Ok, I am thinking about doing the plumbing for an addition myself and would very much appreciate your help in laying it out. It is a small addition, just 150 sq. ft. spread out over three floors (so, approximately 50 sq. ft. per floor. In the rear of the house (where the addition will be) the basement is entirely above grade. This will be heavy in plumbing as the 2nd level of the addition will have a half bath and the 3rd level a full bath.

My plan right now is to run a 3" stack up one corner of the addition where both baths will tie into. This "stack" (not sure if this is the right term in this application) will tie into the house's main 3" cast iron stack (which currently services 1 full bath). In general, does this work? In order to get this where it needs to be it will require 3 long sweep 90's, is that overly problematic?

Can I run the 3" stack right up and out the roof and use it to vent the various fixtures? I know each fixture needs its own vent, but can I tie it all up together in the attic and have just one protrusion through the roof?

So, can I check dwv sizes?

Toilet - 3" drain, 2" vent
Lavatory - 1.5" drain, 1.5" vent
Tub/shower - 2" drain, 1.5" vent

Am I right on these?

Hi Stubits...

3 long sweep 90s is a bit problematic, but if you install a wye/1/8th combo. fitting with a cleanout in place of one or two of the 90s you should be fine. Otherwise, you will need to install a dandy cleanout after every 3" long sweep... ok?

All DWV sizes are correct as you stated them..

Now, we need to find out if wet venting is allowed in your area (call local inspector if need be). If it is allowed there will be LESS WORK (see picture on left of big picture).

If only individual vents are allowed in your area then there will be a bit more work needed.. see picture on right below.

You will connect vents and run them up to the 3rd floor where you will probably be best to connect the vents into the VENT STACK (now) at about 48" off finish floor and then run the 3" up and out as you noted...

You can also connect the vents in the attic if that is easier...

There is a lot more rules, like pitch for drains and vents, how vents connect together, hanging pipes, drilling joists, where cleanouts belong, how tall to make the vent past the roof line, etc. We can go over that as you fine tune your plan.. OK?

Let me know if you have more questions...

MARK

Mark-

Wow! This is great. Thanks!

We are governed by 2000 International Plumbing Code which I believe allows wet venting, no?

Now, for the 90's, let me try and explain their function and maybe you can help me find an alternative. The 3" stack will run vertically up the left rear corner of the addition. Starting from the roof, it will come down to the ceiling of the basement level where it needs to run horizontally (about 5') to the right rear corner of the addition. At this point it needs to 90 into the existing building where it will run approximately 15' (in a soffit) along the basement ceiling into our utility closet where it will finally 90 back to the left about 2' to tie into the main stack. Complicated, I know. Does it make sense? Effectively this needs to occur because the main stack is on the far side of our air handler, so the pipe cannot just run straight.

Any thoughts?

Hey again...

If there is no other alternative, such as a pipe underground that you think you might be able to get to then you have no choice...

Most important on all these turns is simply going to be to install cleanouts where they can be accessed if needed. If necessary, can also install an access panel for future.

In terms of the IPC I'm pretty sure they allow wet venting, but can't be 100% sure here because even if IPC allows it, it may still not be allowed inyour town/state... need to check with local inspectional services department to be sure.

Keep us posted as you move along...

MARK

Unfortunately the basement is a finished space and going through the floor would be overly disruptive, I think.

So, a "dandy cleanout" is required by code at each 90, right? Before or after? Obviously if it is behind drywall, then I'll need an access panel. The cleanout cannot be drywalled over, I assume.

How would I use the wye/1/8th combo. Fitting you mentioned earlier instead?

Thanks!

Actually, the wye 1/8th combination fitting can almost be used interchangeably with the long sweep 90... as long as you install accessible cleanouts in line.

In fact, the long sweep 90 and the dandy cleanout is probably best in this case as it allows you to snake the drain in both directions of the drain... ;) The end clean out only allows for cleaning in one direction.

See pictures.

MARK

Great.

I could be way off on this, but I seem to remember from another post that wyes are used for horizontal connections and sanitary tees for vertical?

Correct!

Sanitary tees can also be used on the horizontal to pick up vents as long as they are rolled above the center of the drain line... ;)

Ok, great. That's what I thought. I am starting to work this out in my mind and will try and get something down on paper shortly. Will run it by you then. Thanks!


Mark-

Would it be too much to add a washer into this?


Also, here is a very rough layout of the bath room as we'd like it.

Just a couple of things to point out.

1) The black dot in the upper right hand corner is the 3" stack.

2) On both floors, the wall on the right and the wall on the bottom are original 8" thick solid brick walls. On the main level, we will be framing the wall out with 2x4 and covering in drywall. On the 2nd level, we will be leaving the brick exposed.

3) The floor joists will be 2x12 and will run from left to right (the long way). The floor for the 2nd level will actually be sistered 2x12 because we will be installing an antique clawfoot tub.

4) The left wall and the upper wall are both exterior walls. I haven't decided if I will frame them using 2x4 or 2x6.

So, that said, what do you think? Is this a reasonable layout? It seems intuitive to me. How about from a plumbing perspective?

With the joists running from left to right, I think the only drain that will need to run through a joist is the 2" tub drain, right?

What are the rules for notching or boring studs in a load bearing wall? Is it no more than 40%?

I've spoken with a local plumber who confirmed that wet venting is allowed, but I have a call into the inspector's office.

Thanks!

Hi..

If you want to add a washing machine is there any chance you can connect the 3" from the new bathrooms into a 4" pipe instead of the 3" from the existing bathroom? Let me know.

DO not NOTCH studs...drill them. The 1/3 rule applies to joists not studs. With studs you want to keep the hole as small as possible is all you can do.

The layout seems fine... pretty much lays out as I posted at the first picture with WET VENTING... just slightly different.

I'll try to draw up a plan for you in the next day or so... won't take too long.

Answer my question.

Chat soon.

MARK

I do not believe I have a 4" pipe anywhere, at least not above ground, unless I am misreading things. I will post a photo tonight, in case you can see something I am missing. Basically, there is a 3" cast iron that comes up out of the concrete slab and goes straight up to the bathroom. I believe it is 3" top to bottom, but could be wrong.

On the studs, I'll be sure to drill, not notch. My concern is the 2nd floor lav where the 1.5" drain line will have to run through a couple of exterior, load bearing studs. Due to space issues I am thinking of framing out in 2x4, but can I drill a hole for a 1.5" pipe through a 2x4? Also, I will need to drill through the top and bottoms of the studs to bring up the various vents. (I will run the 3" stack in a chase on the corner so I won't have to run it in the wall.

You can drill a 2.25" hole for 1.5" PVC pipe...works fine in a 2"x4" stud (i.e., 1.75" x 3.75").

