Inject a wall with Great Stuff?


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Old 07-14-15, 01:27 PM
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Inject a wall with Great Stuff?

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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Old 07-14-15, 01:35 PM
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The problem will be if he did a complete job of insulating it. You/he won't be able to see the results. Insulation does not create heat. If there is no heat in the walls, cold will prevail. Great stuff will expand, and you don't want that. They make a minimally expanding product, so if you decide to do this, use that. I am not recommending you do this. Removal of the clapboard is half the job done. Expose the entire piping system and deal with it with the wall open.
 
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Old 07-14-15, 02:13 PM
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The problem will be if he did a complete job of insulating it. You/he won't be able to see the results. Insulation does not create heat. If there is no heat in the walls, cold will prevail. Great stuff will expand, and you don't want that. They make a minimally expanding product, so if you decide to do this, use that. I am not recommending you do this. Removal of the clapboard is half the job done. Expose the entire piping system and deal with it with the wall open.

Why is it a problem if the foam encapsulates the pipes and wires in wall if they're not leaking? Even if they ever do, the whole wall would have to be opened anyway and the foam/great stuff should peel right off it for the most part to repair. The pipe froze but didn't break, not leaking because it would leak down into the crawlspace (the sill plate in the crawlspace to the wall bay with the shower line was done pretty bad, they jackhammered the block wall and there's a few inches space gap that I insulated up into but could only reach a foot or so up stuffing insulation. The heat is in the bathroom/apt and is being lost though the walls.

Why would I use the low-expanding windows/doors version and not the large gap kind? Great stuff won't break or shift the tile wall or pipes or anything.
 
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Old 07-14-15, 02:37 PM
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Foam it Green DIY Spray Foam Insulation Kits

They sell a slow rise foam for injecting into closed walls. It should be a lot cheaper than using Great Stuff. You don't want a fast expanding foam like Great Stuff large gap because it will push the drywall off of the studs as it expands.

Encasing the plumbing and wiring is not a problem.
 
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Old 07-14-15, 05:03 PM
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Why is it a problem
I didn't say there would be a problem if you encapsulated the pipes and wires. I said the problem would be if you DIDN'T get it all covered. How would you know, if only small holes were drilled? Foam won't just "peel" off stuff as you say, It is horribly adhesive. Andrew told you why about the expanding foam pushing out on the walls, and it will. It will break tile and anything else in its way.
 
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Old 07-14-15, 05:33 PM
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Listen to Droo and Chandler. The high expanding stuff will not flow as quickly or easily as you might think. It will setup very close to where it is injected. Also the heat question is still there. That wall will need to get some kind of heat. Otherwise it will just adjust to the outside temp and still freeze.
 
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Old 07-14-15, 05:50 PM
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You don't want a fast expanding foam like Great Stuff large gap because it will push the drywall off of the studs as it expands.
I can tell you.... I have witnessed that first hand. What a mess to repair.
 
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Old 07-14-15, 06:03 PM
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I would not be concerned about the foam covering the pipes. The pipes are going to be closer to the warm side of the wall. Heat will get to them before the cold from the outside will. They aren't going to freeze.
 
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Old 07-14-15, 08:12 PM
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well I guess I might have get that spray it green stuff if great stuff will buckle the wall and break the tile. 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.

I've pulled great stuff off a vinyl window, granted it's vinyl and not very adhesive surface but it came right off but left a residue. Not worried about it sticking to pipes though because the pipes aren't broke. Another forum made a 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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Old 07-15-15, 03:34 AM
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You are making this too hard. You said you could remove the clapboard in post #1. If you can to that, you can remove the osb as well, insulate the cavity properly, replace the OSB and clapboard. What am I missing?
 
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Old 07-15-15, 12:16 PM
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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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Old 07-15-15, 12:34 PM
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The tyvek should be fine.
"Because fiberglass has so much more insulating power than foam" actually fiberglass has less r-value per inch than foam and it also allows more air movement.

One of the key objectives where you are trying to prevent those pipes from freezing is to insulate between the pipes and the cold, but not insulate between the pipes and their source of heat, the inside. Where the inside is a shower it may not be the best source of heat, but surrounding the pipes in insulation would mean they must conduct heat from some distance away. Use the rigid insulation between the pipes and the outside and seal the rigid and any place where cold air can get into that cavity. If your pipes exit the bottom of that cavity, be sure the same approach is used anywhere the pipes are close to the cold exterior.

Another rule is to air seal. The house wrap is a water barrier that allows moisture vapor to pass thus allowing drying to the outside. But it is often full of holes where attached. Tape it good and seal out the cold air.

Bud
 
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Old 07-15-15, 07:15 PM
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If I do this, I'm taking the tile shower walls off, then hopefully just gluing vinyl shower panels to the studs. Not sure about this though and made new thread in bathroom section. thanks.
http://www.doityourself.com/forum/de...ml#post2439035
 
 

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