PEX vs Asphalt

aeclasik

Hey guys,



I'm a little curious about why PEX and asphalt don't really mix well together. I've been looking for any technical info on PEX embedded into asphalt. I've been reading a lot of threads here looking for why it is not recommended but haven't yet found anything substantially technical. I know the temperatures of asphalt will immediately destroy the PEX pipe, but is there any chemical problems with the PEX when it comes in contact with asphalt?



Thanks for any help

icesailor

PEX/Asphalt:

I have been told that water PEX, left out and stored on asphalt, will pick upi the odor of asphalt. Makes sense to me. I don't store it on an asphalt floor.

kcopp

Chemically...

your looking at oil predominanly. There were some case studies done (Wirsbo) where jet fuel was around and had no effect. As to the putting in asphalt... One guy did it and ran cold water through the tubing during the pour and for a day or two after to have it keep its shape.

Gordy

Pex vs asphalt

To start with asphalt when laid is 350*. The process when laying asphalt depending on area, and method results in loaded semi dumps, or six wheelers, pavers, and rollers on the pex . So I do not think it would take kindly to that type of traffic.



If I recall Mad Dog did his driveway with the pex in concrete then overplayed with asphalt. While a two step process for a driveway when one or the other on its own would work he was trying to take advantage of the sun on the driveway in the summer for domestic hot water, and snowmelt in the winter. If I remember correctly.



Gordy

Steve Whitbeck

pex

I have done snowmelt under pex - You install the pex in a thin layer of sand under the asphalt.  Earth/insulation/sand with PEX/asphalt.

works perfectly to this day.

Steve Whitbeck

Error

I meant to say PEX under asphault.

aeclasik

PEX Life

What would exactly happen if the asphalt touched the PEX? Would the asphalt start to break down the the PEX barrier and then the PEX pipe itself? How long would you guys say the PEX would last if installed? I know most PEX companies allow their product to be installed in asphalt, but is there a way to quantify the duration?

Canuck_3

Kitec Spec

I've attached an old spec from Kitec, which listed their procedure for installing in asphalt. I'd be chewing my nails having to do this, but, I guess it was done.

RobG

Pex And Asphalt

I did my own driveway under asphalt the same way Steve did. The only thing Steve left out of his disciption was running cold water through the tubing during the asphalt laying. I used Uponor He-pex, stapled to the insulation, a layer of sand (moistened and tamped), then kept a close eye on the asphalt installers. 

I did this in summer of 2002. worked great to this day.

Rob