Spray Foaming Bathroom - Wiring and Plumbing Flexibility?

Thought I'd pick the GRM hive mind on this one as the group's construction advice is usually diverse and extensive. I think I've asked about it before, too.

I'm in the final leg of my master bathroom remodel, and one of the things I wanted to address was it's being among the coldest rooms in the house during winter. Luckily I found a local spray foam company who is OK with small jobs, and assured my job might only cost a few hundred bucks. He can use either Open Cell or Closed Cell, flash and batt, or fill cavity. 

My bathroom has two outside 2x6 walls - the exterior wall (along which my new shower will run) and a garage wall (where all the plumbing and most of the electrical is.) Currently there is R19 6-1/2" Fiberglass batts in the walls.  

I'm planning on spray-foaming the exterior wall, as there is no plumbing or electrical in that wall, and I don't think there ever will be. 

I'm going back and forth on tearing off all the drywall on the garage wall, because after some plumbing changes for my new vanity, wiring changes for lights, and ripping off the old glue-on mirror, nearly the entire wall is going to need repair/replaced anyway. 

My worry however, is that while the spray foam will likely make that new master bathroom nice and cozy during the winter, it will also make any future changes to wiring or plumbing a major PITA. 

Should I:

A) try to save as much of the existing drywall as possible, not touching anything on the garage wall in terms of insulation. 

B) use an alternative method of insulation that allows more flexibility while providing some improvements in R-Value - like "Flash and Batt" 

C) run conduit in the walls or create channels in the foam in order to easily route wires or plumbing?

D) fill the stud bays that will likely not be used for anything, and flash and batt those that might?

Thanks for any suggestions!

Just foam it all. What wires will you possibly need later? Install them now.
 

..regardless, foam is easily carved if you ever DO need to run wiring. 

I spray foamed my basement, a few tips.

• In Wisconsin you can buy the kits from Menards.  Good stuff, Dow Froth Pak.  It was about $1/board foot when I got the kits.
• You don't need to fill the cavity with closed cell foam on interior walls/basement walls.  2" is plenty deep. 
  • Because of reason above, I didnt worry if I had to pull wires, but I had all my wiring done beforehand.
• 1200 sqft took me about 3 hours to do start to finish.
• I used closed cell because I was in a basement and also wanted the vapor barrier.  In a bathroom, I would lean hard toward closed cell due to moisture/mold considerations.
• It made a big big difference.  I also did the sills of the house all the way around at 4" give or take.  
• I wore a Tyvek suit, gauntlet rubber gloves, gasketted safety glasses, and had a nice forced air respirator with P100V cartriges for organic vapors.  Spray foam is nasty stuff.
  • The Tyvek suits from Menards were hot garbage.  The ones from Amazon were worlds better.
  • It actually didnt stink as bad as I thought it was, forced air respirator was probably overkill, but it was a $2000 respirator I got for free from work so I couldn't really complain
• I would highly recommend DIY.  It was super fun and rewarding.
• If you DIY, the tanks are the pressure vessels, they will gradually lose pressure as they empty out.  To keep tank pressure high, put the tanks in a cardboard box and fill the box with new spray foam.  This gives you two advantages
  • Gives you a place to shoot extra foam when you need to change nozzles
  • The reaction kicking in the boxes will raise the tank pressure.

Best of luck!

It's totally overkill, but easy enough to rough-in some wiring and boxes before foaming.

Run some PVC conduit with a couple boxes and stab in some 12-2 with a loop in each box leaving a pigtail somewhere you can get to it later.  When you need the outlet later, find the box behind the drywall and cut it out.  Add a box extension (if needed) and enjoy.

 If you ever want plumbing, probably just best to carve the foam.

OHSCrifle said:

Just foam it all. What wires will you possibly need later? Install them now.
 

..regardless, foam is easily carved if you ever DO need to run wiring. 

This.

So I've got a map of how I might be able to keep all my options open for my vanity/mirror lighting situation. 

However, when I talked with my electrician she suggested that I avoid conduit, and I avoid "dead wires" - as they confuse people later on. 

She more or less just wanted me to commit to something. 

I have a hard time with that. 

I like the idea of running conduit. I've seen suggestions on other similar topics about using ENT "Smurf Tube" for this purpose. My only question is how to keep it in plate at the top plate, and does ENT connect properly to normal wall boxes?

In reply to pheller :

Is it an option to just go ahead and put in a few extra outlets now?

You really need to commit to a wiring/plumbing plan before you re-install the sheetrock anyway.  Commit to a plan, foam it, sheetrock it, move forward.   

Figured out the plumbing. I was originally worried my water heater would need a vent to daylight, but it sounds like the plumbing code has changed to allow more flexibility in that regard. Basically I just need the PRV to shoot down into the pan, then from the pan out into the garage. 

The wiring I determined I'm just going to do a few runs down the wall. 

This planning isn't for outlets. It's for vanity lighting boxes. I determined there are at least 3 lighting options for my vanity. 3 Sconces at 60" (both sides and centeR), 2x downlights above the mirror, one downlight above a single mirror (if I use a single sink rather than double). Oh, and potentially hard wired LED mirrors. 

So I'm going to run 5 separate runs to allow those options. 

The electrician might not like it, but apparently the code doesn't say anything about leaving dead Romex in the wall, and merely capping both ends. I could throw on a label to clue in future homeowners of what the deal is. 

You could just put in a single recessed outlet (Google "electrical clock box") and install your vanity mirror slightly off the wall with the wiring run behind it and plugged in. Options forever. 

I would just foam it all but if you want piece of mind put a conduit or two in and pill strings in the conduit secured tight on both ends. I see this quit often in commercial spaces where adding wiring fro all kinds of things down the road is a real thing. When they pull a wire with the string they will also pull a new string with it.