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[merrellroofing]

Anyone with experience or opinions on Spray-foaming the trench as opposed to Thermo-Pex for $11 a ft.?
I will have about 150 ft. run coming out of a metal roof barn, under the gravel driveway then to the house.

[Scott7m]

Anyone with experience or opinions on Spray-foaming the trench as opposed to Thermo-Pex for $11 a ft.?
I will have about 150 ft. run coming out of a metal roof barn, under the gravel driveway then to the house.

I've seen it done..  I just dont know.  I think that paying 11 bucks a foot for thermo pex is a bit high.  I've seen test done with standard prodex style triple wrap where the water leaves the stove at 180, and 100 feet later its 179.  Soooo for 6 bucks more a foot, how much better are you really going to do? 

Another example, last winter the ground was frozen so thick here that i could only do installs where i laid the line on top of the ground.  On numerous jobs I'd fire the stove up and come back the following day and the "basic triple wrap" pipe would be laying there with snow all over it.  NOT MELTING!!   So once again, how much better are you going to get? 

The line i use is eze-Flex Silver triple wrap, its made in MI.    I also have sold a bit of thermopex, I cant say that I could tell a difference, I sell it for 9 bucks a foot and triple wrap for 6. 

[willieG]

my only concern witht he tripple wrap (if it what i think it is...pipe wrapped in bubble wrap and slid in a plastic tile) if a stone rubs a hole in the tile or if it cracks for some reason and lets water in the tube...all insulation value is gone. i think the foam will repel the water (if it is the right foam) if the covering on it is penetrated. Could be wrong and if i am we will hear about it and if the bubble wrap tube is penetrated and water gets in, you will see it quickly,,no frost above pipe all winter

[RSI]

If it is buried correctly there is no problem. Also, there would have to be ground water at the pipe for it to fill.

[willieG]

If it is buried correctly there is no problem. Also, there would have to be ground water at the pipe for it to fill.

in my part of ontario canada if you have a pocket of anykind 2 or 3 feet below ground and you get one of them all day rains that brings and inch or two..that pocket will be full of water. if you had a hole in your tile, your bubble wrap would be floating in the said tile and your insulation value would be zero. i have no way of knowing if it was installed properly what the life span would be or if it would ever leak, i was just pointing out that if water "somehow" got in that tile your insulation value would go down dramatically.

[RSI]

The triple wrap mentioned above is not bubble wrap. It is 1/4" layers of closed cell foam with foil on them. If the drain tile had water in it it would reduce the insulation value but it would still be way above zero. You could also but in in a larger drain tile if you are worried about it. There isn't much chance both layers would get damaged.

If you foam the trench, What happens when the ground shifts from frost? Will the foam in the trench crack?

[willieG]

i have no idea and i dis say i was guessing at if the stuff mentioned was bubble wrap. as for if the foam in the trench cracked i would guess that it would also lose some insulation value. i am not here to say what is best and what is not, just to give opinions as everyone else. i can say from experience that when installed my pipe it was some kind of plastic bubble wrap with a thin layer of fiberglass glued to it and wrapped around the return line twice and the feed line three times and shoved insidea 4 inch 1/8th thick plastic sewer pipe. (thats what it looked like anyway) this pipe was buried in sand and lasted about 9 years before the ground no longer froze over top of it. how the water got in i am not sure as when i dug it up i ruined the plastic pipe in many spots. When i installed this pipe it was about 6 bucks a foot, this time i installed the logstor stuff at (in my area) 12 bucks a foot so now i have 18 bucks a foot in the pipe over the time period of (now 11 years) so i would suggest that anyone installing this pipe to dig deep for extensive information on all the brands you think you may be interested in.the price you are about to pay for underground pipe is the price you want to pay for life, you don't want to have to replace it like i did. i am sure there are better pipes being made and the choices may be many. All i say is choose carefully!

[RSI]

Do you happen to have any pictures of the old stuff?
They used to use recycled plastic outer pipe and it breaks down after time. I wonder if that might be what happened? Most now use 100% new plastic only.

[willieG]

i never took pictures of the old stuff but it looked like white sewer pipe with glued joints every 12 feet or so. It was what was used pretty much by all the dealers around my area at that time. then a few years later some other stuff started showing up like the same outer pipe but some kind of white foam material for around the pipes themselves..then colored foam inside what looked like farm tile and then the logstor stuff that was like spray foam inside a rubberized looking outer layer. i have no proof of what is best and i hesitate to tell anyone what to buy but my personal preference would be the logstor type stuff. i am sure there must be many names for basically the same stuff and there likely is better stuff available. like i said in my other post...learn all you can and make an informed choice. the pipe you buy is a very important part of your heating system. there were even some guys foaming the trench but at that time it was not closed cell foam and the foam took on water as time passed and was no better than my bubble wrap. one fellow dug his up and said he could not lift a 12 foot section of the foamed pipe because the foam had taken on so much water!

[RSI]

That doesn't surprise me it filled with water with all those splices.

Back to the original topic, foaming the trench under a driveway sounds like it would get crushed.

If you do end up doing it, I would use pour in marine foam. It is cheaper and made for wet locations.

[merrellroofing]

What is the marine foam?

Onto the next thing-How deep?
Some people say 18-24 inches is plenty.  Stay above ground water
Some say go deeper below frost.
I know I will have to go deeper about 40 ft. to cross the driveway but the rest of the way I will be concreting over it, therefore I do not want to dig it back up.

[Bull]

I would stay below the frost line in your area.

[Ridgekid]

To follow up with what WillieG was describing (Correct me if I'm wrong) I've attached the following link:

http://www.centralboiler.com/Tech/C080.pdf

I installed the stuff on the left side (Thermo pex). It has a neoprene core. Less likely to absorb water, but a Bear to install because of it's stiffness. I went down 18" to the top of the pipe and covered with sand first, before backfilling.

[willieG]

What is the marine foam?

Onto the next thing-How deep?
Some people say 18-24 inches is plenty.  Stay above ground water
Some say go deeper below frost.
I know I will have to go deeper about 40 ft. to cross the driveway but the rest of the way I will be concreting over it, therefore I do not want to dig it back up.

i would consider (at least) where you are putting concrete over it to run it through a larger farm type tile just in case you ever have to pull it up for some reason. i ran mine in a 12 inch steel pipe under my garage floor...just in case

[RSI]

What is the marine foam?

Here is one brand http://www.uscomposites.com/foam.html