Quote:
Originally Posted by 908/930
If bolting direct into the joist I would use 3/8 RSS Structural screws, should be available by the piece at a lumber store vs lag bolts. But, about the extra 150lbs on each joist you are possibly pushing your luck a little there, I'm sure you do not want to open the ceiling but doubling up another 2x8 is probably a good idea. Where is the load in relation to the ends of those joists? What is directly above the location you are installing this?
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The joists are 2x10 (nominal). Actual height a little over 9”. Spaced 16” on center. (This is a 110 y/o house, I can’t ever assume standard sizes or spacing.)
The joists are about 12’ long span. Don’t know wood type, whatever they built from in Portland Oregon a century ago - old growth fir or redwood? The load described below is from about 2’ to 8’ along the span, measured from the exterior wall.
Directly above is a clawfoot tub. Hmm. Suppose 350 lb water, 500 lb humans (I dunno, two big people standing in full tub?), 300 lb tub, 400 lb hood, 100 lb other, that’s 1550 lb live load, area 12’ x 3’ (span plus three joists?), so around 45 psf live, say 10 psf dead, a span calculator says L/600 deflection is 12’.
I don’t know if that’s acceptable deflection in a modern house, but in this old place as long as the deflection is “on the charts” I feel content.