cantilever floor joist

[paul s]

2 x 6 syp no. 1   16" oc  10 lb dead load, 40 lb live load  how far can it be cantilevered?

2 x 8 syp no. 1   16" oc  10 lb dead load, 40 lb live load  how far can it be cantilevered?

thanks a bunch

[MountainDon]

Cantilevered as in on both sides of two beams that support a small cabin such as in the Little House plans?

Or as in a bump out or a small deck/balcony?

[paul s]

Cantilevered as in on both sides of two beams that support a small such as in the Little House plans

[psammy]

a good rule of thumb is that a load bearing cantilever should not exceed the depth of the joist, so 5.5" or 7.25" in your case.  generally 24" for a non load-bearing cantilever, but probably would limit it to 12"-16" with 2x6's.  YMMV.

psammy

[paul s]

shat is the joists spacing and cantilever for the little houses?

[John Raabe]

In the Little House plans the joists are cantilevered over the beam and the load is offset by the backspan of the continuous joists. You would not want to do this with a bigger house or heavier load (say 1-1/2 or 2 story). This is done to protect the beams and get them inboard of the walls.

[MountainDon]

There's not been much response to your questions, paul. They is a difficulty in answering.

Here's an analogy that may help explain.

Let's say that friend Jean is a superb baker. She makes deserts to die for; chocolate is her specialty. She writes a small booklet with her recipes. She charges a small fee. She sets up a website to handle non local sales of the bake book. The book sells well. Jean sets up a forum as a place where people can discuss recipes. Not just her recipes but baking in general. Would it be correct to ask for the recipe for her brownies on her forum?


Before I was a moderator and then an administrator on this forum I was an amateur home builder and renovator with several main projects spread over a lifetime and more minor projects than I can remember. When the time came to plan and build our small cabin there were a couple of aspects that I had not dealt with. I had some thoughts, but no real idea. What we wanted to build aligned nicely with the Little House plan set. I bought the plans and learned from them. I also found a couple of the included extras handy to have.

It's not so much that I/we don't want to state what the foundation details are as it simply seems to be unfair to give that away.

Also unlike the available free joist span calculators and charts, there is no off the shelf rule of thumb for the cantilevering as designed into the Little House plan kits. The calculations involved for the cantilevered floor and beams for the Little House plans were passed through an engineering program.

[Sheldondesigns]

Cantilever will also depend on whether this is only a floor load as in an interior balcony or whether it is also supporting the dead load of an exterior wall and also a roof.  If it is supporting an exterior wall, roof load and floor load you will have to add to the loads you indicate.

For example, if your cantilever is at the eave, and your building is 20' wide with a roof load of 40# (30# snow and 10# dead), you might actually have an additional 10' (half building width) of 40#/lf or another 400#/lf at the end.  At the 16" oc joist span that might be an additional load of 532# per joist.  Nothing to sneeze at.  I would have the condition engineered.  It would be very expensive to get it wrong.

[paul s]

back from a few days at a bio intensive growing workshop,  a small part of the workshop delt with housing and gardens to feed the people in the house.  my question about the beams was in relation to this.  I understand mountaindon your side of this and do agree. with you.    I was loooking for an even lower cost housing solution but seem to be stuck at 25 dollars per square foot for rock bottom cost for 1000 square feet here in north carolina.  this is materials only, no site prep or labor.  the  site and prep  and some labor and the the community gardens and "wild areas" raises the price to about 75,000 for the 1000 sq. ft.

thanks

[MountainDon]

And just to be clear, a 1000 sq ft footprint is probably too big to get into cantilevering the joists out over the beams. That is assuming the sq footage is gained by building longer and wider than the Little House designs, rather than just building a longer design (like a 14 x 70.... ugly) . The beams would be best situated directly under the sidewalls as in the 20x30 plans..