# injecting foam for freezing pipe in wall



## SeniorSitizen (Sep 10, 2012)

When you wrapped the pipes in the 75° crawl you insulated the 75° air from the pipes. Counter productive. Any insulation you place in the wall needs to be between the clap boards and the pipes.


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## gunner666 (Jul 16, 2014)

^ yes very good observation. I did notice this yesterday.
Makes you think, when insulating a wall that has pipes and keeping them from freezing is the main concern besides general heat loss in winter or AC loss in Summer, why even insulate the half of the cavity in front of the pipes facing the wall? counter productive because heat is lost always because heat moves from hot to cold area, so if you skip the insulation in the front half of the wall cavity that faces the inside, then the interior heat will be full force as it passes through the pipes and then will retard when it hits the insulation between the sheathing and the pipes. Like you pointed out, the heat will retard before it hits the pipes if both 'halves' of the wall cavity in front and behind the pipes is insulated.
Usually it's not a concern and the whole thing is insulated because it will maintain more heat inside of the building or keep more AC inside the building. 


I don't think unwrapping the pipes in the crawlspace will make much difference though, even if I wrap the crawlspace section with electronic heated pipe wrap, I don't think the heat will transfer all the way up the 8 foot wall to where it is freezing.


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## SeniorSitizen (Sep 10, 2012)

_If you electric heat trace the pipes or allow a small stream of water to run to prevent freezing you've changed to a different heat source and now those pipes will benefit from being encapsulated with insulation. The ambient air is no longer the source of heat._


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## gunner666 (Jul 16, 2014)

I think the ambient air is warmer than the cold water though if it were left at a trickle, so I think it would be better to keep them uninsulated in that case but not if wrapped with the electric heater wire (if it's even safe to wrap over than with fiberglass).


Here's what I'm pretty sure is going to happen: Instead of taking the whole siding clap board section off and probably having a few crack no matter how gently, I think we'll just drill hole saw right through the clap board and inject the foam through there and then plug the holes and put a bunch of paint layers over to hide the plugs 

The slow leak in the plumbing might just have to be for now. Because the only way to address that is to remove all the exterior siding and then cut away a section of sheathing (if even installed) and then fix the pipe from there or from inside by taking the tile wall down. Most likely it would be done from outside and would be a race against the freeezing to get the wall put back together after the plumber fixes the pipe. If done inside, there'll be no shower and thus possibly pay loss deductions or something from the tenants. Fixing the pipe can be done after the foam, just the bay with the burst pipe, if it ever bursts, the foam insulation will have to be picked out of there and then reinsulated after the pipe's fixed. 

*Where can I even get the injection foam?* Online or have to have to be certified and buy a big truck load at a time? Because all I think really needs it is the bay with the frozen pipe and the two surrounding bays which I can do no problem, and to get an injection contractor for just that small job, they'll probably charge for the day and this is on a budget. But if they do charge for the day, there's at least 8 other bays they can do on the other side of the shower around the corner of the wall even though the bathroom already meets temperature code, the shower walls have possibly zero insulation in them so it's good to be safe and insulate those as well.


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## gunner666 (Jul 16, 2014)

the crawlspace under the bathroom was 40 Fahrenheit while outside was 15. So, the fiberglass on the crawlspace ceiling is only making the bathroom colder, correct? Because ceiling insualtion is stopping the hot crawlspace air from rising though the bathroom floor, yea? Also as I mentioned in the first wall of text, in the crawlspace, if you look up in the corner you can see up in the bay where the copper pipes go to the shower, the same pipes that are freezing. I should remove the fiberglass insulation plug that is there also, right? And then try and fish insulation up the 8 foot wall bay but only on the side of the pipe that faces the outside, yea?
I wish I could get foam board up there but it's like a 3' crawlspace so I think the only option is to fish a small piece of fiberglass up at a time with a telescopic stick or something until the whole thing is filled with fiberglass but not compressed fiberglass which lowers it's R value.
Maybe this will be enough to keep the pipe from freezing and also make the bathroom warmer.


