Structural Bolt Challenge

OK. You inspect a given deck.
You know that people can purchase various sizes of Hot Tubs. Do these different sizes affect the bolt spacing?

If so, why?, If not “why not”?
The equation has only one variable, and that is now set at the joist length of the deck being inspected…

http://www.awc.org/Publications/DCA/DCA6/DCA6-09.pdf

What specifically are you referring to?
Does this adress a proof as to “why” this bolt equation with one variable is OK, if so, please state where, and how.

I think you meant to ask the following: Could increasing the load of a deck by installing a hot tub require the installation of more ledger fasteners? A: Yes.

Posted for your viewing pleasure.

Different Hot Tubs have different loads…Yes do they affect the spacing

That document states within itself that it does not apply to concentrated loads such as hot tubs.

Thank much appeciated…

You could inspect houses for 90 years and probably never see a deck without a hot tub and where a hot tub was never present that was built to handle the load from a hot tub other than maybe a 2-person spa.

As I posted before:
A deck must have a very substantial sub-deck built underneath it that is designed or built by someone who knows about structural loading and construction techniques whenever a hot tub or spa is to be installed that is supported by the deck. In other words, the deck ledger should not be holding up the load from a hot tub.

True…I see alot of them…but, in any case how does this equation address what I asked?

Any other questions I can help with?

The hot tub should not be **added **into the equation as it has its own support. If it does not then it must be designed by a structural engineer which is way above the normal deck inspection. To add more weight to a ledger with a hot tub unsupported is something you would flag no matter how many bolts you found.

So you are saying Hot Tubs are hazardous on all decks without this? correct?? Also, why is the equation used OK?

Which question?

a typical inspection cannot predict all variables of an additional load source or outcome
http://www.wsbtv.com/news/news/local/deck-collapse-sends-7-hospital/nPFzC/

The challenge sated…

Well, we have an equation that says what the correct spacing should be. Is it correct?

Yes, it is correct.

Why is it correct?

Forget the “equation”, as the document states, it varies with “deck loads”.
A hot tub is one of the worst case deck loads.

You could even possibly have less bolts in the ledger if the deck had another properly built sub-deck built under the tub because now you would have an equivalent smaller deck.

What is your background and why are you reading more into this than needed? :slight_smile: