General advice for possible future addition

[DuaneK]

I'm doing a minor bath remodel on our late 1950's 1000 sqft bungalow. New tile and fixtures, a couple minor supply line moves. BTW I would have never known about TOTO toilets unless I came here, glad I know now.

Anyways my question is about something we might do in the future. Adding an addition that would expand the kitchen/dining area and add a bathroom upstairs. While I have an understanding of the current plumbing, looked in walls, etc. It seems like a good time to ask so I know what would need to be done if we decide to do that addition.

This is a rough sketch of what I know to be current. I know the tub/shower does not have it's own vent. I know the toilet does not have it's own vent. They both join into the main drain/vent just below the floor (at #1). The toilet is directly in front of the stack (so 14"-16" max). The tub/shower is about 32" away. The sink is also about 32" away. I don't know if the sink has it's own vent at #2 (I suspect not). I do know that it does not tie in at #1 below the floor, so there must be a junction inside the wall behind the toilet. I think all this is OK because of the short distance to the drain/vent stack. It is allowed to not have it's own vent. Please correct me if wrong.

Now lets pretend I want to use this main drain/vent stack to tie in a new bathroom on second floor, above the big black line. I'm pretty sure I would need to connect the drain from second floor at #1 or below it. Also the second floor fixtures obviously would need proper vents tied into the roof exit (not shown in my sketch). Something like this (blue is drain for 2nd floor bath):

One issue I might run into is the 1st floor sink to drain horizontal (near #2) would interfere with the drain from 2nd floor (not enough room in wall). A possible solution would be something like this:

The green pipe would need to tie into venting above 2nd floor fixtures. The 1st floor sink would tie into drain from 2nd floor.

Does my general idea or understanding seem OK? We might not do this, and I would hire someone for such a major project. But I'd like to figure out it is possible someday and also know enough to make sure I know it will get done right.

 

[Reach4]

I suggest that you use the search box above for "bathroom group" with the quotes.

 

[Sponsor]

 

[Dana]

General advice on an addition, unrelated to the plumbing aspects- get serious about air tightness- it's the cheapest possible performance upgrade, easy to do for new construction than retrofit:

* an EPDM sill gasket between the foundation and the sill plate.

*Take extra care to air sealing the band joist to the sill plate & subfloor with polyurethane caulk (and don't ignore the IRC's R15 continuous insulation requirement for R15 foundation insulation. (4" of EPS work. A minimalist 2" + 2" EPS insulated concrete form works, as does 4" of EPS glued to the interior side of the foundation, covered with half-inch wallboard.)

*For the framed wall tape the seams of the sheathing for air tightness, and lap tape over the top of the sheathing onto the top plate. Put a bead of polyurethane caulk under the bottom plates & subfloor, caulk the seams of any doubled up framing such as top plates, and the full perimeter of each stud bay.

*Can-foam or caulk all electrical penetrations & framing, including lateral runs from stud bay to stud bay.

*Use air tight electrical boxes, or seal up & can-foam the back sides after installing the wires, and tape the inside of the box to the exterior side of the wallboard under the box plates, for perfect air tightness.

* Any lighting at ceiling level should only be surface mounted LED lights in air-tight electrical boxes. Be sure to air seal any electrical & plumbing/venting penetrations of the ceiling too- bathrooms are damper than most rooms, and air leaks into the attic from bathrooms are more damaging than other random places.

If insulating the walls with batts, use only high-density fiberglass or rock wool, and take care to tuck the edges & corners in for full contact with the sheathing & framing, leaving no convective loops around the batt. Use a batt knife (or bread knife) to sculpt around electrical boxes and wiring for as-perfect a fit as possible- no voids, no compressions.

Install vertical strips of ripped 3/8"- 3/4" OSB or plywood (or 1x4 furring) over the housewrap or felt, leaving a vented air gap between the siding , through screwed to the studs 16" o.c. The "rainscreen" construction forms an excellent drain path and capillary break from wind driven exterior moisture drives, and a drying path for the assembly from interior moisture drives. In Chicago's climate zone (5A) a rainscreened siding setup there is no need for an interior side vapor barrier or vapor retarder tighter than standard latex paint. The drying path to the interior gives the assembly a huge resilience advantage against moisture compared to the typical 4-6 mil polyethylene vapor barrier solutions.

