# Inject a wall with Great Stuff?



## gunner666 (Jul 16, 2014)

Have this PITA bathroom. Tenants thought they were paying too much for heat in the winter. Code person verified that it needed to be like 3 degrees warmer with the heat off. Has a crawlspace under it. No air leaks and no moisture (no moisture so fiberglass is okay and thus doesn't require foam board that isn't affected by moisture like fiberglass), and crawlspace is open to the warm basement (like 5 boilers in basement) and feels warm in coldest times. I insulated the walls of crawlspace with R30 fiberglass doubled up to R60 in some places. Then, in bathroom, I cut holes in every wall bay and rented cellulose insulation blower. It kept clogging and would not fill bays. So I reached into holes and stuffed fiberglass as far as I could reach. Patched and painted and it made it at least 3 degrees warmer. 
The next winter, the shower line freezes. I didn't original insulate behind the shower because I didn't remove tiles. Wrapped the shower line in the crawlspace with electric heater tape. It almost froze again still with that. 

The problem is loss of heat behind the shower walls. I'm trying to find a foam injection contractor to do only the shower from the outside. I will remove the wood clap boards and drill through the sheathing (if the house even has plywood) or try to remove tiles without breaking them. But I might not find someone in time to do such a small job and for not a huge cost to justify the small job. Can't I just drill holes either in the outside of though the tiles (or press my luck and see if the tiles will remove unbroken or hopefully find a good enough match to replace tiles) and then just get a whole bunch of cans of Great Stuff Large Gap filler? I would drill 1/4" holes for the great stuff straw starting at the floor and then I guess another hole every foot or so up the wall and work my way up with the foam. Should be fine, right?


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## Windows on Wash (Aug 30, 2011)

No.

Not unless you want to bow the wall. 

You need a confined space foam. Look for an AirKrete contractor if you can. 

If you have attic access, you can probably drill the top plate and drop it down that way.


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## joecaption (Nov 30, 2011)

OK so where is this place?
Plumbing on an outside wall in anyplace that freazes is a huge mistake.
No way do you want to be drilling tiles!!!
Did you air seal under the house and in the attic?


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## gunner666 (Jul 16, 2014)

well I guess I might have get that spray it green stuff if great stuff will buckle the wall and break the tile.https://www.sprayfoamkit.com/spray-foam-insulation/spray-foam-insulation-value.html


Lowest price I got so far from a spray injection contractor was $1,200 just for only about 8 stud bays, and I said I'll have all the holes drilled and everything, all they have to do is spray and go. 
Good point about why is the plumbing even on an exterior wall. Come to think of it, I don't think I've ever seen that. Asking for trouble like this, and the people who build this bathroom were complete hacks. The walls aren't even fully insulated I found when I opened the drywall to blow in cellulose. And the bathroom sits on a crawlspace that 1/4 of the crawlspace is open to decking boards on a patio. The bathroom is basically added onto a deck. I sealed off the section of crawlspace where the ceiling was the decking. I used foam insulation boards and sealant all around and double R30 fiberglass. It's a two or three apt building/house that they later converted into like 4 apts and thus hacked this bathroom in there like this. 


Another option is rip out all the shower tile walls and put fiberglass batts (on the side of the pipes that faces outside so the heat from the bathroom actually flows through the pipes but is then halted by the fiberglass instead of sandwiching the pipes with fiberglass on both sides which will halt the heat from ever reaching the pipe to keep it from freezing. And then just put plastic shower panel board up that looks like tiles. But I don't know how to do that. Just cut to size and caulk the seams and needs cement backer or what kind of backer board behind the plastic shower panel walls?


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## oh'mike (Sep 18, 2009)

Bad job --is there any way to move the plumbing to an inside wall?


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## Colbyt (Jan 27, 2014)

You don't mention your location or skill level. I also can not see the house configuration.

For 8 stud bays, I would remove the exterior siding, insulate the pipes with foam, self sealing sleeves, insulate the bays with fiberglass and if it would not interfere with the exterior finish I would add a 3/4" layer insulation board. I would tape all seams on that board.

That's a lot of labor, but not a lot of material cost.


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## gunner666 (Jul 16, 2014)

I'm probably going to end up removing all the siding and the plywood (if it even has it) and then putting in insulation from outside. What kind of home wrap should I use since I'll have to rip off what's there? Tyvek or felt paper?? And what caulk should I use on the terminations of said house wrap to seal where it meets the vertical seam of the existing?


I can't use foam boards over the outside because it will bump the wall out and needs to match the rest of the building. If there's no sheathing, I don't think I can add it because again, it won't match the rest of the building, so would I need a special type of house wrap in that case?

If I use tyvek which probably restricts more air flow than felt, do I even need to use air tight foam insulation boards in the walls (and caulked around perimeter) or can I just use fiberglass? Because fiberglass has so much more insulating power than foam, or should I just use both plus wrap the copper pipes in black foam pipe wrap insulation but make sure not to compress the fiberglass?


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## Colbyt (Jan 27, 2014)

I would use the black foam pipe wrap on the pipes. I would turn the seam toward the heated side. Since I'm obsessive I would add a few wraps of duct tape also. I would use fiberglass batts with the facing toward the room side.

I would try hard to get a layer of foam in there, even if I to cut it to fit within the cavity and yes that will compress the fiberglass by .5"; no big deal.

Taped house wrap may be the better choice in this case. In most parts of the US the felt is just as good as the wrap _for moisture penetration._


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## gunner666 (Jul 16, 2014)

If I do this, I'm taking the tile shower walls off. Need some advice on what kind of vinyl panels to install on the studs after taking the tiles off. I posted new in bathroom section thanks
http://www.diychatroom.com/f80/viny...e-glue-studs-caulk-joints-293817/#post2266561


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## 6273909 (Nov 15, 2012)

Just a crazy idea but could you pipe a little heat into the wall cavity? It wouldn't be ideal but it would be cheap and easy. Just a small pvc pipe from the duct work into the cavity.


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## Colbyt (Jan 27, 2014)

6273909 said:


> Just a crazy idea but could you pipe a little heat into the wall cavity? It wouldn't be ideal but it would be cheap and easy. Just a small pvc pipe from the duct work into the cavity.



That shows you are thinking outside the box and that is good, but it is not a good plan. Chances are it would create moisture inside the wall when warm meets cold. That probably would lead to mold or rot.


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