need to put drain line through floor joist

[mpanelli]

I have 2x8x12 joists on 16" center. I need to relocate my upstairs toilet drain into the next bay and run a 2" drain through (or around) 3 joists. Can you drill a hole through the floor joists? If so how large can you go?

[jdm]

Here's the Notching and Boring Guide referenced by the Liberry.

In your case, the holes must be at least 2" from the edges of the joist, and no larger than 1/3 the width of the joist. So you can bore up to about 2 3/8" holes in your 2 x 8 joists (which actually measure 7 1/4").

That's not going to accomodate the toilet waste pipe, so you are going to have to either re-route the pipe or beef up the structure. One of the engineers should be able to advise you further.

[cx]

Welcome, mpanelli. please give us a first name to use.

What Jeff said.

Being a tile forum, we'll presume you're fixin' to tile over this floor once you get things moved about. That being the case, your joists are already a bit overspanned, even before you go to choppin' on'em. You'll hafta remedy that situation, too, while your in there.

What's below this floor your working on?

My opinion; worth price charged.

[kevjob]

watch the pitch of that drain, 3 joist is 48 inches away and at that u need 1 inch of drop which will put u into the lower 1/3 rd of the joist and inspectors will not pass that scenario. u can header off then only go through one of the headers nad smae rules apply as joist notching and drilling.

[mpanelli]

Sorry: My name is Mark.
Yes once I get the construction done I will be adding a 3x4 shower, that is not there now. The shower will sit about 2' from a 4x12 header. The floor and shower walls will be tiled with 12" porcelain tile. The living room is directley under the area we are talking about.

Kevjob: what do you mean HEADER OFF. would that be the same as "boxing"?

CX: The area I described is the ceiling, looking up, from the living room. Are you saying that the "deflection" (never used that word until this site) would be too great for the tile? If so what would you recommend? Maybe adding a few more of the 2x8x12s in the area?

Thanks for everyone's help.
Mark

[cx]

Yes, Mark, your floor joists, and the subflooring between them, must have a deflection of L/360 or less for a successful ceramic tile installation (we're assuming you're tiling the floor here, not the shower). That means, for your joists spanning 12 feet, they must deflect no more than 0.04-inches when fully loaded (usually presuming a 300-pound MIL standing in the middle). For 2x8 joists of SYP or Douglas Fir or similar material, spaced on 16" centers, that means they can span no more than about 11-feet. Your milage may vary, of course, but that's a conservative calculation. If your joists are of a lesser material, or not in good condition, or have been substantially altered (pokin' a lot of holes, notching, etc) the allowable span will be less. That's the Cliff's Notes version.

Sistering the joists is one option. Adding a support wall or beam from below is another option - maybe you need a closet along the living room wall? Or a structural bookshelf?

Your "boxing" is likely the same thing as Kevin's "header-off" term. Sounds like it, anyway. Somebody'd hafta draw us a picher to be sure.

And I've gotta take issue with my friend Kevin's fall calculations for your drain: In four feet of run, you'd need a little less than a half-inch of fall to meet specs, say I. Still very tricky to drill big pipe through those short joists for any distance.

My opinion; worth price charged.

[mpanelli]

Thanks CX:
The 2x8s are in good condition, Each one has a 1" hole 6" from the end next to the header so I don't think that will be an issue. The joist that I have to cross with the 3" line is the first joist in from the wall. Not sure if that makes any difference.
Do you think a "STUD SHOE" will help any? or is there another option? I am not even sure if they make them for 3" pipe. I am calling the inspector out for Wednesday just to make sure he will approve what I am planning.

As for adding a structure not a bad idea. But wouldn't work where it needs to be.
Thanks for the help.
Mark

PS I will try to post pics later if I can figure out how.

[cx]

Well, if somebody will 'splain me what a stud shoe is, I'll be happy to comment on its use here.



Go to the UserCP button near the top of the page, Mark, find the Edit Signature button and enter your first name. That'll pewt your signature at the bottom of each post. This thread will be long; my memory will remain short.

[mpanelli]

I cant post a link but I have only found them for 2" and used verticaly.
go to siouxchief dot com and search for stud shoes.
Thanks
Mark

[jadnashua]

The stud shoe will add a little support, but they state right there in the description that it is NOT a substitute for structure. It also provides a protection from driving a screw or nail into the thing, but not any substantial strength.

[cx]

Try it again, Mark, it'll post this time on accounta you have more than ten posts (anti-spam feature we have).

Then I'll remove your last post.

[mpanelli]

http://www.siouxchief.com/Frm_MS.cfm

[cx]

That link just goes to the main page. I searched stud shoes. Said ain't no sucha thing. Link us to the item if you can.

[jdm]

Sioux Chief, like Laticrete only displays their homepage address in the address box for every page on the site. You have to be a bit sneaky to get a link to any page but the homepage.

Here (really) is a direct link to the stud shoe.

And Kelly, it seems like they have a brilliant search engine if it can find "stud shoe" (my search argument) but not "stud shoes" (your search argument.)

[cx]

Good job, Jeff.

Ain't never seen the like of it in all my years.

Answer to your question about will it help any, Mark: No, not really.

My opinion; worth price charged.