If you're the type who would worry about skipping the vapor barrier even with rainscreened siding, use 2-mil nylon (Certainteed MemBrain) rather than polyethylene. (The Orange & Blue box stores now even carry it in my area, but in your area it's probably cheaper at Menards.) The 2-mil nylon is vapor tight in winter, when the air inside the cavity is dry, but in the summer or if moisture levels in the cavity go high due to an incidental bulk water incursion it becomes more vapor-open than latex paint, so the drying path is there when it needs one.

Code min is 2x6/R20, but if you really want to cozy it up it's not financially insane to add 1.5" of exterior polyiso or 2" of EPS to the exterior of a 2x6/R20-R23 type of wall. It adds a lot of detail, but that much foam keeps the sheathing warm enough to not accumulate significant amounts of wintertime moisture. (I won't go into those details here unless you're really considering it.)

Build in enough depth at the roof or new attic extension to get the full code-min R49 all the way out over the top of the top plate. For mid-density fiberglass or open blown cellulose (preferred) that's at least 14" of insulation depth, and 15" minimum from the top plate to the underside of the roof deck (for the minimum 1" clearance.)

 

[hj]

That is a verbose answer to a question that was never asked.

 

[Terry]

Plumbing for an upstairs bath needs it's own way down and can't use any of the downstairs venting for waste. Ever!

 

[Dana]

That is a verbose answer to a question that was never asked.

Are you sure it was never asked?


General advice for possible future addition

Perhaps reading the title of the thread doesn't count, but I'd call the response qualifies as "general advice for a possible future addition", even if it didn't address the specific questions asked the the original post.

It's so easy to do this stuff right the first time if you plan for it, this is the time to think about it. Many truly shoddy additions get tacked onto fairly decent 1950s bungalows, but it doesn't have to be that way.

 

[DuaneK]

Are you sure it was never asked?


General advice for possible future addition

Perhaps reading the title of the thread doesn't count, but I'd call the response qualifies as "general advice for a possible future addition", even if it didn't address the specific questions asked the the original post.

It's so easy to do this stuff right the first time if you plan for it, this is the time to think about it. Many truly shoddy additions get tacked onto fairly decent 1950s bungalows, but it doesn't have to be that way.

Perhaps you would consider that the thread title was posted to a forum titled "Plumbing Forum, Professional and DIY Advice"
I apologize for assuming that most people would anticipate a plumbing question in the plumbing forum. If your interested in flaming people for being off topic you should really check out the electronics forum here, or the computers and stuff forum here. It's mostly holiday greetings, car talk, sports, fuel credit cards, etc...

If your interested in a real electronics/electrical engineering forum or a mechanical engineering, or a computer programming forum. I can help you find one. I'll warn you that they frown upon being snarky and only reading the title. That said, people like me will try to understand your questions and help you learn. Nobody makes an issue of your "stupid title" if they think you are trying to learn. They don't just say search "Bathroom Group". Or offer verbose advice on insulation and vapor barriers in an electronics forum.

I thought perhaps an expert might read my post and say something like:

Your first sketch is normal for a small 1950's bungalow, each fixture does not need a vent because they are within "X" inches of the drain/vent stack.
Your second sketch is OK because the upper bathroom drains below the lower bathroom (but maybe insert expert advice here to make it better)
Your third sketch that explains how a 1st floor sink drain might need to enter a 2nd floor bath drain due to wall cavity clearance will or will not work because....

Instead I get a generic picture that I have already seen and it does not answer situation specific questions I have. I also get a nice helping of snarky that has no value.



I'm not trying to be rude, just honest. There is no desire to be helpful here that I can see. It is a place to make jokes and feel better than people like me trying learn and make sure I know if a job is done right on my house. I'm sincerely sorry I bothered you, I won't waste our time doing that again.

 

[Dana]

Off topic, perhaps, but "...interested in flaming people flaming people for being off topic..."??

Don't think so.

Nothing I've posted was intended as a burn, and I don't take hj's comment as such either.

I personally can't really dive into the nuances of drain design, but the rest of the project. It wasn't intended to derail the thread, but it wasn't intended as snark, only suggestions on how to make any new addition more moisture resilient and efficient without adding a lot of cost. Sure it was verbose- you don't have to read. But taking offense seems bit off base. I'm not quite sure how any of this thread could be read as snark.