Frostproof Plumbing on Piers

[Hondarider]

I'm sorry if this has been covered, I couldn't find much when I searched it. What are common ways to frost proof plumbing at the transition from below the frost line in the ground to a house on piers? The Metal Pier guy told me that he's seen issues when people build a rigid box that ends up frost heaving and pushing the floor up, so some kind of slip joint is needed. Any links to more info and ideas are appreciated. Thanks

[ChugiakTinkerer]

I wish I had paid attention to the plumbing that went in to the cabins we built way back in the dreamtime of my youth.  This was in Fairbanks in the 80s and we were building 20x28 D-log cabins on piers.  There was about 30" of space between the ground and the floor joists.  The plumbing came in long after the framing was done so I never was involved in those details.  There were septic tanks and I think a community well for the subdivision.  So clearly that problem has been wrestled with for many decades.

You might check out the Alaska Cabins forum at OutdoorsDirectory.com. 

[Redoverfarm]

I'm sorry if this has been covered, I couldn't find much when I searched it. What are common ways to frost proof plumbing at the transition from below the frost line in the ground to a house on piers? The Metal Pier guy told me that he's seen issues when people build a rigid box that ends up frost heaving and pushing the floor up, so some kind of slip joint is needed. Any links to more info and ideas are appreciated. Thanks

I guess it would depend on how much heave you are anticipating given the area of your build.  The frost heave in the mid atlantic region differs from that of the upper mid west and etc..   Just a thought to lay your plumbing suspended on a absorbing material. Meaning that it will actually lay on a somewhat solid material and when it does heave that absorbing material will compress up to your plumbing pipes and not actually lift your pipes.  The depth of the material is determined by the amount of frost heave you anticipate.  Something like shreaded tires similar to that used in playgrounds.  You can still cover the pipes and insulate in the traditional fashion.  Just what somes to mind on an early Sunday Morning. 

I recently had a few stones pop off my piers last winter.  My fault as I laid them to the soil rather than creating an absorbing layer of crushed stone under them.  Those that I did lay that layer were unaffected by the heave as the stone absorbed that process. 

[akwoodchuck]

These are the go to guys...http://www.cchrc.org/

[DaveOrr]

Here in Yellowknife a good number of the places are trailers.
They are blocked up off the ground and then they are skirted and insulated around the perimeter.
Under the trailer there is a belly bag. This is an insulated tarp type deal that hangs down below the trailer.
The plumbing is mostly located in this area. The furnace has several ducts that warm this area to keep it from freezing.
Where the plumbing exits the bag to where it enters the ground it is either insulated (drain) or wrapped with thermostatically controlled heat tape (supply).

[Hondarider]

Thanks for the replies. I love CCHRC, I've watched a few of their videos, but I can't find anything pertaining to this. The insulated tarp idea sounds interesting, but I'd like to try to use the warm air from the house to keep it insulated and try to avoid electrical heat tape.

[DaveOrr]

Thanks for the replies. I love CCHRC, I've watched a few of their videos, but I can't find anything pertaining to this. The insulated tarp idea sounds interesting, but I'd like to try to use the warm air from the house to keep it insulated and try to avoid electrical heat tape.

The only areas where heat tape would be needed is where the pipes exit the belly bag before they enter the ground.

Here's an article that helps explain the systems used up here.

http://ykonline.ca/maintaining-a-trailer-in-yellowknife-part-3-pipes/

Some info on the materials used.

http://www.mobilehomerepair.com/underbelly.htm

If this system works up here where it can get to -70 it'll work for you.

[ChugiakTinkerer]

Cool info Dave, thanks for the links.