Improper plumbing & trying to remodel bathroom/laundry

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That small exposed portion of the ceiling is NOT shiplap; it is tongue and groove boarding often used as porch decking. You may like that look and only you can decide if the work involved is worth tearing down the panels, etc.

Dave Mason
Thanks, madbloodhound. The ceiling pieces are already falling and I can see there are gaps in the tiles where the wall that is going to be removed touches the top. So, I will need to take it down anyway.
I'm thinking I can do a simpler wood pattern on the ceiling like this:d7656ee3e1d69827d199b50e15a74cc8.jpg
but with the boards so it will look more like this (but with everything painted white)textured-ceiling-fix.jpg
I feel somewhat comfortable with my ideas for the DWV system. I'm planning to temporarily use 2 AAVs to avoid having to cut through the exterior wall. Although, one will actually be in the kitchen under the sink because that S-trap is just aggravating. The other AAV will be for the lav and toilet. Toilet vent will come up and merge with lav vent & have an AAV (which will be hidden but still have airflow and be accessible). I'm still quibbling with myself on the exact placement of the pipe with the AAV.

For the washing machine, I'm going to run the trap arm behind the washer and then have a vent go up just after it gets out from behind the dryer, it will go up to about 6" above the top of the standpipe and then run horizontal to tie in to the main vent stack. Although, technically, if it is less than 8', I might be able to get away with just running the trap arm to the main vent stack. Due to the positioning of the main vent, I will probably have to run the trap arm for the tub/shower west a bit and then have the vent come up and have an elbow to run back to meet with the main vent.

I have a diagram of the parts I think I will need (any suggestions of modifications are welcome). I based it on what parts I could actually find for sale & I may change my mind again. I want to have the most efficient use of parts. I should have specified that all of the cleanouts will be 3". (Do I need any cleanouts in different spots?)

When I did my water supply diagram, I forgot about the old washing machine water lines. Instead of moving the shower lines, I might be able to eliminate the shower lines & just divert the washing machine lines over since it might be a shorter distance.
Since some of the lines will be moved closer to the edge of the house, they will be more vulnerable to cold. I will wrap them in insulation and I'm thinking of getting those cheap foil insulation blankets that they sell in the camping section and putting some up near the skirting and covering the skirtless part to keep warmer air in and colder air out. For the skirtless part, it can be moved aside if we need to climb under to access it.

I don't want a repeat of the pipes bursting again. Also, because PVC is no longer allowed above ground and all of my cold water supply lines are currently PVC, I am thinking of transitioning to PEX. I have 3/4" PVC & CPVC so I'm thinking of going with 3/4" PEX. I'm currently looking in to the options and trying to decide between PEX-A and PEX-B. I'm also trying to decide on fittings. The crimping tools look expensive and I don't know if I have the hand strength to use them (unless they've made them easier to use than shown in some of the youtube videos). I'm also concerned that if I try to use expansion fittings that my lack of coordination may lead to just ruining the ends of the PEX by overstretching or not being able to get it to go over, but I haven't ruled it out. Even though it will reduce the inside diameter a bit at some parts that merge, I'm thinking of using the sharkbite fittings.

1. Which is more secure? Sharkbite (push-fit) or Expansion?
2. Do I need check valves on my water supply lines for the washing machine?
3. Can I have a check valve on the toilet water supply line?
4. Where would check valves be installed and do they need to be accessible?
5. Can I run PEX from the shower valve to the tub spout? (I plan to get an IPS valve rather than a CC one)
6. For the IPS valve, what sort of bonding material do I need to use on threaded connections? (pipe dope?)
7. How hard is it to convert from a 2 handle shower system to one handle pressure balancing/temp control system?
8. Can I use the existing metal piping from the old shower and use some sort of couplings to link the metal to PEX to go from the showerhead to the moentrol valve?
Since I can't edit my posts for some reason, I just had another thought. I was thinking of tying the toilet drain in with the lavatory drain but that would mean it would be inside a load-bearing wall. Neal mentioned that there might be something in the bottom of the wall that would make it so I couldn't drill through. So, revised idea:
*Kitchen drain runs north to south toward the main soil pipe. Vent for it would be an AAV.
*Washing machine standpipe would run behind the dryer and then up above the shelf where a cleanout could be hidden inside a cabinet. The vent would then take a turn to run toward the main vent line and tie in there.
*Tub drain would vent inside the wall, tying in to the main vent.
*Toilet drain would run south to north, venting up in to that non load-bearing wall and tying in to the main soil pipe. A combo wye with cleanout would be under the closet flange.
*Lavatory would have an AAV (at least temporarily) and be under the cabinet rather than inside the wall in a special box with a grill cover. The drain line would have a cleanout at the south end and the line would run south to north to meet up with the main soil pipe. I could use 2" pipe instead of 3" for that line then and use a reducing combo wye to tie it in.

I will try to get some diagrams up later. But how does that sound? (I know AAVs don't sound great, but better than no vents at all). The lazy part of me is seriously thinking of tying the lav in to the existing line directly underneath it where it is roughed in and letting it run to what is presumably a french drain or something.

I think I've changed my mind about the medicine cabinet above the sink-- since it would stick out and block the vanity light somewhat. We already have an existing medicine cabinet that can be re-used so I'm trying to figure out where to put it. Options are, either in the load-bearing wall on the side of the vanity, but positioned so it won't hit the other mirror when it opens, or across from the toilet. If it is across from the toilet and above a trash bin, my brother could shave there instead of over the sink so hair wouldn't be going down the sink.

