frost depth???

Anonymous-0 · Jan 19, 2012

Hey folks,
this may sound like a loaded question, but I just hit a snag that I need to figure out how to work around.....

I've got these frost free hydrants and am at a point to install them. Frost point that the utilities go by is 80 cm (31.5 inches) min with 1 meter (40") suggested..... Got my area open for a trencher and asked the local guy about digging it... No problem, but he said that most of my back yard is a big rock at 20-24 inches.....

Worst winter I know of in this area had about 10 weeks of 10-25 degree temps.... Any idea how long it takes ground to freeze to a 2ft depth (no traffic over it)... Talking about 60 ft and 1" black plastic pipe.....

Or, what if I ran 2 or 3" and shoved the 1" thru with heat tape?

Thanks, Dave

Anonymous-0 · Jan 19, 2012

I would say to be safe, to go down at LEAST 25 feet.
If not more.

Anonymous-0 · Jan 19, 2012

(quoted from post at 04:24:56 01/19/12) I would say to be safe, to go down at LEAST 25 feet.
If not more.

shouldn't be on the bottle that early in the morning.... Now behave yourself....

Anonymous-0 · Jan 19, 2012

Im sorry...Just some coffe with a little cream is all...LOL

rick2 in ohio · Jan 19, 2012

hey dave i also am getting ready to put in two
hydraunts kinda waiting for the weather to cooperate
a little more think im gonna rent a small excavator
to dig mine
RICK

Anonymous-0 · Jan 19, 2012

(quoted from post at 04:43:07 01/19/12) hey dave i also am getting ready to put in two
hydraunts kinda waiting for the weather to cooperate
a little more think im gonna rent a small excavator
to dig mine
RICK

where are you in OH and how deep are you going? I'm from the Athens area and we get about the same winters over here....

George Rausch · Jan 19, 2012

I understand that PEX tubing, comes in rolls, no joints, will freeze and expand and not break, it just expands out as it freezes. Then thaws and comes right back.

D7fever · Jan 19, 2012

My father who was a carpenter always put any foundations ,feed pipes etc 6ft below. should not freeze at that depth. We are in MA. I know that a lot of contractors say 3-4 ft, but if we have a cold winter with no snow, frost gets down a lot further than that. I would say that if you are restricted on depth because of ledge that you use some insulation on your pipes, and maybe around your valve . Have fun.

Anonymous-0 · Jan 19, 2012

Dave, don't count out black plastic pipe, it's nearly as elastic, as pex, just be sure to use gray plastic fittings, all the way to your hydrant. Another little trick, is to leave a constant trickle of water, to a trough, with an overflow drain. Water stays fresh, NEVER freezes!

showcrop · Jan 19, 2012

I had the same problem 22 years ago. I back filled about six inches of sand then laid in 2" foamboard insulation over the sand through the shallow part. No problems in 22 years.

Anonymous-0 · Jan 19, 2012

DIY Dave: I'll be using one length of plastic pipe going in to an adapter at the hydrant (2ft back on a galvanized pipe as advised before). the trickle is doable but don't really want to. Have to see.....

Showcrop: did you insulate the pipe itself or just do the sand and lay the foam on top? Styrofoam should be OK also?

TonyIN · Jan 19, 2012

Dave...

Not 100% sure about Athens OH, but southern part of Ohio up through Dayton, footer frost depth is 30". In ripping dirt with an excavator, worst I"ve seen in the last 10 to 12 years has been 12" to 18" thick slabs of frozen dirt - that was in Cincinnati, undisturbed dirt, on a dry cold winter.
Based on what you say about your weather and local dig depths, I would think you"re probably ok - but go as low as you can then take the other suggestions about some pipe insulation and sand.
The frost depth is setup for the building codes and there is some factor of safety in their methods...
By the way - Athens area is some pretty country. Spent a week out there working on their high school stadium this summer.

Tony

wijim · Jan 19, 2012

2in foam isulation should do it. Jim

MarkB_MI · Jan 19, 2012

Cover top and sides (but not the bottom!) of your pipe with foam board insulation. That will give you a bit of a margin over the normal freeze depth. Your other option involves dynamite.

BushogPapa · Jan 19, 2012

I would be concerned with the Hydrant Drain...

I would put coarse stone in a pit, under the hydrant, for the draining water to get away..
May be a good idea to insulate the exposed pipe on the hydrant.??
Have you checked to confirm the soil depth..?
If it is not real tight rock, you still may be able to get some more depth..
The 2" Styrofoam sounds like a great idea..

Ron.

Billy NY · Jan 19, 2012

We have that exact same problem at the farm, rock is a couple feet down, need a hoe hammer on a skidsteer, backhoe, excavator, to get to depth or cover with foam insulation board, keep traffic off those areas if possible. Same pipe, fittings and hydrants. When the line was put in, inside the barn, they figured frost would not be that deep, I had to dig up the section crossing aisle and lower it, then used foam insulation we had before covering it, not sure if its worked yet, frost just started, but that one hydrant always froze and did not thaw til mid march or later.

showcrop · Jan 19, 2012

(quoted from post at 05:47:57 01/19/12) DIY Dave: I'll be using one length of plastic pipe going in to an adapter at the hydrant (2ft back on a galvanized pipe as advised before). the trickle is doable but don't really want to. Have to see.....

Showcrop: did you insulate the pipe itself or just do the sand and lay the foam on top? Styrofoam should be OK also?

I just laid the foam board over it. The idea is to allow the warmth from below to have access to the pipe but block the cold from above. I wouldn't use styrofoam. I don't think that the cell structure is the same, and I know that it is not as strong as the insulation board. Another note is that the same area is kept clear of snow all winter.

Anonymous-0 · Jan 20, 2012

Thanks!

NEBeef · Jan 20, 2012

Agree. Had the same problem a few years ago - big a$$ NE ledge where the water line had to go about 18" down. I figured that chunk of ledge could transfer enough heat from below so that a water line lying directly on top of it would never freeze, so that's what I did, cleaned up the ledge and layed the line right on it. Never had any problems with it even in some pretty severe no-snow, deep frost winters.

JDseller · Jan 20, 2012

Dave we have limestone bluff all around me here. Laying water lines is an adventure at times. What I have done many times is to put the water line inside of another larger pipe. The dead air acts as insulation and the inter pipe will not freeze.

The hydrant will drain so it will not be an issue. Just make sure and back fill with plenty of sand and it will not freeze there either.

frost depth???

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Member

Member

Well-known Member

Well-known Member

Well-known Member

Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Similar threads