Exterior use truss uplift screw Values?

[engreg]

I am hoping to use some truss screws like SDWC’s. I need ones are for exterior use though, and It doesn’t look like I can use SDWC or its values exposed to weather. Anyoneknow of any exterior use truss uplift screw and have access to its values. Owner wants screws for aesthetics on an outside porch, so clips wont work.

 

[engreg]

Any info on values for toe screwing SDWS Exterior Timber screws could also help.

 

[XR250]

I thought the black SDWC could be used outside

 

[engreg]

"SDWC15450 (this is the black one) is recognized for use in chemically-treated wood as described in
the evaluation report." - This is what the simpson book says - It says chemically treated not exterior use. Where most screws in the simpson book explicitly say exterior. How do you read that?

 

[XR250]

I don't know. Most chemically treated wood is exterior use.
Why can't they make these for exterior use like their other screw?. They are handy AF in many situations.

 

[met33]

I've never used them, but the FrameFAST screw from FastenMaster is marketed for exterior use. I think they recommend against using them in areas exposed to saltwater/spray, though.

FrameFAST Structural Framing System

"Approved for use in exterior applications including treated wood (ACQ-D)."

 

[RWW0002]

Simpson's literature specifically addresses wet service factor for several other timber screws. I would think that at the very least a Cm of 0.7 would be applicable (per NDS) for screws in withdrawal. Simpson is usually very responsive to questions such as these and may share some practical advice and/or testing data.

As an aside, something about relying on screw withdrawal as primary (uplift) load path in members that may shrink and swell significantly many times over their service life does not sit well with me.. That being said, if Simpson has tested it I might be able to get more comfortable with it depending on the actual application.

Also, worth pulling the ICC report and seeing if wet service is mentioned in there.