@gromicko, can you send these graphics back to the art department for correction? Both of them are incorrect. The maximum overhang/cantilever is 1/4 of the beam span from bearing point to bearing point, not 1/4 of the overall joist length. Thanks!
@gromicko, can you send these graphics back to the art department for correction? Both of them are incorrect. The maximum overhang/cantilever is 1/4 of the beam span from bearing point to bearing point, not 1/4 of the overall joist length. Thanks!
Nope. Our images are correct. It’s 1/4th the overall joist length which is the same as 1/3 the beam spam.
Please read through this post…
https://forum.nachi.org/t/maximum-deck-joist-cantilever-l-4/214046
For more than 60 years it has been called the “One to Three Rule.” The “One to Three Rule” is in dozens of articles in JLC, Fine Home Building, etc. Cantilever can’t be more than 1/3 of the span.
But if that’s wrong, then the rule of thumb’s title has been wrong for 6 decades, correct?
What would be “1/3” then? A third of what?
I agree with you though, DCA6 does not use a 1:3 ratio. It is using 1:4. Since 1:4 is more restrictive, I’m going to have the images adjusted.
Thank you Ryan.
I’m not sure. Like you said, the 1:3 ratio is widely believed to be correct. That’s why I had to study the DCA6 picture and eventually post about it because I initially wasn’t trusting my own interpretation.
I can only assume it was tightened up somewhere along the line and I wouldn’t doubt if we get some push back if reporting on a violation using the 1:4 ratio unfortunately. But unless the DCA6 is incorrect, I don’t see how it could be interpreted any differently.
I guess we need to retitle the rule of thumb too.
Anyway, I have the graphics being modified. Thank you.
Updated this one: Maximum Deck Overhang - Inspection Gallery - InterNACHI®
And this one: Maximum Cantilever - Inspection Gallery - InterNACHI®
I don’t want to get into a pissing match because I have respect for Internachi and its members. I just want to add some food for thought. In NJ we are always told we are not code inspectors. I just happen to have been one for 30 years prior to becoming a home inspector. However, even though I am a licensed code inspector, I do not quote code requirements or code violations. I do include safety issues. In NJ the codes change every few years so many homes built to the code in effect often become a nonconforming issue in a revised code addition. As far as the cantilever, if there is a deck that is not conforming to the code, it could have been designed by a design professional such as an engineer or architect. If that is the case, the designer can exceed the code requirements for structural issues as they are the designer and take full responsibility by sealing the plans. If a deck in question is found to be nonconforming or a code violation, did the home inspector check the plans on file with the local code office to see what was actually designed? In NJ if a home owner designed his own home they must be comply with the code in effect which shows the 1:4 ratio. The requirements may be different in other states as NJ uses the ICC but with amendments. They have a NJ edition of the code.
I’m completely comfortable calling out things I know will not perform, may cause further damage or are safety issues based on my experience and education. It is my opinion they are paying for not code compliance or compliance with a set of plans I’ve never seen.
Even if the seller pulled out a set of plans, I doubt my opinion would change on most of the defects I call out on decks.
Sounds like my entire house. My local building department basically stayed out of my way and only confirmed that what I built was the stamped plans I submitted.
Who signed off on it, SafeSite or ProCode? That’s all those idiots do. LOL. Right, wrong, or indifferent, if it somewhat resembles the plans, they sign off on it…
My engineers stamped it and that was good enough for my county. It’s an insane home.
I agree on that. If the seller produces a set of plans that shows the item in my report was designed and approved by a qualified professional, that is terrific actually. I raised awareness of a potential issue, the seller provided documentation it was OK, and I have no liability if it fails in the future. Win, win, win.
Perhaps that is why we see so many failed decks in the news!!
(Yeah, yeah… I know)!
The reason I made the comment was because when I was a state building inspector I was challenged by a contractor and on more than 1 occasion and we ended up in administrative law court and lost. I drove 2 hours to get to court and lost. The judge stated I was code expert and not a design professional and they can exceed the code requirements. I have also been to the construction board of appeals for similar items. However, I do mention issues that I find but I refer them to check the plans at the local code office. In NJ they can do that if they fill out an OPRA(open public records act) request. This went into effect after 911 attack in NYC. If they decide not to do the research, thats on them.