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[TheCrier]

Hello everyone,

Building a new 30' x 54' two story shop and studio.... and had my 1.5" pex lines insulated and backfilled today. I insulated with 1/2" rubber foam then sprayed with soy based 3lbs spray foam to R36. This evening I found this site and was reading here that the lines shouldn't be spray foamed and that it will eventually become saturated with ground water. I was assured by the company who sprays this all the time that it will NOT absorb water and he waterproof with this product all the time. The installer seemed to know what he was doing.

What's up. Waste of money?

[willieG]

i have no idea...i have questioned this method but most seem to say if you use the proper foam you should be good

[MattyNH]

Seems like a good idea..I know spray insulation is not cheap..My only question is how long will it last in the ground before it starts breaking down and or the R value goes down..Id say they only way it takes on water if a area is missed or you have a pin hole somewhere or when it starts to break down over time..

[willieG]

to have any chance at all it must be closed cell foam (and i have been told this is never going to take on water but i personally have my doubts) i do know the open cell foam will suck up water

[TheCrier]

Up here in Alberta the spray foam application has been used for years in the oil and gas industry. I've seen excavated 12" high pressure gas line below water table in muskeg areas look like new after 10 years. That's what gave me the idea to spray my hydronic lines. The new soy/plastic application is far more superior than what was used before 2005. I paid $2300 for for about 300' of lines and my walls and ceiling of my 8'x 12' cold room. (two trips)

Mind you, that was my price.

[TheCrier]

Here is the cold room sprayed out with 5.5 inches of the same product.

I will install 1/2" recycled rubber floor tiles to stop heat transfer from the in floor heat next to my cold room.

[juddspaintballs]

I will be spray foaming my lines in place.  I'll also be somewhat wrapping them in plastic after the foam.  My plan is to dig the trench, lay a continuous run of plastic sheeting in it, lay the PEX in, spray foam it in place but lifted off of the bottom a couple inches, and then wrap the final foamed product with the remaining plastic and back fill the trench.  I don't think the foam will ever get water logged.  The plastic is to keep clods of dirt from accidentally being sprayed in with the foam and causing a weak point in the foam.

[willieG]

for what it is worth boys and girls here is all i can find on the two types of foam commonly used...open cell foam is used in walls in a home basically because it will "move" with the home and not break away from the studs it has a less R value than closed cell
it will uptake water but it will also drain and dry out if not under the water (not good for underground)

closed cell foam  has a higher R value, it is considered a vapour barrier but should not be used where any movement occurs, it will not "move" with the studs of your home but will crack and seperate letting  cold and moisture in

With that info i think i will go with a pipe with the closed cell foam inside a plastic tile. and i think i will also run that down another water tight plastic tile (non perforated) if i am gonnna spend the buck on the pipe i am gonna put another waterproof jacket around it

[willieG]

and if you look further you will find info that says closed cell does move and wont crack...sheesh. how do those sales guys do it...i think they must all be lying or really (like me) just don't know

i'm still gonna put another tile around it!

[willieG]

quote from a boat manufacturer
"Is this foam water resistant?

"Yes, but with the following caveat. The foams that we sell are considered closed-cell, which means that each cell that makes up the foam structure is completely closed off from surrounding cells which prevents it from acting like a sponge. It is completely safe for this foam to be in contact with water for hours/days/weeks and even months with no adverse effects. However, it should never be submerged in contact with water permanently. Over a period of years the water contact can begin to soften the foam and cause it to lose its closed-cell status. This foam is designed primarily to be used as an insurance policy in case of damage/holes that could cause a vessel to lose buoyancy. Pinhole sized openings would essentially have no effect on the foam since the amount of exposure is so minimal but you should always make repairs as soon as possible to keep the foam effectiveness as good as possible. This will be the case will all after market closed-cell polyurethane foams and even manufacturer installed foams."

would you consider underground being submerged or not..i guess that is the question?

Thats it I'm done..there is too much info and i may go all the way over the insanity line if i keep looking

[Scott7m]

willie, i'm not sure

I mean unless you have soil that is practically a muck and full of water year around I dont know.  I dug a couple trenches today and the ground here is usually fairly dry, of course in the winter/spring its wet but I wouldnt' call it submerged by any means.

If i were going to do the spray foam lines I sure wouldn't hire someone to do it.  I would just order a tiger foam closed cell kit and do it myself.  they sell a kit thats around 600 dollars and it does a great job.

[TheCrier]

Hey Willie, investigate soy based insul spray. Soy veggie oil mixed with some kind of plastic chemical concoction. Very minimal flex but in my opinion no need to wrap it in anything else, although I suppose it wouldn't hurt.

Last night we got 3" of heavy snow and I ran straight out to my freshly buried lines, then straight to my gauges.

A .3 diiffernce in temperature from my boiler to the heat exchanger at my furnace.

   

[Scott7m]

thats good......   where in the world do you live getting 3"of snow already?

[TheCrier]

thats good......   where in the world do you live getting 3"of snow already?

I'm in Bragg Creek Alberta, on the side of Banded Peak mountain. Suppose to snow again tonight but won't stay.

[Scott7m]

Wow....    thats far north for sure..   If you have any big whitetails that need hunted just let me know!!! hahaa