Freeze protection

[Ljohnsaw]

OK, I'm going way out on a limb, so to speak.  I figure someone as had this issue building structures in the North-East.

For my cabin, I have a low volume 24v solar powered pump for my well. (off grid)  I plan to have two tanks for water storage.  One potable for domestic use and one separate for my fire suppression (code requirement) indoor sprinklers.  I only need 300 gallons, by code, for fire.  The nice round tanks (like a golf ball) hold 325 gallons.  I would suspect that being spherical, they would be incredibly strong and you could bury them - not so, not rated to bury.  Only the 1,000+ tanks are rated.  I don't want to spend that much on big tanks and I don't want to dig that big of a hole (x2) - was hard enough for my septic!  Almost had to blast.

So, this is an unheated structure with the foundation wall that will be 12' tall - minimum 2' of gravel fill with a 4" slab on the inside resulting in 10' headroom.  On the outside, code requires minimum 2' of fill and I will probably go to 3'.  I cannot do more as, by code, I must keep 12' of clearance below the windows for snow accumulation.  I am using FastWall ICF blocks for my foundation that gives R21 insulation rating (so they say).

My thought is to make a small enclosed area wherever I have the most fill on the outside and provide as much rigid foam insulation around and on top of the tank as possible (10-20") leaving it open on the bottom to allow the ground heat to keep it from freezing.  Or, I could make a pit, more centered in the floor, down to dirt through the slab/gravel which would put the base about 3' below grade.  I could probably go a little deeper if that helps.

Winter lows are generally around zero Fahrenheit and may dip to -10°F.  How far down is the "stable" 54° level?

[Brian_Weekley]

I don't have an answer to your question, but I'd like to hear more about your solar well system.  How deep is the well?  What system did you get?  Off-grid, how would the indoor sprinkers work?  How do you move your potable water?  I've often thought about using a solar pump to fill a water tower for use, but have the same cold climate concern.

[thecfarm]

I think you have something like my root cellar. We have a sunroom,about 10X12 feet. Under the sun room is our root cellar.This is just cement walls,6" thick. No cement floor,just dirt. One side does open up into the basement. This has a insulated door,like a house door. I use all 2 inch syrofoam,the blue stuff,for insulation,on the walls and ceiling.Caulked all the seams and where ever there was a seam I put some caulk to it. Crushed stones on the floor. Having no cement on the floor keeps that room at a good contance temp. Does not go lower than 44°, and goes up to about 48 when it's kinda warm out. The 44° is when it's below zero and in the single digits.I have never seen that room in the 30's. The contractor's Father came over when we had the walls poured and he said that would be a great room for a root cellar. I was going to have cement for a floor. He had one in his camp. He invited us over to see it. We did it the same way he did his. Works great. Hope this helps.

[Ljohnsaw]

thecfarm,

That is VERY reassuring!  I think I will plan to do the "sump" type setup.  A hole through the slab (not poured in this section) as deep as I can get (probably only 2 or 3 feet into the earth - too many rocks) and build up walls.  I picked up a huge pile of 1-3/8" Styrofoam insulation that I could use for this.

Brian,

My well (as documented in another thread) is only 140' deep with a 25' static level.  I went with a Simple Pump and 100' of pipe.  I will buy the motor head next year - I just installed the handle for now (hand pump).  There is a tiny weep hole 48" down well for freeze protection (when not pumping).  It takes 4 strokes to bring the water up and 15 strokes/gallon.  The 24v version is capable of producing just over 3gpm.  I will power it with it's own cells with no batteries to service or worry about. 

I will have an RV pump and 20 gallon pressure tank to take care of the domestic use along with a tank-less propane hot water heater.  I will have a battery/solar setup for LED lighting and the domestic pump.  For the sprinklers, I will am in the process of the design work for that - just signed a contract for engineering services.  They are aware of my situation and it will either be a 24-48vdc or I will have to install an inverter of the appropriate size to run that pump if it should ever be called on - hopefully never!  I will up-size my battery bank to have the reserve necessary to meet the fire demand.  It's not much - I think its less than 10 minutes to dump the 300 gallons of water with a 50 gpm pump.