Check out some similar questions!

scirocco70 · Aug 10, 2007, 04:46 PM

Heya folks...

What is the minimum practical vent size? I know most codes call for no smaller than 1.5", but what's the real minimum? It's just air.....

I'm (eventually....) putting in a basement bath with either a traditional sewage ejector or a macerating ejector (Sani-Grind).

The SaniFlo only calls for a 3/4" ejector line, but a 1.5" vent line. It also indicates 18' maximum of vent line, which obviously won't work to vent-to-roof in a two-story house.

Here's some links, the installation diagram is on page 14 (or 16) of the PDF.

Sanigrind macerating (grinder) pump for standard bottom outlet toilet

http://www.saniflo.com/downloads/ins...onsE_Nov05.pdf

SO. Anticipating that 1.5" really is the smallest usable vent size, is it acceptable to bore a hole through the sole plate of the first and second floor, as well as the top plate in the attic to run the line? Is there a decent way to do this WITHOUT ripping up all the wallboard along the way?

Thanks again, for all the help I've gotten here!

~aaron

doug238 · Aug 10, 2007, 05:14 PM

The minimum size vent is 1 1/4" but that material costs more and is not readily available, that is why we use 1 1/2"
Open the drywall so you don't cut a wire and catch you house on fire.

scirocco70 · Aug 10, 2007, 05:59 PM

So, being that I know more about plumbing than framing at this point (which should indicate just how little I know about framing... ) is it safe to bore what amounts to a 2" hole (for 1-1/2" pipe) through the 3.5" horizontal framing members?

Is there any sort of bracing or typical reinforcement that needs to be done? I'm looking for best-practices here.

And, I'll be REAL careful not to burn the house down, even though homeowners insurance DOES cover rampant stupidity. ;-)

~aaron

doug238 · Aug 10, 2007, 06:05 PM

you may not cut or notch a floor joist or ceiling joist. You may not bore anywhere but within the middle 1/3 span. You may not remove more than 25% of a floor or ceiling joist. Ex... a 2 x 9 is 8" wide. you may not remove more that a circular hole more that 2 1/4".
for a stud in a non bearing wall, you must leave a minimum of 1/2" on both side surfaces.

scirocco70 · Aug 10, 2007, 06:16 PM

Thanks!

I don't mean the joists (or even the studs), since I can run the line vertical all the way up to the attic...

I'm worried about the sole-plate and head-plate (is that what it's called?).. i.e. the 2x4 that's laid flat across the joists, which the studs rest upon. The head-plate (?) being the 2x4 that's laid across the top of all of the studs in the wall.

I'll open up the drywall the whole way, and the run will be between the studs, straight up.

BTW, I'm doing all of this myself because all three of the plumbers I called for bids never got back to me... either I'm too picky, too inquisitive or I look like too much of a pain in the to them. That's probably because I generally insist on doing it REALLY right, above and beyond the requirement. For example, I've done all of the main drain work in cast iron, because it's quieter and stronger.

scirocco70 · Aug 10, 2007, 06:16 PM

Thanks!

I don't mean the joists (or even the studs), since I can run the line vertical all the way up to the attic...

I'm worried about the sole-plate and head-plate (is that what it's called?).. i.e. the 2x4 that's laid flat across the joists, which the studs rest upon. The head-plate (?) being the 2x4 that's laid across the top of all of the studs in the wall.

I'll open up the drywall the whole way, and the run will be between the studs, straight up.

BTW, I'm doing all of this myself because all three of the plumbers I called for bids never got back to me... either I'm too picky, too inquisitive or I look like too much of a pain in the to them. That's probably because I generally insist on doing it REALLY right, above and beyond the requirement. For example, I've done all of the main drain work in cast iron, because it's quieter and stronger.

speedball1 · Aug 11, 2007, 09:27 AM

The Standard Plumbing Code will allow a 1 1/4" vent for only two fixture units.
You may vent a single lavatory or a single kitchen sink with a 1 1/4" vent. A 1 1/2" vent will allow 8 fixture units which will allow you to vent a bathroom group consisting of a toilet, lavatory and a tub/shower,(6 fixture units).
We run our vents at 2" which will vent 20 fixture units. This will include most bathroom groups. Our inspectors are happiest with 2" vents. Good luck, Tom

doug238 · Aug 11, 2007, 01:47 PM

For a stud in a non bearing wall, you must leave a minimum of 1/2" on both side surfaces. For the top plate or the bottom plate you can get away with cutting them completely. The floor will carry the load on the bottom plate and you can put metal straps to hold the top plate.