"notched" joist deflection advice needed

[mothersagainstnoise]

hi im max. a newbie.

i have a joist situation that will not compute in your deflecto calculator. here is the situation.

12 foot span. 20" o.c.'s , want to use 2x12's with one end in brick and the other end notched to fit in an iron I beam. the notched end of the joist will be 7" just for the portion sticking in the I beam. will this rig suffice for laying a full tiled floor and walls for big shower. no deflection??

thanks for the advice in advance, experts.

[muskymike]

Hi Max, welcome! I think that it would be ok if you when closer with the joists like 16", but I aint not Injuneer, I'll ping some one that would know for sure.

[cx]

Welcome, Max.

If you're fixin' to cut all that notch out of the bottom of the joist, you're not within standard specs leaving only 7" of a nominal 2x12.

I'd rather see you use 2x10s spaced on 16" centers instead. That gives you a little less rigidity in the structure, but keeps you well within the required L/360 deflection requirement for ceramic tile and within the notching guidelines for the joists. That also gives you closer joist spacing for your subflooring, which is the bigger concern for tile installations anyway.

If you just want a more rigid floor, or if you plan to use natural stone tiles, you could space the 2x10s on 12" centers, giving you less joist deflection and even less spacing for your subflooring.

Ain't no such thing as "no deflection" in a wood structure, by the way.

My opinion; worth price charged.

Oh, and MMike was fixin' to ping a real Injineer for ya, but got me instead. I'm not a real Injineer, but I do play one on some local jobsites.

[mothersagainstnoise]

thanks for the help.

the I beam is our limiting factor though. the joists have to remain inside the I beam. 7.5" max! but the other wall is brick, any size.

how about two 8x2's sistered with 16" o.c. spaning the 12'?? would this hold the weight of a very large walk in tiled shower?? and deflection ok?? sistering with bolts on 8x2's ok?

[bbcamp]

2 2x8s every 16 inches will be fine ceramic tile in your bathroom, shower and all. You'll need to space them on 12 centers for stone.