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khabs · Apr 11, 2015, 06:48 PM

Hi folks. Not sure if this question is for framing or plumbing. I had opened up ceiling to tie in new plumbing and I noticed the existing plumbing is going through ijoist and the opening is full size of the joist .not including the top and bottom plate. Which are intact. Is this OK? I got a permit to add new bathroom but worried inspector will say something about existing opening

speedball1 · Apr 12, 2015, 07:46 AM

Can you take a photo or photos of the area you are questioning and post them to us.Back to you , Tom

khabs · Apr 12, 2015, 01:03 PM

See pic

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Milo Dolezal · Apr 12, 2015, 04:25 PM

Trust Joists "TJI." Sorry to have bad news, but, no, it is not OK to chop up joist like that. There is specific way to penetrate these joists according to manufacturer's calculations.. They also have engineered knock-out holes you can use to run plumbing pipes through. One such a hole is visible in your photo on the left, about 3/4 way up. ( in the photo the hole is not knocked-out, you just see it outlined. It is about 1" in diameter.) Depends who you get for inspector. He may ask you to reinforce the existing joist or just over look it and let it go as existing.

Milo

khabs · Apr 12, 2015, 04:38 PM

Thanks for the info. Now I'm hesitant in even adding the bathroom. Even though this was the original construction (from a reputable builder - DR Horton) I'm now afraid the inspector might say something about this.

Can he require me to do something if this is part of original build that passed inspection (I would assume)?

Milo Dolezal · Apr 12, 2015, 05:02 PM

It really depends. The hole is so large that that particular joist lost its structural integrity.

As I said before, it really depends who you get for Inspector. He may ask you to reroute the pipe under the joist and double up the damaged joist. Or he may ask you to submit to him new engineering calculations showing that damaged joist as not having any impact on structurality of the floor / ceiling it supports. You can always claim it was existing situation and may waived it off.

However, if you plan on drilling additional hole through that joist, I am almost sure he will pay attention to it. Plan on soffits.

Is it only one joist with such large cut out - or does it continue through more joists ?

Milo

khabs · Apr 12, 2015, 05:07 PM

I see few more places with same large hole. What is the hole limitatiob on ijoist? One place I read it can be large as the full web span minus 1/8the inch. I'm not planning on any new holes. The ne plumbing will come down vertically and tie into the location in the picture. The new plumbing is on the 3rd floor. I assume inspector will want to see where it ties in? For new plumbing I'm going through joists bur not planning on drilling more rhan 3.5 inches

Milo Dolezal · Apr 12, 2015, 05:12 PM

This is the engineered diameter of a penetration (a hole) in such joist.( see the white arrows pointing to the outline of the knock-out ). As you can see, it is a pre-cut hole. You knock it out with hammer and lead your pipe through it. They also allow you to cut some additional holes, but they have to be cut in certain, prescribed way. Besides, you never cut through joists with sawzall all the way to the end of the joist.

khabs · Apr 12, 2015, 05:14 PM

Would it be lot of work to reinforce it? Is it basically a new joist? That would be a lot of work. I think I might abandon the bathroom addition. Not worth the hassle if I have to address the joists

Milo Dolezal · Apr 12, 2015, 05:21 PM

I am not a structural engineer. You have to consult with your own engineer or General Contractor. He will tell you what needs to be done. There are few options as to how to reinforce the cut joists. One of them is to double up on each cut joist and re-routing pipes through soffit. Nevertheless, since the ceiling is now open and the hole are exposed, I would deal with it.

hkstroud · Apr 12, 2015, 08:37 PM

See this web site, page 9 Table A & B.

afaroo · Apr 12, 2015, 10:21 PM

Harold your link for the website did not show please, Thanks.

John

hkstroud · Apr 13, 2015, 02:22 AM

Thanks John. That's because I didn't post it. A mind is a terrible thing to lose. Have you seen mine?

http://www.ilevel.com/literature/TJ-4000.pdf

afaroo · Apr 13, 2015, 08:38 AM

Great link, Thanks.

John

khabs · Apr 13, 2015, 04:30 PM

Thanks for the link!

I measured it today and the Full Ijoist is 14inches. According to the link it looks like I can make a 11" hole (which spans the full web).

I think that confirms the current hole is perfectly fine and also explains how the builder was able to pass initial inspection.

Thanks guys!

hkstroud · Apr 13, 2015, 04:42 PM

I tend to agree.

Milo Dolezal · Apr 13, 2015, 05:04 PM

I am glad you were able to figure it out. Good luck with your bathroom addition !

Milo