PEX piping caulking question

[DIYorDIE]

Never thought I'd see it, but I searched on "PEX" and didn't find even one mention of it in the over 4.7 million posts here in the Garage Journal.

I know this isn't a forum that deals with too many plumbing-related questions but I thought that surely someone might have run water to their shop/barn/detached garage using PEX and that there might have been some discussion about it but I guess not.

However, I'm sure there are GJ people who have used PEX so here's my question: What have you used to caulk the access holes where PEX goes through an exterior wall?

I have searched on the internet and see conflicting information; it doesn't help when the PEX pipe manufacturers don't come out and definitively state what is approved for use that will be in contact with their product. (Lots of "Don'ts" but nothing definitively affirmative...)

My situation: I recently replaced the failing 60-year old galvanized water pipes in my house with PEX. Because of the house layout, I had to run some PEX up from the underground supply feed, 8 ft up along the outside brick wall of the house, and into the attic soffit to tie into rest of the interior house plumbing in the attic.

I know PEX is not meant to be used for exterior use and cannot be left unprotected to exposure to UV, so I sleeved the PEX running up the side of my home's exterior wall in thick-wall 2" PVC pipe and then covered that with a piece of colored aluminum rain gutter fashioned to create essentially a box-channel vertical conduit. So I'm not worried about any UV exposure (nor any freezing conditions since we rarely get any freezing temps where I'm at).

The PEX main cold water supply line enters the one story house through the soffit, and two hot and cold smaller PEX lines feed the kitchen through small holes cut into the exterior brick wall. Given the layout of the house, that really was the best way to route the PEX lines without having to tear into a lot of interior walls.

I want to caulk the holes where the PEX comes into the house to keep out ants and other small bugs as well as air but it's not clear what is the best or only type of material to use. Definitely not any petroleum-based caulks because of the negative effects on the PEX material but it's not as clear about silicone, bathtub and tile caulk, expanding polyurethane foam, etc. Lots of conflicting information and opinion out there. Wondering if any Garage Journal readers have any expertise or firsthand experience. Thanks.

 

[Colin Len]

I can't answer your question... but in regard to searching... I'm pretty sure it's an issue with the search function. I've seen plenty of talk about PEX on here. I don't know for sure but it may be that the word is too short. I've seen this on other forums where words which are too short or too common and don't hold much significance (e.g. "the" "it") are simply ignored by the search function and display zero results. Probably nice in most cases since it'll keep search results shorter and to the point, but in the case of something like PEX it makes it literally impossible to search for any info.

 

[CNGsaves]

Crazy idea . . . how about wrap the pex plastic portion that goes through wall in thick aluminum foil that is taped down. Then just use normal "caulk" for the penetration hole extra space . . . like plumbers putty around exterior portion just like HVAC guys use for the copper pipes from outside unit. Once outside is sealed up, then while inside use expanding foam to fill up any other space around the pex as it goes through the wall.

 

[Kaizen]

I've caulked the pex interior going from basement and didn't have any issues. pex will expand a little but normal latex caulk will squish and return no problem.
depending on your hole size you can caulk it or if its bigger pack it with foam insulation then caulk. not the expanding stuff but the tubes of it you can pack a crack with. the expanding is fine too but breaks down in sun so I'd want to caulk the gap

 

[jkwilson]

Try going to Google and searching: site:garagejournal.com pex

Most forum search software will ignore 3 letter words because the load on the server from searches is pretty large.

 

[DIYorDIE]

Try going to Google and searching: site:garagejournal.com pex

Good tip - thanks! That worked, although it brings up the discussion in a more 1990's layout look.


But here are two oddities:

1. I had also initially tried to search on "PEX plumbing" here on Garage Journal and still didn't get any hits. A lot of "plumbing" threads but nothing including "PEX" jumped out. Maybe no one used the phrase "PEX plumbing" in their posts.
   
