Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

decks

JStructsteel

Structural
Aug 22, 2002
1,438
IBC really has nothing on decks. For a multi story deck, is the preference to use full height column, and secure the ledger beam to the column, or notch the column? 4' x 8' decks up an apartment building.
 
Replies continue below

Recommended for you

Unless you are using engineered columns, a standard 6x6 will not be straight over that length.
 
Full height columns are difficult beyond two floors, and even then you're limited in your connection options - bolting the girder to the side of the column is a pretty terrible detail for long term reliability.

I prefer to break them at each level.
 
Full height columns are difficult beyond two floors, and even then you're limited in your connection options - bolting the girder to the side of the column is a pretty terrible detail for long term reliability.

I prefer to break them at each level.
What does that detail look like?
 
Depends on the framing. Preferably the joists sit on the beam, so the beam is notched into the top of the lower post. Then the upper post sits on top of the post below boxed in with joists on either side and blocking. If needed for lateral loads, you can set a drift pin between the two posts. For uplift, either strap it or epoxy the drift pin in place. Simpson has some values for their 3G (I think) in wood for their black plastic bases that use a drift pin.
 
I have not seen one in a while, but I thought that some of the Northeast USA cities (Boston, New York) had deck building codes and recommended construction details. I thought I had saved one on my computer, but I'm not finding it now. If those exist, then they could be a good source of details for you.
 
I found one.... City of Chicago (i was geographically close)... This might have some details you can use.
 

Attachments

  • City of Chicago Deck Porch Guide.pdf
    1.2 MB · Views: 20
Depends on the framing. Preferably the joists sit on the beam, so the beam is notched into the top of the lower post. Then the upper post sits on top of the post below boxed in with joists on either side and blocking. If needed for lateral loads, you can set a drift pin between the two posts. For uplift, either strap it or epoxy the drift pin in place. Simpson has some values for their 3G (I think) in wood for their black plastic bases that use a drift pin.
This is how we design 99% of multi-story decks. Beams on the side of a post like a ledger are a disaster long-term. We'll also invert column caps to use on the bottom of the upper post for a better connection if needed.
 
Really can't say I like that one. I know it looks like it should work in theory and does match up to the theoretical model pretty well with all the pins aligned, but that feels a bit unstable to me. The HUC hanger straddling a butt joint in the post seems pretty sketchy. And you're essentially counting on the weak axis bending of the beam to establish continuity in the post.
 
Depends on the framing. Preferably the joists sit on the beam, so the beam is notched into the top of the lower post. Then the upper post sits on top of the post below boxed in with joists on either side and blocking. If needed for lateral loads, you can set a drift pin between the two posts. For uplift, either strap it or epoxy the drift pin in place. Simpson has some values for their 3G (I think) in wood for their black plastic bases that use a drift pin.
Something like this?
1744290671373.png
 
It hardly needs to be said, but these details are pretty flimsy during construction. See below example of something similar.

1744306107459.jpeg
 
Yep - never notch more than half the column, and don't notch in two directions.
 

Part and Inventory Search

Sponsor