Running Cold Water Pipe


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Old 05-04-06, 10:50 AM
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Running Cold Water Pipe

I want to run water to a cabin on our property from the main house.Because of the layout of the house and the surrounding concrete patios getting out to the ground is difficult. The easiest and most direct route is through the garage. Can I run the pipe on the interior surface of the ceiling of a heated garage? Similar to what one sees in industrial buildings. Would it be o.k. to run it inside PVC pipe if it requires protection? The only other route available is the unheated crawl space above the garage. thank you.
 
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Old 05-04-06, 11:38 AM
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Sure you can. I assume you are considering copper so why run it inside PVC? If you are worried about the pipe "sweating" then insulate it.

On thing to be careful about: Garages need to be "sealed" from living quarters. When running the pipe if you need to come through a "fire-rated" wall/ceiling (i.e. from a "living space" into the garage) you need to seal that penetration to maintain the fire rating.

Another thing to consider is how/where this pipe will leave the garage to run underground to the cabin. You need to bury the pipe below the "frost line" in your area to prevent freezing. The hardest part will be to prevent freezing at the point it exits the garage and until it reaches below the frost line.
 
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Old 05-04-06, 04:51 PM
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One thing you will have to be aware of is the size of the pipe going to the cabin. Will you be able to tap into the initial 1" or so line servicing your house to go to the cabin. If not, and you choose to tap elsewhere, all you will get is 3/4", which may or may not provide enough volume to do what you want in the cabin.
Furd and I disagree (friendly) regarding copper and pvc, but you do need to make sure you adhere to frost line restrictions, as neither copper or pvc will be happy with cold weather.
 
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Old 05-05-06, 09:55 AM
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Thank you for your responses.
Yes, I was planning on running copper and was thinking about sweating.
The main house floor is about 3' higher than the garage floor. The pipe would enter the garage about 2'6" up the garage wall from the floor. It would not go through a fire-rated wall.
The pipe would then rise about 12' to travel along the ceiling about 20' then down to the garage floor. The garage wall is about 2' under ground on the side the pipe leaves the main building. It will then travel about 40' to the cabin.
Here there may be a problem with entry since the cabin is built on a pre-existing slab with no services. I was planning on drilling an entry close to the edge and digging under. "However, what would be required for insulation if I ran the pipe up about 1' and then entered the cabin? "I live in an area that only sees a couple of nights below freezing a year.
The pipe will supply water for a sink, toilet, shower and small water heater. I was planning joining the pipe to a 3/4" pipe. "Do you think this will supply enough water?"
In reading the local code I learned that one can use PEX. However, I read that it is subject to UV damage. "If I was to try this would I have to run it through conduit where it would be exposed to some light as in the garage.

Sorry for so many words. Just trying to get all the problems straight. Thanks.
 
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Old 05-05-06, 02:36 PM
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I don't see anything to be particularly concerned about your proposed system. I would insulate the piping in the garage and be sure to properly support/hang the pipng.

Just before exiting the garage (to the underground portion) I would install a shutoff valve (ball valve) and a tee with a threaded plug on the cabin side of the shutoff valve. The plugged tee would be useful for draining (or blowing out with compressed air) the line to the cabin if that ever became necessary.

I would also use flexible (type K or type L) copper in the underground portion and maintain the 24 inch depth from the surface grade. Make the transition from rigid to flexible inside the garage at the plugged tee. Since it is only forty feet to the cabin and flexible copper comes in sixty foot lengths it will not be necessary to have any joints in this line. However, if for any reason you do end up with a joint I strongly suggest that you use a flared joint and not soldered or compression fittings.

At the cabin I prefer your original thought of drilling through the slab, excavating under to install the piping and then refilling the hole. The problem with coming above ground and then insulating is that insulation by itself will not prevent freezing if the freezing temperature lasts long enough, is considerably below freezing (even for a relatively short period of time) or if no water is used at the cabin during the freezing temperature. Insulation only retards the heat in the pipe from being lost to the surroundings. Given enough time and without additional heat supplied (by using water) the pipe and the water in it will eventually reach the same temperature as the surrounding area.

A 3/4 inch supply should be more than ample for the uses you have stated. Up until at least the 1950's houses were regularly serviced by a 1/2 inch galvanized steel water line. Copper is generally accepted as having a greater flow capacity than the same nominal size of galvanized steel because of its smoother interior surface and resistance to internal corrosion. In the latter part of the last century the rule-of-thumb was that a 3/4 inch copper line was equivalent to a 1 inch galvanized pipe.

One last thing. If you have a PRV (Pressure Regulating Valve) on your incoming water line then I would suggest connecting this new water line ahead of the PRV and installing a second PRV in the cabin.
 
 

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