# How deep to go



## Rancherii (May 29, 2008)

From Albany area of NY, how deep would you bury insulated pex pipe from garaged boiler and solar storage tank.


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## MrEd (May 29, 2008)

I am in a similar temp zone as you, and my plan is to go down at least 4 feet, 5 feet if I can get there. If you are using a backhoe, might as well keep digging. I guess if you do it by hand then your back will tell you when you have gone as far as you can :>)


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## Chris S (May 29, 2008)

I'm 80 miles south of you,  and building codes consider 4' to be the frost line.  In reality in 25years in construction I've never seen frost that deep except in disturbed ground.  Under grass, leaves etc frost rarely goes 1/2 way to the frost line.  
I install my lines below frost, as I don't want them where they can be damaged by the potential uneven movement of frost.  It seems though that many people don't go nearly that deep without isssues.  My theory has always been digging the hole is easy cleaning up the mess is not.  While the hole is open put in anything you could possibly need in the future ie  water line conduits for low & high voltage wiring communications etc.    1/2" & 3/4"   conduit is cheap- put in extra don't dig again
If you do this, plan on putting your low & high vlotage in seperate conduits -  that goes for any other communications wires too.


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## heaterman (May 29, 2008)

If it's insulated properly you don't have to go very deep, just enough to keep any surface traffic from disturbing the tube. We never go more than 30" m/l.
 If that surprises anyone, please re-read the first statement. 

Insulate. Insulate. Insulate.  Use the good stuff, not the pex, wrapped in bubble foil, stuffed in a drain pipe.


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## gpcollen1 (May 29, 2008)

Chris S said:
			
		

> I'm 80 miles south of you,  and building codes consider 4' to be the frost line.  In reality in 25years in construction I've never seen frost that deep except in disturbed ground.  Under grass, leaves etc frost rarely goes 1/2 way to the frost line.



I do not think anyone has recalculated the frost line for changes in climate.  I really think that 2 - 2.5 ft is good where i am and the book says 4 ft.


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## Rick Stanley (May 29, 2008)

Here's a dumb question: If the pex is insulated well enough to have zero heat loss if buried only 2 ft. or so down, even when going under a road or driveway that is plowed in the winter, will that 4-5 inches of foam, or whatever it is, provide freeze protection if the boiler is taken out of operation for whatever reason? Even if there's a cold snap of 30 below?


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## Chris S (May 29, 2008)

Going under a driveway is more critical as the frost goes deeper under driveways & roads & quicker.   I imagine an istallation in sprayed foam would be safer than a piped installation from frost movement.   
As far as safe - in a shallow installation, if the frost were all around the pipe.... What do the guys from Alaska think?


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## Willman (May 30, 2008)

Unfrozen ground temp is around 58* year round. I imagine it gets colder closer to surface. If its snow covered like this year ground didn't freeze but an inch or so. Several inches of closed cell spray foam is just what you need.
Will


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## heaterman (May 30, 2008)

9 times out of 10 we have the pex sprayed with urethane foam but under drives we do it a bit different. Starting about 3 feet on either side of the drive we lay 2" foam on the bottom of the trench which is smooth and level, then place 12" tall pieces of 2" on the sides. We then place about 2-3" of sand, no stones, on the foam bottom and wrap the pex with 1" thick rubatex closed cell insulation. We fill and compact more sand on the tubing to a level even with the top of the insulation and place 2 layers of 2" foam on top of that.  Basically we wind up with a foam box 2" on the sides and 4" on the top plus the 1" rubatex, (refrigeration grade insulation). We did a job like that last summer on a farm driveway that has heavy (think 80,000# loads) going over it daily. The drive did not settle and it showed absolutely no sign of heat leakage throughout the entire winter.


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## Willman (May 30, 2008)

> The drive did not settle and it showed absolutely no sign of heat leakage throughout the entire winter.


Just curios if you shot it with an IR camera ?
Will


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## heaterman (May 30, 2008)

Willman said:
			
		

> > The drive did not settle and it showed absolutely no sign of heat leakage throughout the entire winter.
> 
> 
> Just curios if you shot it with an IR camera ?
> Will



No, they haven't invented them up here yet.  

Suffice to say the ground above the tube remained frozen the same length of time as the rest of the drive. The owner reported that it had snow on it all winter.


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## JustWood (May 30, 2008)

My dad bought a Central Boiler last fall and did the hook up himself. Used the insulated pex from the dealer ,who said zero heat loss so he only buried it 24"  . I'd like to slap the dealer because the covered ditch never accumulated any snow all winter even at below zero temps.. Zero heat loss my AZZ.


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