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Old 12-27-2013, 08:14 PM   #16
Bodie Powers
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Quote:
Originally Posted by Louis
Alternatively, would it be within code to have one or two of the existing light junction boxes do double duty and provide a junction box for these wires?
Yes, but with limits. There are code restrictions on the number of conductors allowed per cubic inch of box. It is common, and I have done it numerous times, to use an existing switch, duplex, fixture box as a convenient splice box.
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Old 12-28-2013, 09:31 AM   #17
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Originally Posted by Bodie Powers
Yes, but with limits. There are code restrictions on the number of conductors allowed per cubic inch of box. It is common, and I have done it numerous times, to use an existing switch, duplex, fixture box as a convenient splice box.
Bodie,

Couldn't I just replace the junction box with a larger box to address this code issue?
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Old 12-28-2013, 09:32 AM   #18
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If that's at all convenient, yes, you could certainly do that.

My opinion; worth price charged.
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Old 12-28-2013, 09:51 AM   #19
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We is having us one of them failures to communicate, Louis.

I put some of that post in bold on accounta it looked like there might be some misunderstanding before. I'll give it another try with the part you appear to be overlooking in even bigger bold.

To reduce the joist deflection you must sister an absolute minimum of the center two-thirds of the joists.

It matters not at all where your tile installation will be over the joists, to decrease deflection you must sister the center portion of the unsupported span. If you can't do that, you gotta go to plan B.
CX,

Indeed, I did misread.

I now understand what you are saying but I'm not fully understanding the physics hence why I was misreading. Seems to me that sistering the floor joists under the tiles will shift the deflection to the portion that is not sistered. Why wouldn't that be acceptable?

More importantly, if I go with porcelain tile rather than marble, which is what I've been planning from the start, seems like I'd have plenty of leeway. My existing floor gives me a deflection of L / 337 according to Deflecto. I wouldn't expect to need much additional support to get to the minimal requirement of L / 360 for porcelain.

As you can see in the pictures in the beginning of the thread, the floor was originally tiled. I believe this tile was original from 1960. If you look closely at the second picture, you can see a crack in the lower left corner. It is a bit out of focus. This crack runs parallel to the floor joist from the outside wall to the hall. The subfloor was 1/2" ply, covered with tar paper, wire mesh, and 1" to 1.5" mortar.

If deflection was a problem in the existing floor, wouldn't you expect to see a crack perpendicular to the floor joists?
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Old 12-28-2013, 10:26 AM   #20
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Louis, it's your house and you're free to tile over whatever structure you are comfortable with. We can only tell you what the industry standard requirements are for a given application.
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Old 12-28-2013, 10:54 AM   #21
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Louis, it's your house and you're free to tile over whatever structure you are comfortable with. We can only tell you what the industry standard requirements are for a given application.
CX,

I'm hoping for some risk assessment.

I only need to get to L / 360 from L / 337. I imagine some would say that L / 337 is good enough.

Placing the sisters in the middle 2/3rds is going to require some major work ripping out sheet rock in the room below.

I'll do it if I have to but I can't help but think it is is overkill.
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Old 12-28-2013, 11:38 AM   #22
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Placing the sisters in the middle 2/3rds is going to require some major work ripping out sheet rock in the room below.
Why would that be the case? ....just curious.
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Old 12-28-2013, 01:03 PM   #23
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Originally Posted by Bodie Powers
Why would that be the case? ....just curious.
Bodie,

As I understand this it means I'd have to run 7.66' ft sister centered over my 11.5' floor joists (11.5x2/3=7.66) leaving just under 2' on either side. As the bathroom is only 7.5' long, the end of the sister will have to extend under the hallway about 2' to center it on the span.

I'm thinking I'll have to remove the ceiling sheet rock from underneath to attach the sister. "Maybe" I can reach from above without removing the sheetrock but then there are still those wires not to mention wrestling a 2'x8' into place that is longer than the clearance.

