Can slope be less than 1/4--do you ever "push it"?

[DavidTu]

Help: have to choose lesser of two evils slope or structure....

2x8 joist space coming off tub drain we have 1-1/2" CI ptrap as high as possible with plastic street sanitee going direct into ptrap via 1-1/2x2 Fernco proflex coupling. windows in wall below so running horizontal in joist space thru 2x8 header heading off a joist to make room for tub drain. Didn't want to run thru header twice (maybe wrong decision)--once for drain, once for vent) so vented to wye on horizontal before the header on an (honestly) not quite 45-deg roll. This vent wiggles thru two 45s making back to the wall. To keep these fittings at or below floor level determined my altitude for the run. After wye to vent, it runs about 5' to 90 horizontal turn (combo connecting into shower and laundry 2" horizontal line) and thru joist. This is where we get in trouble on slope. Choosing to keep the run thru 3 joists (2.5" hole) above bottom 2" of joist as per code and to keep structural integrity has put my entire slope after header less than 1/4" & at points just over 1/8"--going by 8" torpedo which is all will fit in there. This is all in 2nd floor joist so in the end there is a nice drop into 3" pipe going to basement, in case that helps.

Holes are already done, of course. Now what? Better to live with less slope or at this point to make the joist holes worse than they had to be by not only getting within bottom 2" mid span but now also making hole larger than allowable 2.5"(to gain slope) and thus also violate code to bore no more than 1/3 depth of joist (these are ancient actual 7.5" joists btw)??



^^^This is the tub drain, ptrap, wye to vent and thru joist header.

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^^^You can see that the first hole is already a bit enlarged, had 1/4 slope coming across but pulled it up higher for cross-joist run.

 

[Leejosepho]

Choosing to keep the run thru 3 joists (2.5" hole) above bottom 2" of joist as per code and to keep structural integrity has put my entire slope after header less than 1/4" & at points just over 1/8"--going by 8" torpedo which is all will fit in there. This is all in 2nd floor joist so in the end there is a nice drop into 3" pipe going to basement...

As long as the line is well-strapped or whatever to assure it has no sags, that slope would not concern me.

 

[Sponsor]

 

[NHmaster3015]

There's not an inspector in the world that would pass that. The slope needs to be 1/4 ipf and those holes are larger than the 1/3 of the joist requirement and that 1/3rd needs to be in the middle of the joist.

 

[Dj2]

What's in the photos is wrong and will fail inspection.

 

[Craigpump]

Why would you use band clamps?

Do they even meet code when buried behind Sheetrock?

 

[Cacher_Chick]

The banded clamps ARE appropriate for use with cast iron pipe.
The problem with lacking pitch is that the pipe does not self scour properly which leads to a clogged drain.

Structurally, the only proper thing to do would have been to NOT drill any holes in the joists, but to run the piping below them.

 

[Terry]

If the floor joists are 2x8 are smaller, I won't run waste lines through them.
I like to run with the joist, and if I need to cross, I drop below, perhaps near a wall so it's not so obvious. You will notice many homes have hallways with lowered ceilings, conceiling all kinds of things. Pipes, Ducts, gas lines. ect.
Or the corner of the room may be boxed in. When I was building homes, just to look like I intended to do it, I would box down the four walls, even though I only had pipe and ducts along one wall.

 

[DavidTu]

There's not an inspector in the world that would pass that. The slope needs to be 1/4 ipf and those holes are larger than the 1/3 of the joist requirement and that 1/3rd needs to be in the middle of the joist.

It is meeting engineering spec now b/c 2.5=1/3 of 7.5 And bottom of hole is 2" above joist bottom. That's why we have slope issue. Question is do you increase slope and then dip below 2" from edges with holes a little > 2.5" OR do you live with slope under 1/4"? Its actually just under 1/4" for most of run. Going under joist is not an option.

Sounds like you guys are saying no wiggle room on slope.

 

[Terry]

What is your total drop in that distance?

 

[DavidTu]

Overall to turn its 40" length from header and 3/4" drop. From there its (now) another 40" with only 1/2" drop. First part I suspect you'll say is just barely ok. After turn it is too shallow.

Btw, forgot the pics were a bit old so you guys don't see rest of run after turn where holes are clean--those were the ones I was saying were ok. The hole thru header and at turn where had to make banded coupling work we will put steel straps below. So, yeah those two holes are sh*t.