wall and to the fixtures...you don't need as much volume of water on the hot side...all you are doing is tempering the water...in fact it can be counter productive if you are any distance from the WH as you will have that much more volume of water to exhaust before it starts to get hot when you turn on the shower/sink

    it's not about cost of 3/4 vs 1/2 at all... thats how I would do it...
  14. kordts

    kordts In the Trades

    exurban Chicago
    hey mo,
    simmer down. Sorry to call you a tight ass, but you are doing an illegal installation. Sorry it's for a broke old lady, but that don't make it right. Now she has a got a tenant with a DIY bathroom. Props to all your mad 72 year old skilz, but this is a plumbing forum. Most of the people giving free advice are professionals, who are basically cutting our own throats by giving away the knowledge that puts pork chops on the table. I don't mind helping people out, I do a lot of free stuff. I plumbed a Habitat for Humanity house last year. I usually lose money when old broke widows call me. The plumbing has been neglected for years, until when a water heater lets go, or a galvanised drain pipe finally closes up. So, let's not get into who's holier than thou, we all know that Led Zeppelin are the only ones to live in the houses of the holy. But your are basically doing a job that needs to be filed inspected, by not doing so, you are cutting the throats of some poor schmo like me who is running a legit business. By the way, I love pvc drains, copper drains are for specific purposes, like commercial dishwashers. 1" copper is overkill, for your scab job. Volume not pressure is the key. 3/4" is fine.
    Peace out,
    Kordts, the 43 year old jerky boy
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