If I'm missing a better way to get this into place, please let me know. I'm sure you guys have all kinds of tricks that you learned through experience.
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Old 12-28-2013, 01:31 PM   #24
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Held flat and at an angle, those joists should slip in easily from inside the bathroom. Once they're in place, then tip them up with the top in place, and carefully hit the bottom with a sledge hammer to get it over against the existing joist. Shaving a slight recess, maybe 1/4", with tapered ends at any intervening bearing walls will assist in getting it stood up, then just shim it tight over the wall when you get it where you want it.

You can predrill some holes for deck screw down there at the end, run the screws in a bit, then reach in and screw it tight once it's in place.
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Old 12-28-2013, 01:35 PM   #25
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Louis, Deflecto is conservative...I believe it uses 50 lbs dead+live load vs 40lbs industry std....something like that. Suffice it to say there's some wiggle room. I'm not smart enough to speculate on odds of success with a 337 rating and porcelain.

My local code allows electrical splice boxes inside cabinets (back/side wall), and inside closets, as long as accessible. Looking at your proposed design, could you place a splice box next to the toilet, beneath the window? And what's that space adjacent to the tub, on the same wall? Looks like a closet or makeup vanity? Could you place another splice box in that location? Would the cut wires reach? If you can do something like what I've described then the wire problem is solved.

As for the sister extending nearly 2' into the hallway space.....have you laid on the floor to see how far into that space you could reach with a drill? I'm guessing you can make this work.
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Old 12-29-2013, 03:02 PM   #26
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Louis,
I'm not a pro, but I see something.
Does your drain running through the joists meet the notching and boring guidelines? That reduces deflection.
If your gonna splice the wires, your gonna need some slack in them, not accounting moving them to a fixture box.
As far as dropping the ceiling. Remodeling often makes you open up more than you intended.

Just some thoughts, keep us posted.
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Old 12-29-2013, 05:48 PM   #27
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Louis,
I'm not a pro, but I see something.

Does your drain running through the joists meet the notching and boring guidelines? That reduces deflection.

If your gonna splice the wires, your gonna need some slack in them, not accounting moving them to a fixture box.

As far as dropping the ceiling. Remodeling often makes you open up more than you intended.

Just some thoughts, keep us posted.
Hi Mark,

I will end up removing some of the first floor ceiling as a result of past water damage but I'm trying to keep it to a minimum. But like you say, I almost always end up doing more than I started out to do. Aside from my labor, sheet rock is the cheapest part of the job.

Regarding 'notching and boring guidelines,' I have no idea what is acceptable. The pipe is 1.5" copper. Holes are a bit oversize.

I've been giving some thought to splicing the wires and where I might put the junction boxes. As there will be a vanity on one side and a closet on the other side, I could probably hide the junction boxes 'in the vanity' and in the closet. Additionally, there is a closet on the other side of the tub that would work and the space behind the toilet may remain open by a service panel to the master bathroom. My next project is the master bath and I'm planning on putting in a steam shower. The steam machine would go here and would require an access panel. I think I could also have junction boxes in here as well.
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Old 12-29-2013, 06:03 PM   #28
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Easy enough to find accessible places for junction boxes, Louis, but are you keeping in mind that your existing wires must be able to reach these places?

If those joists are nominal 2x8s, the maximum bore would be about 2 3/8ths" and it'd hafta be pretty well centered to maintain the required two inches from either edge.
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Old 12-29-2013, 06:18 PM   #29
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Easy enough to find accessible places for junction boxes, Louis, but are you keeping in mind that your existing wires must be able to reach these places?
Yes, I've considered that. If I can't 'pull' the existing wire, I'm assuming any splice will require two junction boxes - one at each end of the room.

Quote:
If those joists are nominal 2x8s, the maximum bore would be about 2 3/8ths" and it'd hafta be pretty well centered to maintain the required two inches from either edge.
The bore is 2.5" and not centered. So what does that mean for my project?
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Old 12-29-2013, 08:06 PM   #30
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Gotta slit your wrists and bleed out. No other option.

There's just not a hellofa lot a fella can do in situations like that except to provide additional support under the joists if that's feasible. Otherwise you just hope that's a really nice joist and manages to remain sufficiently rigid, I suppose.

Looks like it's too close to the holes for the wiring, too. Maybe the utility knife really is the only option.

My opinion; worth price charged.
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