As you noted, you can bring the stack up in the corner or you could build the wall using 2" x 6" studs....you decide.

I'll wait for the picture...There has to be someplace where there is 4" in the house? Where is the main cleanout? Let me know.

Hmm. Now you have me thinking a bit more about the current setup.

There's actually only 1 cleanout in the whole house that I am aware of. The 3" stack that services the upstairs bathroom passes through a large cleanout about 3' or so before it enters the concrete slab. Perhaps the pipe after the cleanout is 4"?

See if you can post a picture... see what we think here. I have almost never seen a home with only 3"... hmmm?

Let me know.

I will try and get a picture tonight.

For what it's worth, it's an older home, circa 1930 (but you're up in Boston where homes are even older). I know there's only 2 stacks, a 2" and what looks to be a 3", but I could be wrong.

Can I measure it? If so, how?

Yeah... I've been all over new england states and have only seen 3" in a few cottages...so interesting if you only have 3".

Most hubs of cast iron pipe/fittings have a number and an SV (service weight) or an XH (extra heavy) cast into them (raised above surface)... see if you can find the number and which letters are present.

This would be on the hub (the cleanout?) itself? In indeed this is a 3" pipe into a 4" pipe, there should be two numbers on the hub?

I will check on that tonight, for sure.

Also, what do SV and XH stand for?

Reread my last post regarding SV and XH... ok?

The hub is the enlarged bulbous end on a pipe or on a fitting... see picture.

Great, will do!

Sorry... I posted an updated picture while you were writing.

Ok, so I am pretty sure it is 3" all the way through. I can post a picture if you want, but there is a number 3 on both hubs. I didn't see any other text, although the pipe that runs down through the slab is embossed with the words "permanent pipe."

Now, not sure if this matters, but it is unlikely all of this will ever be going at the same time. Also, we have a new high efficiency washer.

Any thoughts?

The newer high efficiency washing machine is actually what I was concerned about.. LOL

Here I would have to refer you to that local inspector you said you would talk to regarding wet venting (although plumber friend said was OK).

I think you are pushing the limits. In my area you can have a great number of fixture units on a 3" drain line, but 3 toilets is maximum (in some areas TWO is maximum)... and now the high efficiency washer plus all the fixtures... hmmmm?

Always best to check with local authority.

I'll draw the plan up tomorrow sometime... based on wet venting... :)

Let me know the details as you get them.

.

Mark-

Thanks so much.

Out of curiosity, why is the high efficiency washer worse? I thought it uses less water?

Let's not worry about the washer. It would have been easier to tie it into this, but there is another option all together. No worries. Let's just stick with the additional 1.5 baths?

Still waiting on a call back from the inspector... they're not particularly helpful/friendly/responsive here. But I feel confident on the wet venting thing, the plumber I spoke to is licensed and does plenty of work here.

The high efficiency washer uses less water but the new pumps pump at a greater volume and pressure than the older pumps did.

Check with that inspector to see MAXIMUM number of toilets on a 3" drain line in your area... we can take it after that... ;)

Thanks...

MARK

Mark-

I finally heard from the inspector right before I left.

He confirmed that wet venting is allowed.

He referred me to the IPC and indicated the following regarding fixture units:

WC=3
Lav=1
Tub=2
Washer=2

So, I have 3 WC(9), 3 Lav(3), 2 Tub(4) and possibly 1 washer(2), so at most I have 18 fixture units.

He added the that I can have the following:

Horizontal Branch= 20 units

Total per Branch Interval=20 Units
Total for Stack of 3 Branch Intervals or less=48 Units
Total for Stack of More than 3 Branch Intervals=72 Units

He also indicated that with a 1/4" slope we can have up to 42 units on the main drain

So, he said, without of course reviewing any specific plans, that I should be fine, even with the washer.

Am I totally missing something here?

Thanks!

Nope... just wanted to be absolutely sure.. ;)

Let me know where you are planning for the washing machine... add it into the drawing and I'll draw up a final print... ;) I won't be on until later tonight.. ;)

MARK

Thanks so much. I am glad everything seems in order.

The washer is more of an add on here and is actually not a part of the addition. There is a closet on the main level of the home (where the powder room will be added) where we would like to place the washer. It is located such that the drain from the washer would tie into the new 3" horizontal run after it enters the existing house from the addition. My thoughts on the vent would be to run it under the 2nd level floor and tie it into the powder room vent. Can this work?

Mark-

Just checking in on this. Not sure I can add the washer to the diagram as it is on the other side of the home. Maybe I can explain it though. It is on the same level as the powder room. The drain would be a straight shot to the horizontal 3" running from the addition to the main drain, somewhere between the 2nd and 3rd long sweep.

Thanks again for everything!

OK... I'll work it in where you mentioned. I'll draw this all up over the next day or so, but will definitely post all by Saturday sometime...

Talk then...

Mark-

Just seeing this now. Thanks, I can't appreciate your help more!

Can't wait to see what you come up with.

Many thanks and best!

Bump?

I got the BUMP... ;) I'll work on this tonight. I should have it posted by early AM.

You're great. Thanks!

Sometimes... just need the extra reminder is all... :)

Thanks.

Hi Stubits:

To begin with... when you lay out the joists for the new addition make sure that the first joist in from the outer wall does NOT end up anywhere near 12-15" to center from the finish wall....if it does you will end up having to cut or head the joist off...so be aware of toilet rough when laying out the joists upstairs and downstairs..ok?

Next, if you install the tub as you drew it with the shower valve on the end opposite the outside wall then you will need to add an 1.5" vent for the tub... it will be too far away to utilize the wet vent from the sink. I drew the 3rd floor bath with the tub being wet vented (in other words I turned the tub toward the outside wall as I figured the pipes would be exposed since this is a clawfoot tub... right?). If you decide to keep it the way you presented it then yoou will need to add the individual vent and connect that back into the vent pipe from the sink or washing machine.

I did not include al the 90s you mentioned... you can place them as needed. I did include the washing machine with a rough idea of how to install it.

Most important with the washing machine is that you pipe it 2" with a 2" ptrap and the standpipe coming out of the trap should be about 30" tall (keep fittings close to floor for this to work out well.

The toilet closet flange roughs in at 12" from the rough stud wall.

The sink drain should be between 18" (for vanity) and 20" (for pedastal) off the finish floor.

The tub drain will need to be determined by where you intend to place your clawfoot tub. The waste line usually transitions over to the tub waste and overflow assembly below the floor but with a desanco fitting about 1/2" above the finish floor. We can discuss this more later.

I have included two drawings. One is a side view diagram. The other is a top down view (waste pipes only)... hopefully, combined these will make sense.

