Hi,
This is my first posting, though I am a long-time reader of Fine Homebuilding.
I am about to start building my new residence near Daytona Beach, FL. While this home is being built, my family has rented a brand new patio-style home. Besides living in this home, we will be storing our extra furniture, cartons, and tools in this unit until we can move into the new home.
My question has to do with acceptable loading of the floor joists of a second floor bedroom that I want to use as a storeroom. The floor joists of this room span about 24 feet. I have no direct knowledge of the floor joists type or depth.
I believe code requires that the floor joists be designed to support 40 pounds per square foot live load. But, I want to stack numerous cartons, tools, etc., in this room – and leave it in place for many months. Since this unit is brand new, I don’t want to cause any harm.
If I distribute the load uniformly, would anyone care to offer an educated guess as to how much weight I can safely place there, i.e., can I load to 40 lbs per square foot – or should I hold it down to some lesser value? Also, if the load is not truly uniform, I presume it’s best to put the heavier loading near the ends of the joists and less weight in the middle. Does that seem correct?
Thanks very much.
gary comfort
reston, va
Replies
First off, glad ta have you in the forum. Always happy to see a new face.
You're correct in saying that most floors are loaded for 40 PSF. But some places allow 2nd floor sleeping rooms to be designed for 30 PSF.
Since this is a new building, you should be able to get some info from the builder regarding what type of floor system and design loads were used. We really can't tell you much without knowing anything about what was use for your floor system.
Meader's Law: Whatever happens to you, it will previously have happened to everyone you know, only more so.
Books and tools definitely can make for greater than 40#/ft when stacked to the ceiling. Go careful and definitely keep the heavier items near the outsides. 24' is a long span and a lot of these places are minimally designed and built. The inspector was probably looking more closely at the hurricane details.
Excellence is its own reward!
Thnaks for your response. I think my real question has to do with the definition of "Live Load." Am I correct that an assumption with Live Load is that it will not remain in place for a long period. That's my real concern since, if I use this space for storage, I will be leaving loads untouched for months at a time. I think I am really placing "Dead Load."
Is there any rule of thumb for how much one must reduce a 40 psf rating for a Live Load to reach a safe load for a uniformly distributed "dead load"?
Thanks again.
gary
Dead load is the weight of the building material itself. You are adding live load, no matter how long it stays there.
Follow piffin and Boss Hogs advice. They are sage gurus and prolific posters on this site.
BTW, welcome aboard.
Dave
That is an interesting question, but I don't have the final answer for it. I guess I'll have to use a lifgeline and call.
;)
Technically, the live load is anything other than the weight of the building material itself, but I can see how a continued stress might tend to overcome the natural resiliancy of wood to introduce a bow over time.
But my bigger concern in practical terms would be this; The design load is reached by previous testing and certification under ideal circumstances, with allowances calculated in. But we all know that not everybody on every job follows all the directions to a T.
Condoms break and in some places they've had three hundred year storms or floods in the past twenty years. maybe your floor was constructerd by a crew that always goes the second mile with overkill. Or then again, maybe it was built by a schlock in a hurry for monday night football or working off a weekend party.
Are there any storage rental units available around there?.
Excellence is its own reward!
Gary -
24' seems quite a long span for floor joists. Are you sure there isn't a supporting wall below?
In any event, I agree - storing tools and all on this floor would be suspect. If I were to be in your situation, I think I'd tend to stack the boxes, etc., along one or both walls at the end of the joists. Wood floor joists in residential applications (here in WA state using Doug Fir/Larch) are generally designed for deflection rather than shear. Meaning they'll carry more weight on or near the support than at mid span.
If this place has a garage, that would be my first choice, though. The car can sit out for a few months.
Dennis in Bellevue WA
[email protected]
Givern the location, I'm guessing open carport parking in under the building..
Excellence is its own reward!