Hi there folks. First time owner/builder starting a new ICF project and looking for advice from those with experience regarding some of my design decisions. The picture pretty much says it all. It's a dropbox link so I'll describe it if the image doesn't load for you. [ https://www.dropbox.com/s/l0mxxjit3hnnoi0/Possible%20Cantilever.png?dl=0 ] Wondering if it's possible (advisable) to cantilever almost 7' above a lintel which is 36" in height and covering an 18' span (garage opening) using something like LiteDeck. Given the obvious engineering review/requirement. Has anyone poured a cantilevered litedeck (or equivalent) over a wide span lintel? Should it even be considered? My thoughts about the non cantilevered side would be supported by some size of metal I-beam and the fact that the pour would extend underneath the walls of the floor above.

Link didn't work.

Best to consult a structural engineer about how to reinforce the cantilever. The link worked for me.

Yes, this sounds like a structural PE design job for sure. It is certainly easily doable. Whether it is advisable or not depends on how much money you are willing and able to spend to have it.

You might want to call a place that does prestressed concrete like they use in parking garages. They likely would be able to give you a quote and amount of cantilever with little cost on you. This would give you an idea of options.

We did prestressed concrete for our front porch and our 2 level garage. We paid $14,000 for a 30x40 foot floor that only required an inch skim coat of cement. So our main garage is on the upper level and we drive around to the back to get to the under garage.

https://www.google.com/search?q=prestressed+concrete+garage+floor&tbm=isch&ved=2ahUKEwiY9-vhofzyAhVCja0KHTZDBqwQ2-cCegQIABAA&oq=prestressed+concrete+garage+floor&gs_lcp=CgNpbWcQA1D-IViqKmDmK2gAcAB4AIABnQGIAc8EkgEDNS4xmAEAoAEBqgELZ3dzLXdpei1pbWfAAQE&sclient=img&ei=AG4_YZj3DcKatgW2hpngCg&bih=979&biw=1865&client=opera&hs=WHC&hl=en

This works but please confirm with your EOR:
8" Deck + 3" slab (total concrete depth of 9").
10' span + 7ft cantilever. With 60psf Live Load and 15psf Dead Load and self weight as Dead Load.
1-#4 at bottom of each concrete joist.
2#5 at top of each joist.
No shear stirrups required.

For the beam - 8" wide x 32" deep x 18' long. Tributary width of (7' + 5').
supporting about 720plf Live and 900 plf Dead + self as dl.
2-#8 at 3" off the bottom and 2-#5 at 3" off the top with #3 O-stirrups at 12" o/c.
Again, this must be confirmed by your EOR and is provided for estimating purposes only.

Ok, so I've done more research and I'm now at the point where it might just make more sense to change my intended goals. Those of you with ICF experience will have better insight.

My thoughts are to bypass something like LiteDeck because of the shoring requirements and just go with something like EcoSpan or Metwood.

Staying within the ICF walls and finding something else to cantilever outside of the envelope might be better?

What typically is used underneath an ICF wall where it spans 20+ feet. Some beefy W10x112?

I'm doing the design work myself so I'm trying to discover options both somewhat economical, but more towards the side of efficiency in construction.

Is EcoSpan throughout better than Watkins hangers with standard floor trusses?

Image:

https://www.dropbox.com/s/3zh46lzgy6hq5kf/Composite%20Flooring.png?dl=0

Posted By Baldwin2014 on 13 Sep 2021 05:56 PM
This works but please confirm with your EOR:
8" Deck + 3" slab (total concrete depth of 9").
10' span + 7ft cantilever. With 60psf Live Load and 15psf Dead Load and self weight as Dead Load.
1-#4 at bottom of each concrete joist.
2#5 at top of each joist.
No shear stirrups required.

For the beam - 8" wide x 32" deep x 18' long. Tributary width of (7' + 5').
supporting about 720plf Live and 900 plf Dead + self as dl.
2-#8 at 3" off the bottom and 2-#5 at 3" off the top with #3 O-stirrups at 12" o/c.
Again, this must be confirmed by your EOR and is provided for estimating purposes only.

Thanks for the confirmation of possibility! @Baldwin2014

I don't currently have an engineer on this project yet as I'm in the design phase and doing discovery about what will work best given the plans I'm putting together.

All feedback is welcomed as I don't know of anyone in my immediate area, in the middle of South Carolina, who is building ICF homes