2. After my original post here, I was out on Google just seeing if I could find any information on any other websites. Within 20 or so minutes of my original post on GarageJournal.com, my post was already showing up on Google's search page near the top of the list when searching on "PEX caulking"! That was pretty crazy how fast Google found it after just being posted, but the REALLY weird thing was that the Google search listing said the post was from "10 hours ago" when I had posted it only about 20 minutes ago. That one I couldn't figure out....maybe Google's time clock has a minimum setting of "10 hours"?

 

[jkwilson]

Using the forum search to look for "PEX Plumbing" will return the exact same results as just searching for "plumbing". You might stumble on a PEX hit, but the software ignores all three letter words when forming a search query. Search for something like "red" or "bit" and you'll see it doesn't do the search even though you know the word is on here plenty.

Good tip - thanks! That worked, although it brings up the discussion in a more 1990's layout look.


But here are two oddities:

1. I had also initially tried to search on "PEX plumbing" here on Garage Journal and still didn't get any hits. A lot of "plumbing" threads but nothing including "PEX" jumped out. Maybe no one used the phrase "PEX plumbing" in their posts.
   
2. After my original post here, I was out on Google just seeing if I could find any information on any other websites. Within 20 or so minutes of my original post on GarageJournal.com, my post was already showing up on Google's search page near the top of the list when searching on "PEX caulking"! That was pretty crazy how fast Google found it after just being posted, but the REALLY weird thing was that the Google search listing said the post was from "10 hours ago" when I had posted it only about 20 minutes ago. That one I couldn't figure out....maybe Google's time clock has a minimum setting of "10 hours"?

 

[csp]

Make your three letter words four letters by adding the wild card character * at the end.

Search on PEX* instead.

Your basic latex caulk isn't going to do a thing to the PEX as far as reactions go between the two.

 

[thewatusi]

Duct seal

 

[67carl]

Minimum expansion foam. I just did this today... Maybe it was a bad idea (what the hell do I know), but it seems to work fine. When I searched the net I see the question of Great Stuff w/pex has come up a lot. The only negative I've found is it isn't fire rated (the standard white stuff). I Believe they make an orange one for that.

 

[DIYorDIE]

I ended up also calling the Customer/Technical Support line today for Cash Acme, the manufacturer of the "SharkBite" brand of PEX piping, fittings, etc. I asked them for an approved caulking/sealant for my application.

The girl I talked to says that "foam-based polyurethane" (expanding foam like the "Great Stuff" stuff) is okay to use. She put me on hold to double-check with some other people there and came back on the line and said they agreed, too. One tip she did point out - when using the expanding foam products, apply it in layers because that stuff generates heat as it cures. If you put it on too thick in one pass, the amount of heat it generates could be bad for the PEX pipe. Applying it in layers and letting it cure in-between keeps the amount of heat on the PEX pipe down to acceptable levels.

I also called the Customer Service line at "pexsupply.com" which has now become "supplyhouse.com" and asked the same question about a caulk or sealant product that they would recommend. The girl who answered the call said that a 100% silicone product would work.

(67carl - in your photo, what is that white disk with a largish hexagonal nut type thing in the middle?)

 

[pstnbly]

Duct seal

Duct seal (monkey sh!t) contains solvents and oils and should not be used to seal PEX penetrations. Silicon caulk is used in some transfer plate applications so it should be ok in contact with PEX. Spray foam is ok too. No solvent or oil bearing products should come in contact with PEX.

 

[sixty4]

We always use fire caulk. But that's code around here. Also the pex we use is Viega's Fosta pex so has an insulation on it that helps with expansion and contraction.

 

[DIYorDIE]

We always use fire caulk. But that's code around here. Also the pex we use is Viega's Fosta pex so has an insulation on it that helps with expansion and contraction.

I had seen some discussions about fire caulk on the internet but since my two sets of holes are the penetration points in the exterior brick wall under a kitchen window and a ventilated masonite(?) soffit panel, I didn't think it was necessary. It's not as if I'm running the PEX through interior walls of adjoining living spaces.