Any thoughts?
Revised DWV sketch.
The main soil pipe is at least 12" from the vent because it started directly under the original toilet and ran east to west to the septic tank. The original main vent that goes out through the roof is inside the shared wall.

Since I want to have a 2" trap on the tub, I will use the 1.5" tee that comes with an overflow/drain kit to use elsewhere and replace it with a reducing tee that has the top and side outlet at 1.5" and the bottom at 2". The cleanout for the standpipe vent will actually be on the front instead of the side as drawn.DWVlaundrybathrevised.png
What fitting is used for when a vent goes up before the drain goes down? Can I use a sanitary tee on it's back with the sweep going upward in the direction of the vent?
I decided that it might save some pipe if I merge the lav drain with the toilet drain, but I realized I can't do that until after the toilet vents. Since the toilet is on the exterior wall, I could run the vent under the house behind it (I have 3 options for that) and the lav could tie in to the toilet line nearby.DWVlaundrybathrevised2.png
I'm trying to decide on the best option for my toilet setup though. Which option do you think is the best?Toiletplumbingideas.png
Thanks! That's the current plan. I'm just trying to figure out the best fitting combo to make it happen. If the vent pipes I have on the other side of my house (that I will be removing) are the right size, I can just use them. Hell, even if they are 3" I can still use them and just use 3" fittings instead of reducing fittings. They already have the support straps, screws, and are the right size to get around the soffit. If the vent ends up having to be taller to reach the soffit, I can always add an extension piece.
Someone pointed out to me that options B and C would be running a vent horizontally below the flood level. So, it looks like I'll have to go with option A.
First, I don't see a horizontal vent in either plan. Second, if a flood were to get as high as your vents the house would be a total anyways.
First, I don't see a horizontal vent in either plan. Second, if a flood were to get as high as your vents the house would be a total anyways.
"Flood level" doesn't mean an actual outdoor flood. It means the highest level at which a fixture fills before it overflows.
In B the vent starts at the side outlet of the wye. It is running horizontal before it has the upward bend. Same with C only it has a tee instead of a wye. Those two setups would allow water to flow in to the vent and block the air.
OK, that makes sense but in going back to your diagrams I presume all your vents are drawn in "gray" color and I don't see any horizontal that would be below a fixture overflow. But that's OK as it seems that you know what you're doing.
OK, that makes sense but in going back to your diagrams I presume all your vents are drawn in "gray" color and I don't see any horizontal that would be below a fixture overflow. But that's OK as it seems that you know what you're doing.
Yes. I drew all of the vents in gray.
Ah, I was talking about the little image of the toilet drain options. The diagram of the full plan has option A drawn in.
Option C is how my current original toilet is connected (sanitary tee under the toilet flange). It goes from PVC to a reducing Fernco fitting that doesn't have straps.
I hope I know what I'm doing. LOL. Thank you for the feedback, I really appreciate it.
I used the previous sketch to put together one that has the fittings pasted in. Due to limitations in the angles of the photos, sizes, etc, it is not to scale and the angles aren't right.
The oddly positioned vent 90 is horizontal going around a corner in to the wall.

I do have a question about the cleanout on the laundry drain: What sort of tee do I need? Can I use a "test tee"?
I found one here:

I have had trouble finding good angles on photos of the washing machine vents/drains that have cleanouts.

Is that the correct fitting? If not, what do I need?
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Out and around the soffit, I would go straight out the roof or go across the attic to the other vent.
I know it isn't ideal, but I'm not comfortable with poking holes in the roof (which is metal) and it would be more difficult to go through the attic. Plus, I already have the vent pipe and the ties for a useless vent on the west side of the house. I can re-use it. Although, I will probably paint it white to protect it from the sun.

I'm still not sure on the cleanout for the washing machine though.
Frodo answered me on the plumbing forums. He said I need a 2"x2"x1.5" sanitary tee (sweeping downward) with a cleanout welded to the inlet. He recommended heights and confirmed for me that the standpipe P-trap needs to be solvent welded. He also said that the washing machine drain needs to tie in at least 5' away from the other fixtures to avoid suds bubbling up into them. I'm not sure if that is somewhere in plumbing code or just a recommendation.
So, the good news is that my mother is completely on board with the reno now and is willing to pay for it herself (rather than have me pay for it) so the budget can be expanded a little more.

We were thinking of getting a flooring from Samsclub that looked good in person. After calculating the wear layer (they gave it in mm) I saw that it's only 12mil, it has no underlayment, & with tax & shipping it is almost $300 for 7 boxes (which is what I would need to cover the laundry room). I recently saw that HD had a nicer flooring on sale. It would take 5 boxes w/ free shipping & even with tax it would come out cheaper than the Sam's stuff. Additionally, it's waterproof, has a waterproof built-in underlayment, and a 20mil wear layer. Trim pieces are available on the mfr's website.

On HD it's called MSI Herritage Antique Mahogany but on the MSI website it is called Prescott Braly. I'm trying to figure out which (if any) of the trims I would need. I'm thinking the reducer piece might work to go from the vinyl plank to the vinyl sheet in the bathroom doorway. I can just re-use the existing thresholds in the doorway that transitions to carpet. Another reducer might be in order for the transition to the inside of the closet. I'm also not sure what I would need to transition ot the kitchen which currently has the ruined wood parquet. If Mom likes this stuff enough, we might consider using it in the kitchen.
If there is a height difference where the two floors meet, then you want a reducer, which has a high side and a low side. If the floors are even where they meet, then a t-molding is fine. Of course you can reuse the thresholds you already have if they can lay flat enough. The transitions at HD are about 6 ft long, so generally you can get two doorways from a single piece.