Check out the drawings and let me know if you have any questions...

MARK

Wow, this is great!

Couple of really immediate questions, I am sure mostly because I am not accustomed to reading these diagrams.

First, in general, is the main 3" stack located in upper right hand corner?

Second, on the full bath, is the toilet located on the same wall as the lav?

Never mind! Looking at the second set of drawings, it is totally clear.

OK, so some real questions...

What do you mean when to roll the wye above the center of the drain?

Also, how accessible do the cleanouts have to be?

Finally, I read, somewhere, I don't know where, that if you have multiple 90's, but they are less than 40' apart you only need one cleanout? Yes, no?

On the 1/2 bath, you want to roll the 3"x2" wye above the center of the drain line for the vent to be a legal vent.

On the full bath you want to roll the 3" x2" wye above the centerline for the same reason as above, but the 2" wye for the tub can come off the 2" drain line it shares with the sink just slightly cocked above center.

Cleanouts need to have 18" minimum clearance and need to be accessible. After 2 90s I would install another cleanout. Easy/cheap to install now... sucks later... ;) Just in case the inspector insists on extra ones... you know?

Keep 'em comin'...

Post more questions when they come up... I'm off for now. I'll be back on later tonight!

First, what does 18" of clearance mean? The cleanouts can be installed behind an access panel, right?

What type of fitting is used to connect the vents on the vertical?



Also, curious about implementation.

So, the floor joists will actually run just the way you drew them in your diagram (great job!), they will be 2x12, and in fact in the 3rd floor I will sister them just to ensure they hold the weight of the tub.

First, the plan is to run them 16" on center, as such the first floor joist in should be about 15.25" off from the wall, will that work? If not, how is this usually handled?

Given the size of the joists, I should have no problems running the 2" tub drain, right?

How about running the 2" vent pipes in a 2x6 exterior/load bearing wall? How about a 2x4 exterior/load bearing wall?

18" clearance simply means that there cannot be anything... except an access panel... in front of a 3" cleanout for at least 18"... so a plumber can snake the drain without obstruction.

To install the vents into the vertical stack you will use either a sanitary tee or a double sanitary tee fitting. This fitting needs to be turned UPSIDE DOWN so rain water can run down the stack and whatever water flows into the sanitary tee will drain back to the pipes by gravity...

Note here, that all vents pitch away from the stack toward the drain at about 1/4" pitch per foot (see picture). Drains pitch at 1/4" per foot toward the stack.

Now, the joists... I just wanted to be sure you understand that the first joist must be taken seriously as it could have consequesnces down the road. As long as you actually stick to 16" on center...you should be fine!

No problem on 2"x12" for tub drain. On a 2"x6" joist you would need to keep the drain/trap high up in the joist bay to install the trap properly. With a 2"x12" joist...run pipe as gravity allows. Ptrap depth should NOT be an issue here...;)

A 2" vent requires a 2-9/16" hole which works fine in a 2"x4" exterior load-bearing wall (3.5" wide). It is really no different than installing a 4" pipe in a 2"x6" wall. As odd as it seems.. it is permissible!

Keep throwin' them out as you think them up...

Ok, so far everything is making tremendous sense. The graphics are excellent. Just out of curiosity, what program did you use for the DWV drawings?

Ok, so two more questions...

1) This is a very simple question, but how exactly do you measure the 1/4" pitch. I am sure you must use a level, but are there any hints or tricks? Where on the level is 1/4"?

2) How do I tie into the cast iron stack? I know I need to support the stack, right? Any tricks or tips here? Then, how do I go about cutting the stack, can I use a metal blade on my reciprocating saw? Is there something better? How much do I cut out? What fitting do I use to tie in?

I use my paint program... ;) Then I save as a JPEG file so it will fit the size requirements of the site.

In terms of pitching pipes at 1/4" per foot... if you use a two foot level you can tape a 1/2" block of wood (or metal) on one end of the level and then when you place it on the pipe and it reads level you know you have 1/4" pitch per foot of pipe.

If you use a 1 foot level, tape a 1/4" piece of wood. If you use a 9 inch torpedo level you would tape a 3/16" piece of wood, etc...

In terms of supporting the cast iron stack you will want to purchase a RISER CLAMP (see pictures)... install under a HUB if possible and then use 2"x4" studs under the ears to support the hanger (see other picture).

You can use a reciprocating saw with a bimetal blade (8-10 teeth per inch) or a diamond sawzall blade by Lennox (if you can find it at a local plumbing supply store). You could also rent a snap cutter... but I don't recommend it for this case as it can also crush pipes and cause even more work for you. Stick with the sawzall.

Whn you plan for the cut, measure the fitting and add 3/4" to total length to be cut from the stack... this will help to accommodate the RIBS in between the clamps and allow a little play for a slightly crooked cut.

Finally, use shielded clamps (cast iron x cast iron) and 3" NO-HUB cast iron sanitary tee fittings... do not install PVC into the stack... OK? The NO-HUB cast iron fittings are available at all plumbing supply stores. Then transition to plastic using a 3" cast iron to 3" plastic shielded clamp... ;)

Let me know if need more...

MARK

Ok, I don't think it will be possible to install the riser clamp under a hub, there isn't a hub anywhere accessibly above where I will have to tie in. Is that horrible?

Does the riser clamp and the 2x4 supports remain in place permanently? Or just until after the connection is finished?

OK if no hub to go under... just tighten the clamp real good!

You remove the clamp and studs after you finish installing the clamps... ;) That is why you install cast into cast... axial loading is best with cast on cast!

This seems really manageable.

So, a related, but off topic question. Here in DC, only licensed plumbers can pull plumbing permits. I have a number of friends who have hired a plumber to simply pull the permit, spot check the work and be present at the inspection. I'd really like to go this route, I am sure I can get hooked up with a plumber. Have you ever done this (I doubt it)? Any guesses at a fair price?

No guesses at a fair price... simply wouldn't be helpful as prices for material and labor vary greatly from town to town, etc...

I have actually pulled a permit for someone else doing the work. We meet and discuss the work, they do the work, then I inspect the work, set the temperatures as required (120F to house and 112F to the tubs/showers) and then stand for inspection. I have only done it twice.. once for a friend and the other time for a guy that paid me a lot of money! YUP! 'fraid I sold out for money!

How much did it take for you to sell out? Less than if you had done the job, right?

I basically doubled my hourly rate was all... seemed reasonable! Took like 4 hours total time to lay out, discuss, inspect, pull permit and set temps.

Ok, great. That is my thinking. You and the homeowner made out on the deal. He saved a ton on the labor and you made twice your hourly.

Seemed reasonable... :)

OK, so it is not unheard of, right? With all your help I should be in pretty solid shape.