 

[67carl]

...(67carl - in your photo, what is that white disk with a largish hexagonal nut type thing in the middle?)

The white disk is an Oatey shower drain flange. The hex shaped thing is a threaded pipe/fitting that goes inside the flange assembly. You use it to adjust the height and is part of a slot drain (see pic), which fits down inside the fitting. I'll be "pouring" my shower pan up to the height of the slot drain edge, sloping upward as it moves away from the drain.

 

[DIYorDIE]

The white disk is an Oatey shower drain flange. The hex shaped thing is a threaded pipe/fitting that goes inside the flange assembly.

Got it. Thanks for the explanation. A picture is, as they say, worth a thousand words.

I had recently replaced the wax ring on a toilet for the first time so I figured it was a drain of some type but way too small for a toilet drain flange. I guess I should have deduced it was a shower stall drain, given that you had the hot and cold PEX lines right behind it, but I just wasn't that quick on the uptake then...

Follow-up question though - since you're saying you're going to be pouring a "shower pan," then is it safe to assume that the electrical outlet in the photo is from the previous use of that area that you're now converting to a shower stall, and the outlet will be removed for safety reasons (or disconnected and just walled and tiled over)?


(Nice-looking drain design, BTW)

 

[67carl]

... Follow-up question though - since you're saying you're going to be pouring a "shower pan," then is it safe to assume that the electrical outlet in the photo is from the previous use of that area that you're now converting to a shower stall, and the outlet will be removed for safety reasons (or disconnected and just walled and tiled over)?
(Nice-looking drain design, BTW)

You are correct sir! Outlet is old work and will be removed (wires already cut and removed). All the plumbing got rearranged as the shower used to be a little phone booth in the middle of the bathroom while the toilet was next to it, taking up a large amount of space for no reason. They swapped positions and now the toity is in a 30" wide space while the shower went from a +/- 3x3ft space to a 4x6ft space...

Old bathroom:

 

[67carl]

New BR in progress. Notice window has been raised as that whole back wall is the length of the new shower stall. Overhead rain shower, wall mounted shower head and a hand held shower wand are planned.

 

[DIYorDIE]

Are you using the crimp rings or cinch clamps for the PEX fittings (or going with SharkBite connectors)? I ended up going with the clamps, which are not as finished-looking where visible, like under the kitchen sink, but I found the ratcheting clamp tool much easier to use in all sorts of tight spaces and odd orientations. Being a one-handed tool also made it easier to hold a fitting or PEX tubing in place with my free hand while putting the initial squeeze on with the ratcheting tool in my other hand.

FYI, here's a thought since you're moving the toilet and have the walls open already. My in-laws were given one of those fancy-schmancy toilet seats with the little washing wand that washes (and air dries!) your bottom after you do your business. It has settings for "Him" and "Her" - to adjust the spray position because it can also wash "her front."

It has an integrated water tank warmer so you don't get a shot of cold water, so with that, the fan, and the spray pump itself, you know it needs a 110v power source. Well, my in-laws' toilet room had no ready outlet or available power feed nearby, so since I didn't know if they were going to use this new toilet seat permanently, we just agreed to string a color-compatible grounded short extension cord from the bathroom GFCI outlet. It's not "Architectural Digest" beautiful but it works for now.

My point is that maybe some time down the road your wife might want some such thing so since you have the wall open now, it would be only a couple bucks' worth of materials to put an outlet near the toilet, run the wiring from it, but maybe not actually connect it to live wiring yet. You could do that later if you intend to power that outlet. For the time being, you could just cover that dead outlet with a blank plate to avoid anyone trying to plug anything into it.

The beauty is that it would be ready to hook up when you need it, and unobtrusive if you never needed it. Until now, there was never a reason to provide an outlet near a toilet (although I understand these "washing" toilet seats are quite common in Japan, and making inroads here for hygenic reasons, along with claims that it pays for itself through greatly reduced use of toilet paper).