What to use for water line out to detached garage?

jim_wilson · Oct 22, 2005

My summer project for the tractor was to dig out a hole for the foundation for my new detached garage. I finished the hole, got the permit for the foundation, and lined up a contractor to pour it, and then it started raining and the hole filled up - with 2 feet of water. And it isn't going down. So now I am off on other projects since I don't think the thing is going to drain before the weather starts getting too cold to do anything around here. The water table is high because we probably had 20 or more inches of rain over the course of a couple of weeks.

The project I chose was to waterproof the rear foundation wall of the house - which ties into the garage project because I need to run some conduits thru the wall for electrical and data cables. And I need to run a stub for a future sewer service out to the garage - and I need to run a water line. The only thing I am not sure what to use for is the water line. The original one coming into the house is a soft copper line that has been there for 45+ years now and seems ok. I had heard that the material of choice now is a plastic line. Anybody out there know what I should be looking for to do this? I wasn't planning on doing this work until next spring or summer so I hadn't really researched the choices yet. I am going to to tie in to the water service inside the house and just extend it out to the garage.

Farwell · Oct 22, 2005

In Michigan we use the black plastic pipe that comes in a roll. We bury it below the frost line which is 42 inches in my area of Mid Michigan. Many of us are on wells, not sure what the rules are for a city water systems. In California I used the ridged copper pipe for the house main supply from the city and the softer ridged copper for the rest of the house. The thing I did not do when I ran the pipe in California and wish that I had was to use 1 inch pipe for the main instead of 3/4 inch. I had plenty of pressure but not the volume that I wanted for a hose bib at the back of my property that caught on fire every 4th of July from kids and their fire works.
Another thing that I do on all of my water pipes is to use ball valves as shut off valves rather than gate or globe valves.
On your garage, think about raising the floor of your garage rather than digging out for it if your water table is so high. I had about 14 inches of sand for the base of my pole barn to help keep water out of it and you may need to do something similar. If you are going to heat the garage you may also want to think about putting 2 inches of foam board insulation and a moisture barrier under your cement floor.
Farwell

mrcaptainbob · Oct 23, 2005

Farwell sure is correct on those assesments! My last house had the 1" black (nylon?) feeding the house. THis place has 3/4". The pressure is adequate, but the volume is pitiful! In the throws of replmbing this ol' house and am using 1" every chance I get. The last thing will be a new well with a MUCH larger supply! You're doing all the right things. Make sure to provide 'tunnels' of PVC through the wall to fit the items through. When you run your items (electric, water, etc.) foam them in place. You could also run PEX for your potable water. Works well for hot and cold.

valleydweller1 · Oct 23, 2005

The local plumbing inspector told me that he black stuff "just barely" makes code, if you look at it it's only rated for 100 psi as opposed to 2-300 psi for PVC. PVC is probably a better long-term choice.

inveresk · Oct 23, 2005

Best pipe for water supply is alkathene. Size it 1" or above.

kayssupply · Oct 23, 2005

Let me start out qualifing my advice, I am a liscensed plumber of 25 years. All the above advise is pretty much dead on. I would add that the best is always copper. I personally have a rule of thumb, if a water line is under 100ft I use copper. Lately I have had to change that to 50 ft due to the terrible increase in cost. I personally used 1" roll Poly pipe for a recent pole barn project. The point I am getting to is that there are several grades of poly. I never use any rated less than 200#. It isn't usually a stock item but in pump counrty it should be available somewhere. It stands up to rocks , freeze, and even a good tug by a backhoe. I use brass insert fittings to splice and connect and always double clamp with " all SS" clamps. The bolts are sometimes not ss, be sure to check.
The short comings with PVC in your counrty is freeze and transition to other materials. The male and female connections are what has given trouble in the past. There is a brass compression fitting that has clamps to keep the pipes from pulling out that has just become popular around here. It has been a real life saver for me.

jim_wilson · Oct 23, 2005

Thanks for the replies. I figured my choices were pretty much either the soft copper or plastic of some form or another. After doing a little bit of research I found that the PEX type tubing that is used for plumbing radiant heat type floors and in house plumbing also appears to be a candidate. Copper appears to be the time proven choice though.

The actual garage floor is going to well above the water line. The garage is being built in my back yard which is on a little bit of a slope. It is the lower part of the foundation hole that has the problem - it is full of about 1 1/2 foot of water. It appears that after all the rain we had the water table is just very high around here. I don't anticipate it going down any time soon because as I write this it is raining out again. I thought about the foam under the floor idea too - I have pretty much firmly decided against it though. After doing some recent research that backs up some personal experience I have had with termites. All of the blown foam type insulations appear to have something about them that actively attracts termites. A couple of years ago while doing some extensive renovation to my house I found I had termite damage to the house right under the front door area. There was some of the Dow pink foam insulation right under the door area and it was riddled with termites. They had eaten into the wood - but actually seemed to prefer the foam for some reason given the amount of termite holes they had eaten into it. The last thing I want to do is build a structure with anything in ground contact that actually acts to attract termites.

hayden · Oct 23, 2005

I've used 1" poly pipe with success in the past, but I discovered what others have - there are a few different grades. The stuff from Home Depot is the lightest grade and is rated much lower than the good stuff. It also kinks very easily, and can crack if it does puncture. For all these reasons, I recommend to trip to a commercial plumbing supply house for a roll of the good stuff.

willfick · Oct 23, 2005

The squirrels absolutely love the black plastic stuff, too. I had some not buried enough on a sprinkler project and some leftover; they chewed it up voraciously. I don't know if it's the taste or the feel, or just the urge to destruct.
Wm

tawilson · Oct 23, 2005

I'm surprised to hear that. I've got a campground with hundreds of feet of it just laying on the ground through the woods. I get the occasional leak, but never have a problem with anything chewing on it, not even porcupines. And I have found the 160psi stuff at Lowes.