Just out of curiosity, what do you mean by setting temps?

Now, back to our regularly scheduled plumbing support...

When cutting through the cast iron stack, how important is it to have a straight cut? Any tips or tricks on getting a straight line?

Not unheard of, but I expect you will have some trouble finding someone out there... but someone will help!

Code requires that the water heating source have an output of 120F at all hot water outlets except for tub and shower valves.

The tub/shower valves are required to have a temperature limiting device that allows adjustment to the required 112F. You will find it mentioned in the installation instructions of your new valve .

You will need a thermometer in the correct range for this. They can be found at all plumbing supply stores. This is required before calling for final plumbing inspection (at least in my area... fihuring in your area as well!).

In terms of cutting the stack, take a piece of paper and wrap it around the stack, square the paper up so edges meet and then trace the straight line onto the pipe. Follow this line and the cut will be pretty straight!

Back to you...

Excellent. Also, don't think I mentioned this, but excellent idea on the level. Do you really do that, or are you able to eyeball it?

On the vertical runs of the DWV, how often do the pipes need to be supported? What do you use to support them?

Months ago you helped me plan out a house repipe with PEX. I opted to hold off on doing it until this addition goes in. Figure if I am going to make a mess of the house, I'm better off doing it all at once. So, a couple of questions to make sure I've got it right...

1) I will be using a manifold system. Should I run 3/8 or 1/2 to each fixture?

2) Depending on the above, what size hole should I drill, I know PEX expands?


Also from a previous conversation...

We will be putting a laundry closet on the second floor of the house, while we hope it never leaks, we want to be prepared. I've seen you recommend an automatic shut off system and/or a floor drain. In my application, what do you suggest?

Thanks!

I have a pitch level for bigger jobs and other than that.. I eye ball it on the site glass of the level... you can play with that before beginning... ;)

On vertical runs of DWV pipe you want to support at every floor and wherever it seems to make sense to stabalize the pipes. Galvanized clips under a fitting work well here. Horizontal runs are supported every 4 feet.

PEX

Run the 1/2" as a minimum to all fixtures. You will reduce to 3/8" compression using shutoffs. If you plan on installing high volume shower valve or multi. Head shower system then you will need to run 3/4" pex as a minimum to the showers... you would run these separate of the manifold. Hole size just needs to be 1/4" to 1/2" wider than the pipe.

Washing machine:

I like the floodstops (see pic.) with a pan for all second floor washing machines. They aren't perfect but they are better than nothing. Most important will be to buy the regular single lever shutoff (symmons or watts) and actually use the lever to shut off the water supply after each use. SS braided hoses are also a must!

The floor drain is a great idea, too, but the trap for the floor drain would also require a TRAP PRIMER to be installed and the floor would need to be pitched to the drain for the floor drain to be really useful during a smaller flood or washer overflow.

You could also combine both the floodstops and the floor drain.. up to you.

Excellent.

Back to PEX for a moment, if you don't mind...

1) Do you have a preferred manufacturer? Which product do you trust the most?

2) How do you handle the stub outs for the various fixtures, lavatory, toilet? Is there a method that will allow me to avoid copper all together? How about the stubouts for the clawfoot tub? Of course these will come up out of the floor?

3) How do you handle 90 degree turns?

I use the viega system... in my opinion, the best pex system. When running water or heat I use the FOSTAPEX... it is form stable and looks clenaer or less like spaghetti then the non-fosta piping.

Viega PureFlow - MANABLOC water distribution system, ViegaPEX tubing (http://www.viega.net/4693.htm)

This may not be readily available in your area. If it is, you may be able to RENT the crimping tools from the distributor instead of purchasing them.. ;)

Now, I am someone that transitions over to copper pipe before I stub out (see picture)... this way I can use all the regular finish shutoffs that I have always used. You don't have to as most manufacturers have shutoffs that fit their system... so you may not have to transition to copper.

When I do transition over to copper I make up a bunch of copper pieces with caps and elbows and solder them all together with a pex adapter. I count up all my hot and cold stub outs (I don't count tubs/showers as can direct connect PEX to these valves) and make up that many.

Then I go around and secure these stubs to where they belong using clips/hangers, etc. and then I run the PEX and crimp onto the stub outs. This is a fast way to do the job. You could also purchase the ready made stubouts from viega, but they cost a lot... much cheaper to just make them yourself.

Excellent. That Fostapex is like 3 times the cost of standard Viega Pex, is it worth it? None of my work will be exposed at all.

Do you use the Press or the Crimp fittings? Does it matter?

To avoid soldering, can I use something like this?

HydroPEX H180500 - $4.11 - HydroPEX - 1/2" PEX x 1/2" Copper (3-1/2" x 8") Copper Stub Ell (http://www.pexsupply.com/HydroPEX-H180500-1-2-PEX-x-1-2-Copper-3-1-2-x-8-Copper-Stub-Ell-3768000-p)

Fostapex is a little under double the cost of regular pex in my area, but if no exposed piping regular PEX is fine!

I mentioned, "You could also purchase the ready made stubouts from viega, but they cost a lot more". They would definitely reduce the number of soldered joints behind the wall and if you're not super confident in soldering then this is definitely best approach!

You can use compression shutoffs (see pic.) to reduce the number of soldered joints outside the wall, too.

Symmons and Moen (I think) make a viega PEX tub/shower and shower valve that would allow direct crimp to the valve... can be ordered at any supply house/internet site that works with viega.

The clawfoot tub... (I missed that in the last post):

You will need to run the pex to a threaded FEMALE adapter that gets secured so it is about 1/2" above the finished floor... this allows you to grab the fitting while tightening in a CHROME threaded nipple say 18" tall that threads into a ball shaped faucet attachment (or whatever faucet you choose). Then you slide a bell flange down the chrome nipple to cover the adapter sticking 1/2" above the floor. The chrome nipple may be a special order... OR note here that you need to decide on the exact faucet you want and then rough it in according to the manufacturer's instructions.


.

Excellent. Thanks.

Do you prefer the PEX Crimp method or the Push Pex? Does it matter or should I go with whichever is easiest to get the tools?

How do you handle right angles/90 degree turns? Do these work? Plastic Bend Supports - Wirsbo Plastic Bend Supports - PEX Plumbing - PEX Plumbing Installation (http://www.pexsupply.com/Categories.asp?cID=523&brandid=)

Thanks for the confirmation on the stubouts. I am sure it is much more expensive, but given the small scope of the project, I don't think it will break the bank and will keep me from burning the house down.

I think I understand the clawfoot tub setup, but how do you manage to get the adapter secured 1/2" above the finished floor?

