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lsblpn · Sep 28, 2012, 01:16 PM

I am running a supply line from my house to an outbuilding, where I will be supplying a bathroom (Complete with Shower), and a sink. I have done a trench 3 ft deep (Frost line in NC is 18 inches) to the building. I am planning on using 3/4 buryable pex.
My question is where is the best place to tap into my existing supply? I am on a well. Should I tie in close to where the well supplies my house or can I tie into any supply line? Does 3/4 inch pex sound appropriate? If not what would you guy's recommend? and how does the diameter of the line affect preasure to the destination?
Thanks
Larry

speedball1 · Sep 28, 2012, 02:10 PM

I would tee off from the nearest 1" or 3/4" supply. For your information here's how we rough in the drainage in my area./ Good luck, Tom

mygirlsdad77 · Sep 28, 2012, 03:06 PM

I would suggest running 1" pex for the main supply as the inside diameter of 1" pex fittings are about the same as the inside diameter of 3/4 copper pipe. Also, really you can tie in anywhere, but it would be best if you tie in after the pressure tank and pressure switch for the pump. Like I said, you can tie in even before the tank and switch, they do it all the time with yard hydrants, but best if you tie in downstream in my opinion.

lsblpn · Sep 29, 2012, 01:29 PM

Not much difference in price between the 3/4 " pex and the 1", how will this affect preasure at the destination?

ma0641 · Sep 29, 2012, 06:47 PM

Originally Posted by lsblpn

Not much differance in price between the 3/4 " pex and the 1", how will this affect preasure at the destination?

Pressure is somewhat meaningless as it doesn't vary with size. Volume is the issue. Go with 1".

lsblpn · Oct 1, 2012, 06:06 AM

Can you guys tell me what the typical step down from one inch pex supply line to the interior fixtures would be. I was thinking of running the 1" supply line to a 3/4" six outlet manifold. Does that sound appropriate, or should I step down further to 1/2"?

massplumber2008 · Oct 1, 2012, 06:11 AM

What fixtures are we talking about? How many shower heads in the shower? What size is the pipe you are cutting into to supply the addition and what size pipe feeds your entire house? What size water pipe supplies your water heater?

Finally, what PEX type are you using as some are full-size so 3/4" would actually be 3/4"?

Let us know...

lsblpn · Oct 1, 2012, 06:30 AM

Fixtures include: Toilet, Shower stall with one head, bathroom vanity sink, Washer connection, water heater supply, and a kitchen sink.
Was not aware that pex sized at say 3/4" would not actually be 3/4" can you elaborate on this? I was looking at Apollo Pex 1" for the main supply line, and stepping down to the appropriate appollo pex product for the interior fixtures.

massplumber2008 · Oct 1, 2012, 07:05 AM

Some PEX pipe/fittings are not what they suggest they are. Here, VIEGA PEX, for example, sells 3/4" PEX tubing and fittings, but the inside diameter of the fittings is actually 1/2"... makes the 3/4" a 1/2" pipe. In these cases, we run 3/4" PEX to all fixtures even though we would normally only feed 1/2" to each fixture. This is why Mygirl'sdad77 suggested stepping up to 1"...'cause many 3/4" PEX aren't 3/4" size.

On the other hand, there are other PEX types, WATTS (I think), for example, that have PEX fittings that say 3/4" and are 3/4" inside diameter. In these cases we run 3/4" main and branch off 1/2" to each fixture.

I am not familiar with Apollo PEX, but you should check to see how their fittings size at the inside diameter to make your final decision on sizing your main pipe to the addition.

If apollo is full-sized PEX fittings then you should only need to feed 3/4" to the outbuilding and since you only have one shower head you can feed 1/2" to everything and all would be fine. If you had multi. shower heads I would then advise you to feed 3/4" into the hot water heater and run 3/4" hot and cold to the shower for best result, but since you don't 3/4" isn't needed as a single shower head is reduced to 1/2" at the head, so no need for more volume...just a waste of pipe/money.

If the Apollo fittings are a reduced diameter then 1" supply is correct and 3/4" tube to each fixture is appropriate!

Finally, be sure the pipe size in your home is large enough to handle the increase in load you have added to your main or your main house could see a major drop in VOLUME when someone in the outbuilding uses water... ;)

Mark

lsblpn · Oct 1, 2012, 10:16 AM

Mark,
Awesome advice! Had no idea that manufacturers could vary like that. I really appreciate the good advice you guy's have given me, probably saved me thousands in cost as well as the headaches this surely would have caused.

lsblpn · Oct 1, 2012, 10:49 AM

One more question guy's
Shark bite fittings or Crimp? Willing to buy the necessary crimping tools, but probably will not have much need for them after this project.

massplumber2008 · Oct 1, 2012, 12:26 PM

Sharkbite fittings are SUPER expensive! The cost of these fittings VS the cost of a crimp tool, crimp rings and the apollo brass fittings will show that purchasing the crimp tool is the better option! You can also sell the crimp tool on E-Bay when you are done if you want!

Do a quick comparison of sharkbite elbows VS apollo elbows and crimp rings and see the difference... multiply the difference times the number of fittings and it should prove me right!

Good day!