I just received a plan for an addition to bid on – it calls for two lvl’s to be cantilevered at a corner, then attached to each other. In other words the two walls under the beams stop and then a diagonal wall connects them together. The two lvl’s are on top of the stud walls but then keep on going until they meet in the corner to form a square area for the floor above. So we have two beams meeting in the corner with no support under them.
I know this can be done with steel and maybe dimensional lumber, but somewhere I remember hearing that lvl’s cannot be cantilevered. Am I right?
Also, don’t all codes require a garage floor to be lower by 4″ than the adjoining living space?
Bob
Replies
Bob , The cantilevered lvls are no problem just make sure they are run back better than 2/3 the distance they are cantilevering.
As far as the garage floor goes here in Ill. we have to drop the garage slab 6" from top of foundation to form what they call a "gas curb"
The idea being that any fumes from autos or flammable materials in the gatage don't seep into the house where a hot water heater or furnace could ignite them.
It's I-joists that you don't want to cantilever.
Excellence is its own reward!
LVLs can, in fact be cantilevered. But the back span generally must be about twice the cantilevered distance. Otherwise you have uplift problems to deal with.
Did an architect or engineer call out the LVL sizes and cantilevers? If not, it might be well to run the situation by the manufacturer and see what they say. (CYA)
And Piffin - I-joists CAN be cantilevered also. Every manufacturer's literature I've seen has allowances for cantilevers.
The "gas curb" thing is hit and miss, from what I've seen. Some places have it and some don't.
Never go to bed mad — stay up and fight.
"And Piffin - I-joists CAN be cantilevered also"
I knew that Ron, but what I said was that you don't WANT TO.
Reason being is that it takes so much extra detailing to make it right that it gets rediculous. Better to avoid it by other materials or design, IMO.
Excellence is its own reward!
Yes, you can cantilever but make sure you size the LVL's properly for the loads and the cantilever distance.
The IRC code does not require a dropped garage slab.
could it be fire code? instead of building code.
Anything relating to fire code in my area is part of the building code for residential const. Commercial const. gets into it more with sprinklers, exit lights etc. The IRC code does not require 5/8" rock on the garage/house common wall either, standard 1/2" is OK. I think I'm going to stick with 5/8" though.
Bob...you received plans...I assume from an architect, and your checking in this forum to see if they are copacetic? Although there are some knowledgeable people here, Id trust what was drawn.