Hoasote Firestall Roof Deck

[BJenkinsJEI]

Has anyone used this product as a structural diaphragm? The data available seems to be limited to two test results and does not contain the typical span/shear charts versus connection schedules that I am accustom to seeing. The architect is proposing to use this deck as a single element diaphragm, as opposed to using a structural steel deck under the nail-able deck. I'm being asked to render an opinion. Any thoughts/comments are greatly appreciated!

 

[MiketheEngineer]

What does the mfg say??

 

[BJenkinsJEI]

The manufacturer (supplier) is vague at best. They supplied two test results as proof of diaphragm capacity - no load tables, no deflection coefficients, and no connection details, (other than the test setup). Further, their literature refers to expansion joints in the system for lengths > 150 feet as well as "floating" the connections at shear walls.

The product may be acceptable for low shear values. The project in question is a 30,000 SF facility and I anticipate significant diaphragm shears.

 

[jdgengineer]

Do they have an approved ICC report? If not, and it doesn't sound like they do, I personally wouldn't use it.

 

[BJenkinsJEI]

I agree....they indicated that they did not have ICC reports.
Thanks!

 

[Ron]

Homasote is a weak material. I wouldn't use it in a diaphragm application. It is subject to localized crushing at its edges and at fasteners...moreso than gypsum board. Max. span is 4'. It is also limited to a min. 2/12 slope...so not good for a "flat roof" diaphragm.

 

[BJenkinsJEI]

Thanks for all the comments! We'll be heading in a different direction!

 

[MiketheEngineer]

Find something else.....

If mfg can't back their product - whey do we (including architects)even consider using them??

I suspect price

 

[Ron]

...or ignorance.

 

[shobroco]

I thought homasote was only used for display materials & temporary assemblies any more (at least for the past 25 years?). I figure if you can put a thumbtack in it, you don't really want to use it as part of your structure. Acually I must admit I've only ever even seen it specified by architects from western NY & I don't know a supplier in southern ON where I am.

 

[Ron]

shobroco....it was commonly used as a soffit board in the 70's. That particular variety of it had a bit of a hard surface.

 

[shobroco]

Ron: I don't know the material & always thought that maybe it's like what we know as tentest, which is available in a few variations, none of which I'd get too excited about. One version had a prefinished surface used for ceilings, bulletin boards, and cheap soffits.

 

[Ron]

shobroco...sounds similar...basic crap!