Also, I think I will hold off on repiping the upstairs bathroom until we go to renovate it in a couple of years. Can I connect PEX to galvanized steel? I'd imagine the answer is yes, but I'd need to use some sort of a dielectric fitting, right?

Finally, just out of curiosity, what do you think of the prices on this website? Are they good, bad, close? Viega PEX Tubing - ViegaPEX Tubing - Vangurad PEX Tubing - PEX Tubing (http://www.pexsupply.com/Categories.asp?cID=827&brandid=)

Definitely prefer the CRIMP method. I have seen some of the push type pex fail... so not a fan there.

I handle 90 degree turns using the exact hanger you posted... ;)

Small scope of the job does make sense to go with prefab stubouts... good call!

I will draw up a great way to hang the adapters for the clawfoot tub.. give me a day or so, but you will like it... promise. BUMP me again if I don't get back quickly.

Dielectric fitting is essential... another good call! A union is great if pipes are exposed... if not, need to find another alternative fitting.

Finally, I will need to check prices tomorrow to compare against your prices... let you know when I post my drawing.

MARK

Also, I think I will hold off on repiping the upstairs bathroom until we go to renovate it in a couple of years. Can I connect PEX to galvanized steel? I'd imagine the answer is yes, but I'd need to use some sort of a dielectric fitting, right?


Dielectric fitting is essential...another good call! A union is great if pipes are exposed...if not, need to find another alternative fitting.

Plastic to galvanized, use a dielectric fitting? Doesn't make sense to me AT ALL unless I'm missing something.

Where is the two dissimilar metals when using plastic and galvanized? Just don't get it.

KISS the adapter between PEX and the galvanized will be made of BRASS (male or female thread) if you are using the VIEGA PEX system.

Brass to galvanized equals dielectric fitting... ;)


MARK

In order to get that electrolysis action, you need to complete the circuit.

Ground to Galvanized - ga;vanized to brass - brass to pex and you need an electrolyte between the brass and the galvanized. Water is kind of a poor conductor unless it is moist on the outside of the fitting.

So, if thereis water on the outside of the fitting, then a dialectric needs to be used.

If it's on a totally dry locaion, then doesn't likely matter.


The dialectric union is necessary, but further investigation, I believe is warranted in this case.

You need two disimilar metals, an electrolyte and a "circuit".

You have A. You may have B and you have a lousy C. Furthermore, the brass mipple will be insulated somewhat with the teflon tape.

For something that is going to be replaced, the extra expense might be avoided.

Thanks to you both. Perhaps it is overkill, but really, there are only two connections that will be affected. I think I'd rather be safe than sorry. And yes, I intend to replace it, but it is hard for me to predict when and I'd rather not have any added pressure.

So, Mark, a couple more questions...

1) So, the 90 degree bend support would be used for example when PEX goes from a horizontal floor run up into a wall, right?

2) With the dielectric fittings, can you explain what you mean by an alternate fitting if the pipes are not exposed?

Thanks!

All circuits have a path. Usually it's metal electrolyte and metal. If metal and matal don't ough, yiu can't have elecrolesysy.\\\\\\\









\\\\\\\\\\\\\\\\\




Metal to meal + some electrolyte has has a botential of creatting a battery. C circuit numbt be created fir this tio occur. Water is the circuit meduim.

Just like a battery:

Has(+) ANode - electrolyte- Cathode, (-) a battery is formed. Once you draw poper, you utilized the battery and corrosion takes places. No water, no junk Iions) no battery.

You vcan have two s=dissimilar metals connevted to gether and put I in a desivator and noyhing will happen,



Have it leak, etc, get dirty and you'll have a have a v=battery,

Pire water is a poor conductor of electricity on the inside/ On the outside, it's not true any more.

Hi all...

Cold water pipes condensate under certain conditions... I say stick with the dielectric fittings. In terms of "alternative fittings" I meant that you could also use dielectric nipples... use a galvanized coupling on galvi. Pipe, install dielectric nipple with teflon tape and then install PEX adapter using teflon tape... just another alternative (and don't need access panel).

The 90 degree hanger is used anywhere you need it, but is most often used when people stub out of the wall for PEX shutoffs and such... ;) Since you are going with copper stub outs... you won't need any there, but you will need from horixontal to vertical for sure.

MARK

Excellent. I understand now. If I use a union, it must be accessible, if I use a nipple, not necessary.

Great!

Yup!

Got you!

See picture...

You would install 1/2" PEX x 1/2" female drop ear elbows to a stud in between joists and then install 1/2" brass nipples and couplings to about 1/4" above the floor. After the floor is installed you can grab the coupling, install 1/2" I.P.S. (iron pipe size) threaded chrome nipples into them and then slide a 1/2" I.P.S. chrome flange down and over the exposed part of the brass coupling to finish.

I think I mentioned 1/2" above floor last time...but go 1/4" as you can use a standard flange to cover the exposed part of the brass coupling.

You want to rough these adapters in so that they are spread apart in relation to the faucet you will be using so choose your faucet BEFORE you rough these in.

Thanks! This is amazing!

Any thoughts on the prices from that website?

Prices are right about what I pay wholesale... so prices are fine there.

Excellent.

Is this to good to be true? NEW Pex Pipe Crimp Pinch Clamp Crimper Tool 3/8" to 1" - eBay (item 260386109257 end time Apr-09-09 19:08:58 PDT) (http://cgi.ebay.com/NEW-Pex-Pipe-Crimp-Pinch-Clamp-Crimper-Tool-3-8-to-1_W0QQitemZ260386109257QQcmdZViewItemQQptZLH_Defau ltDomain_0?hash=item260386109257&_trksid=p3286.c0.m14&_trkparms=72%3A570%7C66%3A2%7C65%3A12%7C39%3A1%7C2 40%3A1307%7C301%3A1%7C293%3A1%7C294%3A50)

That would work for PEX pipe with crimping rings.

If using viegapex... it won't work. You MUST have their crimping tool.

OK, I get it. Does the tool need to be made by Viega? For example, can this work?

