# Spray Foam for Underground Piping



## strmh (Jun 20, 2008)

Called about 210' of 1 1/4" Thermopex today..........not cheap.

From what I've read, this is good stuff, but I really want to explore other options.

Several talk about laying pex, then having a contractor seal it in a spray foam.  I'm having a hard time getting my head around this process....will something like this work??:

-Dig trench to preferred depth

-lay 2" blue board in bottom (what about blue board on sides too??  Will this create a "form" for the foam?)

-run pex 

-Spray with urethane foam to seal

Am I on the right track?  Can anyone provide a name or link to a spray foam product that I can apply on my own?

Appreciate any help!!


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## heaterman (Jun 20, 2008)

strmh said:
			
		

> Called about 210' of 1 1/4" Thermopex today..........not cheap.
> 
> From what I've read, this is good stuff, but I really want to explore other options.
> 
> ...



The blue board could be done I suppose but as well as the spray stuff works, it would be kind of redundant and probably not a good ROI.

Check your yellow pages for insulating contractors and see what you come up with. You could also ask around at local lumberyards or homecenters to locate one. 

The process is pretty simple when you have the equipment these companies use. The guys that do our trenches have a truck with the diesel generator (to run the heaters) and about 500' of hose to spray the product. He simply walks along the trench using his foot to lift the foam while he sprays a "bed" 2-3" thick. After about 10 seconds the foam is hard enough to lay the tube back on it and spray over the top. The stuff is hard enough to walk on in about 2 minutes. As far a DIY kits go.I have no idea how they compare in cost but I know that I have seen them before in hardware stores and lumberyards.


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## Willman (Jun 20, 2008)

> Can anyone provide a name or link to a spray foam product that I can apply on my own


 heres one company with DIY foam kits. http://www.tigerfoam.com/  There are others. Also check out pour able foam might work with the foam forms.

Will


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## strmh (Jun 20, 2008)

Not sure I can find a contractor up here, but if I can, just ask for a "urethane foam"??  Also, can I assume that 3" to 4" surrounding the pipe is sufficient?

Do the pipes need to be wrapped in anything prior to insulating?

Thanks for the quick reply.


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## heaterman (Jun 20, 2008)

strmh said:
			
		

> Not sure I can find a contractor up here, but if I can, just ask for a "urethane foam"??  Also, can I assume that 3" to 4" surrounding the pipe is sufficient?
> 
> Do the pipes need to be wrapped in anything prior to insulating?
> 
> Thanks for the quick reply.



No the pex does not have to be wrapped.

3-4" is more than sufficient. When you look at a piece of Thermopex, Microflex, Logstor or any other brand, you'll see that the insulation is actually an inch or less on the sides. Foamed in place is the way to go.


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## Jim K in PA (Jun 20, 2008)

strmh - you can get kits online via www.foaminsulation.net  They are not cheap.  

I just called my local foam insulation guy and he was experienced in installing the foam in trenches for inulating pipe.  I am waiting on a quote, but he indicated something around $4/foot.  I am going to go this route.


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## sinnian (Jun 20, 2008)

I have read somewhere on these forums that the foam gets hotter when applied then the pex 180 degrees, so it should be applied in layers.


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## strmh (Jun 20, 2008)

The price of running 2 lines of 1 1/4" plus foaming is creeping up to the point that I may just go with the Thermopex........it pains me to spend that kind of coin on pipe, but I want it to be right, and I'm not sure this is a DIM (Do it Myself) project.  Overall, I can probably shave a little here and there on building construction to make up the extra $$ for Thermopex.

Thanks to all for the information provided


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## heaterman (Jun 21, 2008)

strmh said:
			
		

> The price of running 2 lines of 1 1/4" plus foaming is creeping up to the point that I may just go with the Thermopex........it pains me to spend that kind of coin on pipe, but I want it to be right, and I'm not sure this is a DIM (Do it Myself) project.  Overall, I can probably shave a little here and there on building construction to make up the extra $$ for Thermopex.
> 
> Thanks to all for the information provided



Just curious...............What are you paying for the Thermopex? What are you being quoted for 1-1/4" pex also, if you don't mind my asking?


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## strmh (Jun 21, 2008)

Quoted at $18.00 ft.


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## MrEd (Jun 21, 2008)

strmh said:
			
		

> Quoted at $18.00 ft.



Is that $18/foot, 1 1/4, oxygen barrier pex cut to any length? Where are you seeing that price. $18/foot isn't exactly cheap, but at pexsupply.com is closer to $30/foot. at $18 foot is doesn't seem quite so obscene.

http://www.pexsupply.com/product_dtl.asp?pID=7226&brand=Rovanco&cID=1053


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## strmh (Jun 21, 2008)

$18.00 ft cut to length.......


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## MrEd (Jun 21, 2008)

strmh said:
			
		

> $18.00 ft cut to length.......



Where?


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## heaterman (Jun 21, 2008)

strmh said:
			
		

> $18.00 ft cut to length.......



I'd be double checking to see exactly what I'm getting at that price. I've not run across anything even close to that. Not even direct from a manufacturer.


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## Jim K in PA (Jun 21, 2008)

I agree - $18.00/ft sounds real low for two pipe 1.25".  The best prices I am coming across for two pipe is around $26/ft., and that is at or near cost for Wirsbo/Uponor.  If that is the price they are giving you for single pipe, well, you know the rest . . .


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## ugenetoo (Jun 21, 2008)

strmh said:
			
		

> Not sure I can find a contractor up here, but if I can, just ask for a "urethane foam"??  Also, can I assume that 3" to 4" surrounding the pipe is sufficient?
> 
> Do the pipes need to be wrapped in anything prior to insulating?
> 
> Thanks for the quick reply.



check with the potato growers in northern maine. there are a couple of companies that do spray insulation for potato storages. i think there is also a company in brewer that does it.


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## strmh (Jun 22, 2008)

I'll double check on the price.......I'm fairly certain that was the per ft. price for the Thermopex.

Actually, I thought it was a pretty good price....but at 200 feet, it adds up.  

Thanks for all the input


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## Bob Rohr (Jun 22, 2008)

Gosh, maybe schedule 20 or 40 steel pipe threaded and foamed in the trench would be a better way.  Or galvanized if potential water is a concern.  I've seen plenty of pex melted off the back of OWF.  Never seen steel fail 

Dry is the key for underground piping.  Small amounts of water wick heat away rather quickly.

 hr


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