Floor joist support


I am wonderingif my second story can holda new fireplace. I have 2x10 floors 16 in. on centerwith a 13ft. span. the fireplaceweighs 590lbs. I was placing the unit parallel to floor joist on exterior wall (only choice). I wasgoingto put the unit on a platform that isabout 44 in. deep to accomidate hearth. I wasgoing to finish with fake rock front. I need to build a chase that is 26 in. deep and abou 67 in wide that will extent up to ceiling 12 ft. high. I wasgoig to put blue stone on hearth. I am concerned about the weight what do you think? -------------------------------------
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I think I would "sister" another 2x10 in the area the fireplace is going to be sitting. Might even do a couple of crossbraces too. Truthfully, it's pretty difficult to answer your question without knowing what else is in the room weighing on the floor.
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Floor joist systems do have a "live load" rating. You may look that up in a construction manual, and include the type of plywood you have on the system. I would do that first. Then figure how much (aprx) you are adding to the floor. Being near the wall is helpful but it sounds like you are parallel....not as good. Another helpful part of the evidence you provide is that putting a platform on the joist system, will add weight, but also span several joists, rather than bearing on only one. I would use 2x10s or 1 1/8 ply for joist for the platform and catch as many floor joist as possible....(like a snowshoe-on soft snow) what a dumb example-? Use a good grade of ply on the platform. (3/4 and glue) Adding sister joists (as was mentioned)would work well but how easy is that going to be. john

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The OP is adding a permanent load, which is a dead load. The duration of the load affects the calculation somewhat, and the allowable live loads in most span tables are not based on permanent loads. They're down-rated like wind and snow loads, though not to the same degree. http://www.awc.org/technical/spantables/tutorial.htm
R
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So, he must have to look at the tables for "dead loads" I take it. I assume they have those, unless that would have to be an engineers call.
Like putting a water bed on the second floor or a piano. I do know that most floor loads in the books are always tested high also. I am sure they can take more if need be. john
wrote:

The OP is adding a permanent load, which is a dead load. The duration of the load affects the calculation somewhat, and the allowable live loads in most span tables are not based on permanent loads. They're down-rated like wind and snow loads, though not to the same degree. http://www.awc.org/technical/spantables/tutorial.htm
R
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The tables show only distributed loads, not point loads. Point loads require calculation and won't be in any table. Not only ultimate strength will have to be determined, with a factor of safety of course, but shear and deflection. The deflection won't be a problem most likely. Having the load near the wall minimizes the risk, but if the guy wants to look into it he should do it the right way. That link gives a good overview of how to do it.
R
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OP-
What is the TOTAL weight of the entire fireplace installation? Framing, fireplace insert & all the finishes (rock face)?
If the load is in the 600 lb range .....13 ft span at 40 psf is 520 but you have more like a concentrated load (really a local distributied load)
Just a SWAG but one sistered joist wouldn't be enough, two would probably be ok, three would definitely do it. But to be sure you need to do ( or have done) some calcs. That means....get it looked at.
I'd open up the floor or the ceiling below & sister in the joists.
cheers Bob
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