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Barry Wallett Posted: Feb 13, 2007 02:11 PM	Any experience with foam bending pipes Ok guys, I am bidding out the various subs on my new house, a plumber tells me that he has had experience with foam getting behind his pipes when it is applied and pushing the pipes away from the wall. He stated foam is fine but on two occasions this problem has occurred. What is the real deal? Thanks
Posted: Feb 13, 2007 10:00 PM	barry,,,i have seen it bow long vent runs of pvc type pipe in stud cavities as these typically arent secured very well since they only carry air....most plumbing runs are either short,,or secured with a strap clamp or other device when it is a long run if it is a good installed... i now look for these 8' long unsecure pvc pipe runs when "prepping" the place out and will tack a scrap 2x4 or the like across the mid stud to keep the pipe behind the stud face... tell the plumber that :yes the pipes could be pushed by foam if they are not secured properly at the time of their installation,,,and that as an experienced foamer you have learned to identify these potential problem area's, as well as others,,, and will modify your application technique to accomodate the precarious installation to prevent undesireable results,,, use this a marketing tool... "that is why we should do the work,,,we pay attention to the detail,,work as part of a team...have the knowledge and skills to accomodate..." you can not "hammer on" a closed cell around plumbing,elect or other boxes or any other attached device,,,,look at ALL of these in the structure as potential problems and slow build around these...the ounce of prevention is worth a pound of cure...(remember these above mentioned fixtures were installed by plumbers, electricians and carpenter's... :) ).....
Gerry Wagoner Posted: Feb 13, 2007 10:14 PM	Don't know. Depends on some variables. What you can do is spray a dab on the pipes in several places to cement them in place. I don't think pipe "pushing" is a big problem or else I would have encountered it before. Never had it. Have fun, olger
SprayFoamSupply.com Posted: Feb 14, 2007 06:19 AM	It is possible to push out the pipes where a drain line comes straight down a wall from the second floor to the basement. It is usually an 8' length with no bracing. If it is on an extrior wall, you are trying to foam behind it and it easily bends in the middle and can easily be pushed out past the studs near the middle as it offers little resistence. I push it in with my hand as I spray around it. George
Melvin Chandler Posted: Feb 16, 2007 08:05 AM	We've had this happen with the coiled dryer vents that people use for bathroom vents. Some have been in the roof/ceiling joists where the drywall is secured directly to the roof/ceiling joist. We tried to strap to hold in but because the line is so flexible and the 4" line was in a 6" cavity, it was nearly impossible to keep from pushing out. Plus, the temp of the foam & exotherm nearly melted the plastic so when we tried to move after spraying, it just tore. Owner was a bit upset because now he had breaks in his line and said that he would eventually have moisture problems where the lines were spliced. I asked if he really thought the dryer vents would last forever or if he had planned to remove and replace every 5-10 years. He appeared stunned and said asked what I was talking about so I asked how often he typically changes his actual dryer vents. I saw the light come on. Then I pointed out that he had 3 pipes and all had a max length of about 8'. How much more expensive would it have been to use a solid pipe? We talked about chemical temps and exotherm prior to the installation and he knew that the plastic coiled vents were somewhat temp sensative. It's my experience that the owners and contractors hear what they want to hear. I can only plan and think for them so much. They've got to take the wheel at some point.

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Barry Wallett

Posted: Feb 13, 2007 02:11 PM

Any experience with foam bending pipes

Ok guys,

I am bidding out the various subs on my new house, a plumber tells me that he has had experience with foam getting behind his pipes when it is applied and pushing the pipes away from the wall. He stated foam is fine but on two occasions this problem has occurred.

What is the real deal?

Thanks

Posted: Feb 13, 2007 10:00 PM

barry,,,i have seen it bow long vent runs of pvc type pipe in stud cavities as these typically arent secured very well since they only carry air....most plumbing runs are either short,,or secured with a strap clamp or other device when it is a long run if it is a good installed...

i now look for these 8' long unsecure pvc pipe runs when "prepping" the place out and will tack a scrap 2x4 or the like across the mid stud to keep the pipe behind the stud face...

tell the plumber that :yes the pipes could be pushed by foam if they are not secured properly at the time of their installation,,,and that as an experienced foamer you have learned to identify these potential problem area's, as well as others,,, and will modify your application technique to accomodate the precarious installation to prevent undesireable results,,,

use this a marketing tool...
"that is why we should do the work,,,we pay attention to the detail,,work as part of a team...have the knowledge and skills to accomodate..."

you can not "hammer on" a closed cell around plumbing,elect or other boxes or any other attached device,,,,look at ALL of these in the structure as potential problems and slow build around these...the ounce of prevention is worth a pound of cure...(remember these above mentioned fixtures were installed by plumbers, electricians and carpenter's... :) ).....

Gerry Wagoner

Posted: Feb 13, 2007 10:14 PM

Don't know. Depends on some variables.

What you can do is spray a dab on the pipes in several places to cement them in place. I don't think pipe "pushing" is a big problem or else I would have encountered it before. Never had it.

Have fun,

olger

SprayFoamSupply.com

Posted: Feb 14, 2007 06:19 AM

It is possible to push out the pipes where a drain line comes straight down a wall from the second floor to the basement. It is usually an 8' length with no bracing. If it is on an extrior wall, you are trying to foam behind it and it easily bends in the middle and can easily be pushed out past the studs near the middle as it offers little resistence. I push it in with my hand as I spray around it.

George

Melvin Chandler

Posted: Feb 16, 2007 08:05 AM

We've had this happen with the coiled dryer vents that people use for bathroom vents. Some have been in the roof/ceiling joists where the drywall is secured directly to the roof/ceiling joist. We tried to strap to hold in but because the line is so flexible and the 4" line was in a 6" cavity, it was nearly impossible to keep from pushing out. Plus, the temp of the foam & exotherm nearly melted the plastic so when we tried to move after spraying, it just tore. Owner was a bit upset because now he had breaks in his line and said that he would eventually have moisture problems where the lines were spliced. I asked if he really thought the dryer vents would last forever or if he had planned to remove and replace every 5-10 years. He appeared stunned and said asked what I was talking about so I asked how often he typically changes his actual dryer vents. I saw the light come on. Then I pointed out that he had 3 pipes and all had a max length of about 8'. How much more expensive would it have been to use a solid pipe? We talked about chemical temps and exotherm prior to the installation and he knew that the plastic coiled vents were somewhat temp sensative. It's my experience that the owners and contractors hear what they want to hear. I can only plan and think for them so much. They've got to take the wheel at some point.

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