PEX Crimp Tool Kit for sizes 3/8", 1/2", 5/8", 3/4" &1" - eBay (item 270325067600 end time May-02-09 08:26:10 PDT) (http://cgi.ebay.com/PEX-Crimp-Tool-Kit-for-sizes-3-8-1-2-5-8-3-4-1_W0QQitemZ270325067600QQcmdZViewItemQQptZLH_Defau ltDomain_0?hash=item270325067600&_trksid=p3286.c0.m14&_trkparms=72%3A570%7C66%3A2%7C65%3A12%7C39%3A1%7C2 40%3A1307%7C301%3A1%7C293%3A1%7C294%3A50)

Nope... that tool is specific to crimp rings like the last one (not crimp sleeves... viega uses sleeves).. ;)

You are looking for something like this:VIEGA PEX PRESS TOOL 1/2" + FOSTAPEX PREP TOOL + CUTTER - eBay (item 270369896097 end time Apr-12-09 15:38:01 PDT) (http://cgi.ebay.com/VIEGA-PEX-PRESS-TOOL-1-2-FOSTAPEX-PREP-TOOL-CUTTER_W0QQitemZ270369896097QQcmdZViewItemQQptZLH_ DefaultDomain_2?hash=item270369896097&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C 240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50)

However, don't pay the price mentioned at that eBay site... HUGE RIPOFF! You can purchase the entire kit (does 1/2" and 3/4" and includes all the gadgets) for about $200.00 either from viega or from a local viega distributor. On occasion viega has a 50% off promotion on the tools... if I see it again soon I'll let you know. Lastly, some local plumbing supply companies rent these to customers as long as they purchase materials through them. It can't hurt to call and talk to the counter guys and see if they are willing to help here..?

Otherwise, I'm sure the crimping ring method of PEX works great, too....maybe best to go with what is available locally. Hmmmmm..?

I see, I think I understand now. I think I'll head over to the local plumbing supply house this weekend and see what's up.

Also, I measured the incoming water main and it has an outer circumference of 3", and a diameter, I believe of 1". So, I should run 1" from the main to the manifold, right?


Mark-

Thanks for everything. Couple of remaining questions...

The incoming water line. It's copper and comes up vertically out of the ground in the basement. I measured the outer circumference and it is just a bit more than 3", which seems to be about 1" in diameter. How can I be sure? I want to make sure I purchase the right tubing, etc. Any suggestions? Also, I can run 1" from the main to the manifold, right?

Also, I have a concern about mounting the toilet. A while back you mentioned how it is important to take the toilet into consideration when framing the floor. So I was thinking it through a bit more and am concerned. The toilet should be set 12" from the framed wall, right? In this case, it will be set 12" from an exterior 2x6 wall. My math has the toilet drain falling dead center on the floor joist. Am I wrong? Any thoughts, suggestions?

Hi again... sorry for the delay. Been super busy and having a run of bad luck with the appliances and the computer at my house this week.

Anyway, let me know if you are using a pre-built manifold or if you are making one yourself..

I will answer the rest tomorrow night... PROMISE! I got to run now.. the verizon guy (cable/phone/computer) just told me my $600.00 TV that worked great until 1/2 hour ago is broken! I swear... just my luck lately!

Let me know...

Uggg. So sorry to hear things aren't going well... getting any better?

I will be buying a manabloc manifold, unless you suggest otherwise.

Thanks!

Hi Stubits...

3/4" copper tubing has a circumference of about 2.75" and 1"tubing has a circumference of about 3.5"... so appears that you do have 1" there.

The manibloc has 1" ports so you could connect both hot and cold in 1" tubing...IF your hot water heater is piped in 1".. Which I doubt... ;)

For a bathroom and a 1/2 I'm confident that you will be OK with 3/4" for both hot and cold water inlets to the manifold... especially since your water heater only has 3/4" inlet/outlet... right?

In terms of the toilet... I see that alot... ;) You may need to rough this in at 10" off the finish wall and purchase a 10" rough in toilet (more money), or finally, you could head off the joist and box out for the 12" toilet rough.

Keep 'em comin'

I will check the water heater tonight and see, but keep in mind the manabloc will be feeding 3.5 baths, 2 laundry rooms, kitchen sink and a bar sink.

I need to see what toilet my wife wants, if we can get a 10", I will likely go that way, if not, I can head off the joist no problem.

Thanks!

I had no idea you were picking up the whole house...

In that case... 1" is best for volume availability.

Eventually the manifold will run the whole house. I probably won't repipe the whole thing quite yet.

In that case, what do I need to do with regards to the hot water heater? Can I repipe it to be 1"?

If you have a 1" port available, you can use it, but you'll have to reduce to 3/4 at the heater. It's a good use for a 1" port.

Eventually the manifold will run the whole house. I probably won't repipe the whole thing quite yet.

In that case, what do I need to do with regards to the hot water heater? Can I repipe it to be 1"?

Mark-

Long time no talk, hope you're doing well. Thanks again for all the help.

Got a couple more questions for you.

1) How can I figure out for sure if my current water main is 1" or 3/4". I am pretty confident it is 1", but would hate to buy materials and run the lines only to be wrong.

2) You were right, my water heater is only 3/4", do they make 1" water heaters, or is there anyway to increase the water heater supply/output to 1"?

3) The design of the bathrooms puts some plumbing on exterior walls. In these instances, am I better off running the water lines up through the floor as opposed to in the wall? That is to say bring the water line for the toilet up out of the floor, same for the vanities, to keep it in conditioned space? We get some freezing weather here in DC.

No 1" tappings on normal size residential water heaters so I would pipe 3/4" into and 3/4" out and run all from there....You won't be running that many fixtures at the same time that I would worry about this. Otherwise, you could run 1" pipes in and out, just not sure it's worth the money... however I see it done once inawhile.

Bring the pipes up through the floor... no question on that. Easy to do and never have to worry.

Circumference of 3/4" copper tubing is about 2-5/8"... 1" copper tubing is about 3.5" circumference... so that should help you determine size.

Keep 'em coming as needed.

Excellent. Running the pipes through the floor won't be an issue at all, really. Thanks so much, I am guessing this saved me a fair amount of grief. Any issues with DWV pipes in exterior walls? Guessing no, but just to make sure.

No issue with PVC pipes in wall. I am sure you already know that no washing machine ptraps should be in any outside walls... just to be clear on issue!

Because of the standing water, right? I think the only PVC in an exterior wall will be a horizontal run for the 2nd story lav.

Correct... because of the standing water... ;)

The lavatory pipe will be fine as long as it is pitched to 1/4" per foot. I end up with lavs. And kitchen drains in outside walls all the time... so you will be fine here!

Hey Mark. Hope you're well. I am hoping you'll see this. I finally have a schematic drawing from my architect. Plans have changed a little bit since we last talked and as such, I'd really appreciate it if you can help me figure out this new setup. The big change is that we're no longer including a full bath in the upper portion of the addition (we'll be adding a full bath on the upper level, but if doesn't factor into this setup).

Does this change much of anything? I figure I will be able to penetrate the roof with a 2" vent, instead of a 3", correct, or should I go up to 3" anyway?

Any thoughts? Concerns? Suggestions?


Mark-

Thanks for all your help. We're finally getting close on this project. We've got really drawings and everything. I'm hoping you can take a peak at this and give me your opinion on how best to plumb the half bath and the washer. As I mentioned, we can wet vent here. I've shown the only real option for the drain pipe to connect to the main stack. I know it isn't optimal, but will it work? How do I go about tying in the washer?

