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Discussion Starter · #1 ·
I am wondering if the holes the plumber drilled in my 2 x 10 sistered floor joists damaged them structurally. Some of the joists are sistered with 2 x 6s so I would have flat surface for new plywood subfloor.

These are 3" pipes. Three holes are 3 1/2", and the other is 4". Is there any way to strengthen around the holes?

Thanks for any replies!
 

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Where the hole and how big it is in the span is critical. I would guess that you need to add another joist. If these holes are mid span they are more critical than if on the ends.

This is something the contractor should have mentioned before he drilled the holes !
If you have not paid him off DONT
 

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Discussion Starter · #8 ·
Those are borderline O.K., as stated before, length of span, location of hole matters. I do like that product Nealtw linked.
I think that will be the way to go. I may have to reroute some of the Pex lines so steel supports can be installed around holes. As far as joist span (and joists go farther than this), there's about 8' between the concrete block walls the joists sit on. I worked hard, too, to sister the joists just to make them stronger. Ends of sister 2 x 10s sit about 2 1/2-3" on concrete block.
 

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Discussion Starter · #9 ·
Nealtw: Sir, since the joists are sistered, can you tell me if one metal support plate per joist hole will suffice? Or do I need a plate on each joist?
 

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Discussion Starter · #11 ·
Thanks! Not bad at around $60 each. I'll just have to be especially careful installing each plate. Reason I sistered was just to strengthen and have flat surface for subfloor. Other joists under cast iron tub were sistered, but plumber did not drill 3 1/2" holes in them.
 

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Thanks! Not bad at around $60 each. I'll just have to be especially careful installing each plate. Reason I sistered was just to strengthen and have flat surface for subfloor. Other joists under cast iron tub were sistered, but plumber did not drill 3 1/2" holes in them.
So if all was well with the floor one joist should have been enough so I would say making one strong enough should be enough.
 

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Those are borderline O.K.,
How is a 4" hole in a 2x10 OK ?
And actually, I have to question if those are 2x10's. If that last photo is a 4" hole, sure looks like the hole is more than half the height of the joist

 

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Discussion Starter · #14 ·
They are 2 x 10s. I installed them. You just can't see top of board for that insulation. Plumber cut holes, but I know they need to be strengthened. I can make more precise photos.
 

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I am missing a couple of items. First, what is the span of the joists in question, e.g. distance from one support to the next. Second, if you have already sistered the 2*10 with 2*6, they are no longer 2*10 but something stronger....leading us back to question #1, span. big difference between a 2*10 with maxed out span of around 15’ and one with span of 6-8’.
 

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Discussion Starter · #16 ·
Span of joists is 8' from top of one concrete block wall to another. Image 2040 shows (2) 3 1/2" holes drilled in a 2 x 10 sistered with another 2 x 10. Images 2038 and 2039 show two holes (large one 5", smaller 3 1/2") cut in same 2 x 10 joist which is sistered with a 2 x 8. Image 2037 shows 3 1/2" hole cut in yet another 2 x 10 with 2 x 8 sister. Large hole in photo 2039 close up has 2" between hole and top of joist to hole and 3" from hole to bottom of joist.

Smaller hole in image 2038 has 2" clearance from top of joist.

In image 2040, there is 3/4" from one hole to bottom of joist and 1" to bottom of joist on other hole.

In image 2037, there is 2" clearance to top of joist and 4" clearance to bottom of joist.

Where I used 2 x 8s, they are mounted flush with tops of 2 x 10s they sister so I would have a good flat surface for subfloor.
 

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Discussion Starter · #17 ·
Just a thought...Since clearance between holes and joist edge in image 2040 above is 3/4" on one and 1" on the other, what if I sistered the extreme hole cuts with 2 x 12s, notching them back to 2 x 10s only where they sit on the concrete walls? Sure, I'd have to shim the other joists 2" for even drywall ceiling, but I'm wondering if this is the safest bet. Current distance from floor to joists above is 7' 7".
 

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Just a thought...Since clearance between holes and joist edge in image 2040 above is 3/4" on one and 1" on the other, what if I sistered the extreme hole cuts with 2 x 12s, notching them back to 2 x 10s only where they sit on the concrete walls? Sure, I'd have to shim the other joists 2" for even drywall ceiling, but I'm wondering if this is the safest bet. Current distance from floor to joists above is 7' 7".
Our min ceiling eight is 80" some places it is 84" so 91" should be fine.
 

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Discussion Starter · #19 ·
I remeasured from floor to ceiling-92" with 2 x 10s. So I figure sistering with a few 2 x 12s, including 1/2" thickness of ceiling drywall, would put distance between floor and finished ceiling right at 89 1/2". Ceiling in adjoining large room is right at 90" off the floor.

I would only need two pieces, about $33 apiece. I would have to notch one 2" deep close to wall to clear pipe, and notch each one 2" on ends to clear block wall . I think this would bring the joists back into code. I can fix one other joist with joist repair plate because it says holes can be no closer than 1 1/2" from edge to bring joist back into code compliance. Hole where I want to put plate is 2" from top of joist. It's a lot of work, and I will have to cut the new plumbing and reattach it with couplers after drilling holes in 2 x 12, but I think it will be safe then.
 
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