Grade My PEX Install

[ngen33r]

As stated, please have a look and give me some pointers on my PEX install.

 

[Terry]

Will you be venting the washer standpipe? Right now it looks capped.

The PEX looks good.

 

[Sponsor]

 

[James Henry]

I would nail a 2 x 4 flat behind the pex and secure the 90 degree braces because of water hammer and don't forget nail plates.

 

[wwhitney]

What are the plumbing code rules on nail plates? I know the NEC is for any wiring within 1-1/4" of the nailing surface of the framing. Of course, they are cheap insurance even if you are farther back.

Also, I think technically the 3" DWV through the 2x6 studs require a stud shoe to reinforce them. The allowable hole diameter for a non-bearing wall is 60%, or 3.3" for a 2x6, while the 3" DWV is 3.5" OD. Not sure how this is usually handled.

Cheers, Wayne

 

[ngen33r]

I made a reply a week or so back and it must not have stuck. The cap for the washer pipe is to keep the gases contained. I am going to put a AAV in the rim joist location in the ceiling until I redo the kitchen and can vent to the roof.

I appreciate the info with the nail plates and securing the bend supports. I planned to do that but have not implemented it yet.

I looked high and low for stud shoes that will fit a 3in pipe and none are available. I read that 1.5in is the minimum needed for a non load bearing wall even on a 2x6, but I am not sure if that is true. I purchased some 16GA strapping that I plan to reinforce the 2x6 with if a shoe is not available. I could also T in a 2x4 flat as a support if that works or worst case make a shelf wall

I do have a question about supporting the 3in pipe. DO I need to use hangars or can I secure the pipe with the fire block foam that needs to be added in the gap? I will be working this weekend on this space again so hopefully I can make some good progress.

As always, I appreciate the help from everyone. Since a lot of us are on lock down, I'll share a virtual beer too.

 

[wwhitney]

In re securing the 3 in pipe, as to the run through the studs, it doesn't need any additional support. [Although if the holes are oversized vertically, you could assume it will sag to the bottom of the holes, and if that would give you a dip, I would support it by shimming or foaming it to keep it in line.]

The fire block foam to my knowledge is only required where a hole would connect a stud cavity with a joist cavity. [There is an argument that if the run is over 10', you should foam enough studs to split it into unfoamed sections of 10' or less.]

I'm also a bit unclear on the code-compliance status of running 3" DWV through a 2x6 stud. A non-bearing wall stud could be a 2x3 drilled with just 5/8" of thickness remaining at each edge (so 1-1/4" total). So if you've got that much remaining wood cross section, I would argue that it doesn't matter that you started with a 2x6. [It certainly doesn't matter from an engineering viewpoint.]

If your holes have gotten closer than 5/8" to one edge, then I'd push the pipe to that side so that you can put flatwise 2x4s within the wall on the other side of the pipe. [e.g. 1/2" + 3-1/2" + 1-1/2" = 5-1/2"].

Cheers, Wayne

 

[ngen33r]

All of my notches are 1.5in of wood before the 3in pipe. All of my 3/4 horizontal PEX runs are 3in minimum setback. I will still probably use nail guards on everything to be OCD. I will probably foam around the 3in pipe to fully secure the run as I left tolerance gaps to have some wiggle room for the pipe pitch. I feel the foam is adequate but if needed I can add some strapping as the modern PCV hangers are thick and will require me to cut into my POLYISO. My house was built 1 course of block too short so I want to get everything into the back wall so I can do a 1/4 PLY coffered ceiling.

Fun note......I had 16 shutoff valves in the space I am renovating and only 4 fixtures on this side of the house. With the PEX I will be down to 2 for this section of the house, not including the ones for the fixtures on the stub outs.

Progress none the less.

 

[wwhitney]

All of my notches are 1.5in of wood before the 3in pipe. All of my 3/4 horizontal PEX runs are 3in minimum setback. I will still probably use nail guards on everything to be OCD.

If you have 2x6 studs that have been notched 4", leaving only 1.5" of wood on just one side, you're down to 2x2s. I suggest those notched 2x6s should get an adjoining flatwise 2x4 to reinforce them (vertical, turned 90 degrees relative to a normal stud). You can also strap the 3" DWV to the back side of the 2x4 using plastic plumber's strap every 32" - 48".

As for nail guards on the pex, with a 3" setback, don't do it. It will just make your drywall lumpy without adding any benefit.

Cheers, Wayne

 

[Jeff H Young]

looks good to me . wouldnt worry water pipes look deep enough from face of stud plate strap 10 in or 12 should be ok the studs are just holding drywall.

 

[Jadnashua]

I like your use of bend supports and minimizing the needed fittings.

 

[MACPLUMB]

The pex install looks good, with one exception the laundry box the cold always go on the right, and the hot on the left ! why didn't you turn the box over and come in under the bottom with the water feed, as while as the drain

 

[Jeff H Young]

I saw crossed water assumed it was reverse image ?