Any concerns? Thoughts?

Thanks!

Hi Stubits!

Here is a quick draw up of how I would pipe this. The toilet gets wet vented by the 2" lavatory waste/vent. The washing machine and the kitchen sink each get their own 2" waste line and 1.5" vents. The kitchen sink requires a 2" cleanout under the sink... so remember that when hooking up the sink. I also like to install a cleanout in the washing machine vent, but it is not required.

All vents connect at convenient spot upstairs and penetrate the roof 2".

Let me know if you have questions...

MARK

This is great. Many, many thanks!

As always, I've got a couple of questions.

First, the kitchen sink is already in place and plumbed, so it's not a component of this project.

Second, I guess we've managed to reduce the number of cleanouts from earlier plans by using more 45's, right? On the topic of clean outs, how far should the cleanout be from where the two pipes intersect?

My goal is to run the 3" pipe through the joists(joists in the house are 2x12 and run side to side, not front to back). Does that seem even remotely possible? Will a 45 work inside a joist bay?

Finally, are all the connections made using sanitary tees, or wyes?

YUP! Cleanouts needed only at the changes of direction as noted in the drawing.

Cleanouts are just cemented into the end of the wye making the change of direction.

3" pipe going through how many joists...?? A 3" pipe is actually 3.5" and will require a hole about 4" in size... if a fitting goes through a joist the holes will need to be even bigger. If you plan on running this pipe down the middle of the house as presented I would check with the local building inspector on this as building codes require that no more than 1/3 of a joist can be taken away from a joist... and you are exactly borderline on that (or passed it if fitting ends in a joist).

Running down the center of the addition like this could also cause concerns... right? I'm pretty sure you can only be so close or so far from the foundation walls... so again, you will definitely need to check with your local building inspector on this. Let me know what he says here.. OK.?

All connections off the main run will be WYE connections as drawn above.

MARK

Mark-

Thanks, this is all great. You're right on the joist issue. It just isn't worth it... I'd need to go through too many joists, too close to the middle of the home, so I'll be doing a soffit.

I've got some questions about how to pull this all together. Just to make sure we're on the same page, I've annotated your diagram, marking 3 question areas.

A - This connection is similar to many in this layout, but I wanted to make sure I understand how it works. Starting from the left (where it ties in to the main stack), you have 3" pvc pipe which gets connected to a wye. One one end of the wye is a cleanout. The other port connects to 3" PVC pipe which connects to a 45 which connects to other pipe. Is this right? Especially the use of the 45?

B- Can you walk me through plumbing the sink? Obviously there is a p-trap which connects to a horizontal pipe (1.5", right?) which connects(how??) to a 2" vertical stack. So, how specifically does the p-trap connect into the "stack"? Also, is it necessary for the "stack" to be located immediately behind the sink, or can it be located 6-12" to the left or right? And, how does this vertical stack tie into the drain under the floor?

C- On the toilet, I think I've got this one, but just to confirm. You've got a closet flange (which should sit on the finished floor, right?) which connects into a closet bend which connects directly to the 3" drain, right?

Oh, and when this all ties into the main stack, it gets connected using a sanitary tee, or no?

Anything I'm not thinking to ask? Any suggestions? Concerns?

Thank

A) YES

B) 2" Long sweep elbow out of the floor into a 2"x1.5" sanitary tee at about 18" to center off finish floor and 2" vent runs vertical and connects to other vents upstairs.
The stack should go 12" left or right to avoid issues with running into water pipes. The 1.5" pipe goes horizontal to pick up the sink and can be centered or go left or right of the sink center 6" either way (if vanity go left or right... if pedestal sink go dead center). Use a regular 90 to come out of the wall and install the PTRAP.

C) The closet flange sits on the finish floor... correct. Closet bend and then connect direct... correct.

D) At the main stack connect via a sanitary tee.. correct. A long sweep elbow should be installed at the base of the stack and a DANDY CLEANOUT should also be installed (read on).

Plan on capping everything with jim caps (2nd image) or wing-nut plug (3rd image) and fill the system with water to the roof vent to test all this. Here, you can install a DANDY CLEAN OUT (also called a test tee) at the base of the 3" stack and install a cherne seal plug (available at plumbing supply store... (4th image). These cherne plugs screw into the dandy cleanout (last image and in cross section in 4th image) and make it real easy to drain the system after filling the system (just release air from the plug and after all drains remove and recap the cleanout). Or, you could wait to connect the stack to the main and use a jim cap with boiler drain (1st image) in it to drain the system and then make the final connection into the main drain.

MARK

This is all really great. Thanks so much!

Regarding the main stack and then the testing. The stack I am tying into is pre-existing, 3" cast iron. Should I still be planning on adding a long sweep elbow? If so, where?

Now, there is a clean out located below the point where I will be tying in. That's good, right? That said, it's an OLD clean out, 76 years old I am sure, and I have no idea when it was last opened. Can I perhaps use this for the purposes of testing? Also, how does this work given that there is a full bath connected to this stack (one floor above the powder room)? Can I still perform the test? Am I confused on something?

Thanks!

If preexisting stack then no need for the 90 degree fitting... correct.

If you install a dandy cleanout after you connect into the sanitary tee fitting of the stack... say a foot or two after you have connected (between sanitary tee and the wye/45 fitting) then you can install the cherneseal test ball into the dandy clean out, fill with air (PSI recommended on the cherneseal), test the drainage to highest point with water and then let the air out of the cherneseal to let water drain (after approved by the inspector) and then just install the cap back into the dandy cleanout and abandon it under the floor.

This will keep you from having any issues with the upstairs bathroom on this stack... ;)

MARK

I guess I am still a little bit confused by all of this. Sorry!

I have a 3" cast iron vertical stack, it comes up out of the basement floor and runs all the way up the house, through the attic and out the roof. There is already a cleanout in the stack, perhaps 2-3' above the basement floor.

My house has three stories, including the basement. The plan is to run the pipes for the half bath and the washer, both of which are on the main floor of the home, through soffits along the basement ceiling. I did not envision having to open up the floor at all. Am I wrong? So, effectively the 3" horizontal run of the new drain will connect to the existing vertical stack, approximately 5-6' above the basement floor. Does this make sense at all?

So, I am wondering, can I use the cherneseal with the old cast iron clean out?

You said, "So, effectively the 3" horizontal run of the new drain will connect to the existing vertical stack, approximately 5-6' above the basement floor."

Install the dandy cleanout and the chernseal AFTER you connect into the stack... four or five feet off the old stack. Do not use the old cleanout. It will cause you to have to fill some of the old pipes.