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## gunner666 (Jul 16, 2014)

One last thing.. hopefully, if someone ever finds themselves in this same situation where the original builders just skipped insulating the bathroom and shower, and if you don't want to pay for an injection foam company or buy the DIY kits but want to insulate the walls behind the shower and possibly fix a slow leak, then instead of taking the whole exterior off, knock the tile shower walls off, fix the pipe, insulate with foam boards and caulk the perimeter (possibly only insulating the half of the stud bay which is between the pipes and the exterior wall so that the hot air from the bathroom passes through the pipes hotter than if the half of the stud cavity between the drywall and the copper were also insulated), and then instead of having to retile, just get one of those plastic bathfitter type solid plastic walls, maintenance-free easy to clean etc. You can install a fancy marble counter or something to counter balance it if you think the plastic tiles look cheap or something but I think they're great.


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## gunner666 (Jul 16, 2014)

well one more note, sort of talking to myself in this thread, but in case it helps anyone: 



Always check the obvious. After all this, I just remembered seeing broken glass outside this bathroom's window last year. I'm pretty sure they just replaced only the glass with plexiglass after it broke, and this is one of those double pane windows with the sealed insulating gas in between the panes. Of course just putting a regular piece of glass into it will greatly reduce the temperature. This could be the main culprit. 

Tonight, I went to try and stick insulation up into the bay where the frozen pipe was (because you can actually see up the bay from the crawlspace...). I forgot I already stuffed the bay with fiberglass last year. The bay is also already insulated with batts but it's very drafty and is like a 2x6 stud with 2x4 sized batts so there's a lot of dead space that could be insulated. I pulled the insulation out because having it on the side of the pipe that faces towards the warm bathroom is only slowing the transfer of heat from the bathroom into the pipes, you only want the colder side of the pipes insulated (of course this and some of the other methods described are only good for maximizing heat and will lower the insulating affect when trying to keep cool in the building in summer).




I also discovered the slow leak is likely just the trap from the shower PVC and probably easily fixed from the crawlspace, so that's good.



The crawlspace was supposedly 25 degrees F while it was 9 degrees outside. I checked and it was 59 while 36 outside. Which isn't as warm as I thought it would be, so I didn't remove all the insulation from the crawlspace ceiling to allow the crawlspace's hot air to rise and help heat up the bathroom, instead, the insulation will stay there and slow the transfer of the bathroom heat being lost to the colder crawlspace. The only part I left open was the bay that can be looked up into from the crawlspace which has the frozen pipe. Because it's better that the warm air of the crawlspace can go up in that bay instead of it being blocked by insulation. Because heat always migrates towards cold, so if it were insulated, it wouldn't do any good because that stud bay is colder than the crawlspace. 



the only options I see left are remove the r30 fiberglass from the walls and spray insulation on them and the rim joists. I have never installed anything but fiberglass in many inspected basements finished but I think there's some draft coming through the fiberglass even though I caulked every crevice. Maybe plastic sheet can be put over the cement and then caulked all along the perimeter to stop draft but the crawlspace is so dam small with so many obstacles that it would make sense to just shoot everything with foam, even if it's that $400 foam it green kit you buy in the mail or something. The foundation walls are so bumpy and stuff that foam boards would have big gaps behind them and might not be able to seal and caulk the perimeter backing so I would say just shoot foam instead of that too. And then put the r30 back over the foam because it has so much more R value than the foam. Or maybe there's something you can shoot on with a compressor that just seals everything but has no insulating value but then install the fiberglass over that. 

but the main problem is the drafty bathroom walls and of course the broken window. The only way to address that is with the injection foam I already mentioned or to take the whole tile wall down from inside and use non-injected foam boards and then replace the tiles with a plastic shower wall just because it's a lot easier and less problematic than redoing the tiles. 

can also wrap the pipe in the crawlspace with a plug-in water pipe heater.
Maybe you can gain a few degrees by using some special exterior paint on the wood clap boards but it's probably just a waste of money that can go towards injection foam.

There's a small baseboard hot water heater in the bathroom this whole time. that should be inspected to make sure it's working right.


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