Install the dandy cleanout and cherneseal about 5 feet off the old stack, in the ceiling where you will be building soffit around it. That make sense now?

This is great. Makes perfect sense now. Sorry it took me so long to catch on.

I have two quick questions:

1) I'll be plumbing the supply lines with PEX. The supply for the toilet will come out of the floor (as opposed to the wall). How do I pull this off?

2) I will need to run the 2" vent through an exterior 2x6 wall. Will I be OK doing so? What size hole do I need to drill to fit a 2" pipe?

Thanks!

1) You can go with a pex shutoff which would only require you to stub up pex and cap it for now... or you could install a pex x copper adapter and stub up copper pipe and cap off until you are ready to install the shutoff at finish (see image... although shown in wall for the lavatory this applies to below the floor for the toilet just as well).

2) A 2" vent in exterior wall is normal practice. A 2" pipe will need a 2-9/16" hole-saw or self feeder bit.

As always, excellent advice. Many, many thanks. I have a similar question, how about 2x4 non load bearing walls. Can a 2x4 accommodate a 2" pipe? Particularly the top and bottom plate? Are the restrictions related to the vertical studs, or do they apply to the top and bottom plates as well. This bathroom is complicated in that it has brick walls on 2 sides, a 2x6 exterior wall on 1 side and a 2x4 partition wall on the 4th side. I am having a difficult time trying to figure out how to run the vent stack. Any thoughts?

Also, as long as the stack maintains 1/4" per ft slope, is it OK if it has some twists and turns?

Yes... it's tight but we do it all the time.

Twists and turns are fine as long as pitched. You have to get the vent out somehow.

I'll think on it, but best path is obviously the shortest path!

Mark- I've got a bit of a thread going on in construction regarding how to channel brick. I don't want to double post, would you be willing to check out what I've got over there? The link is

https://www.askmehelpdesk.com/construction/channeling-brick-plumbing-375076.html

Thanks!

Mark-

It's been a LONG time... I hope you're still out there. I can't believe it, but we haven't yet started this project, but hopefully we'll be ready to go in the next month or two.

Recently I have been reconsidering the decision to run the drain pipe along the ceiling, rather than underground, but frankly, I am intimidated about finding the pipe under the cement slab.

How do you go about doing this? I'd imagine you have a camera or some high tech tool, but is there an effective method for DIY? I am certain the pipe is cast iron, but frankly, I am not sure quite how deep the slab is.

Someone suggested I run hot water in the pipe and use an infrared thermometer. Have you ever hear of this?

Would a Radio Shack grade metal detector do any good?

Any other thoughts?

If you look at the diagram in Post # 93, it shows the main level of the home, there is a finished basement below. Immediately below the kitchen (shown in the diagram) is a bathroom. The toilet is in the lower right hand corner, meaning a 3" pipe must run from the toilet to the main stack, also shown in the diagram. I would like to tie into this, it seems like the cleaner installation method.

Any thoughts?

Thanks as always!

Ok folks, I am not sure if I should start a new thread or continue this here because of the history. Hopefully people still bother to read it!

If you look back on the discussion you'll see we were planning to add plumbing for a full bath, half bath and laundry room. We've reorganized the layout and now we only need to focus on the plumbing for the half bath. We'll be adding a full bath and a laundry room, but elsewhere.

So, I have a couple of questions just to make sure that the walls are being designed to accommodate the plumbing correctly, especially for the vent.

So, my questions are...

1) Am I correct that I will just need a 2" vent? The half bath will have just a lavatory and a toilet.

2) I read somewhere that I need to increase to 3" when I come up through the roof, is this true? Or is 2" fine?

3) Alternatively, is it OK if I tie into an existing vent, as long as it is above the flood rim of the other fixtures?

4) If I go the above route and tie into an existing vent, is there any limits on the length of the vent line? I know it needs to be sloped, 1/4" per foot? More? Less?

5) The biggest question though, is can a vertical 2" vent line be run safely and code compliant through a 2x4 exterior wall? Is it code compliant? And, if it is, are there any risks during cold weather, etc?

6) Instead of all of the above, what about an AAV? An AAV seems like the perfect option here, but do they really work? I'd have no problem making it accessible, I could cover it easily with a mirror? Thoughts?

Thanks for any insights. I have lots of architectural plans if they'd be helpful.

Hey Stubby, Back again I see.

1) Am I correct that I will just need a 2" vent? The half bath will have just a lavatory and a toilet. My code, (SPC) will allow 1 1/2" vents but our inspectors prefer 2" vents.

2) I read somewhere that I need to increase to 3" when I come up through the roof, is this true? Or is 2" fine? 2" exiting the roof will be just fine.

3) Alternatively, is it OK if I tie into an existing vent, as long as it is above the flood rim of the other fixtures? Not just the flood rim of any fixture. There can be nothing discharging above the fixture you're reventing back into, It MUST be a dry vent.

4) If I go the above route and tie into an existing vent, is there any limits on the length of the vent line? I know it needs to be sloped, 1/4" per foot? More? Less? No limit, 1/4" slope.

5) The biggest question though, is can a vertical 2" vent line be run safely and code compliant through a 2x4 exterior wall? Is it code compliant? And, if it is, are there any risks during cold weather, etc?
Are you asking if you can run the vent outside and up a outside wall. Through the over hang and out the roof? Check with your local Building Department.

6) Instead of all of the above, what about an AAV? An AAV seems like the perfect option here, but do they really work? I'd have no problem making it accessible, I could cover it easily with a mirror?
Yes they work but it will have to be OKed by the plumbing inspector before installing.
Good luck, Tom

Thanks Tom.

Regarding running the vent through a 2x4 wall, I meant can I run it in a 2x4 exterior wall, sorry for the confusion.

I have read different things about the AAVs, I know they need to be accessible, but do they need to have a vent/grate over them to allow them to breath? Could I install it behind a mirror?

Thanks Tom.

Regarding running the vent through a 2x4 wall, I meant can I run it in a 2x4 exterior wall, sorry for the confusion.

I have read different things about the AAVs, I know they need to be accessible, but do they need to have a vent/grate over them to allow them to breath?

Yes, you may take the vent up inside a outside wall.

Could I install it behind a mirror? They do not require a grate over them and if you place a mirror the mirror must be removable or on hinges to provide access for servicing. Ya just can't place it inside a wal without access to it. Regards, Tom

Thanks Tom, I've spoken with our inspection office before and they are OK with AAVs, they say given how many older masonry homes we have, there is not much choice.

Do you trust AAVs enough to use them yourself? As long as stay accessible? I imagine if anything goes wrong all I need to do is cut it out and put in a new one, right?

So, if all I have is a toilet and a lavatory, how high up does the AAV need to be?