Going to be extending my roof ( by 8') over the front porch in a few months. When I attach the joist/rafter hangers to the ledger board it calls for 3" 10d sinkers nails, would 3" deck screws have the same integrity as the nails ? Just stick with nails ? -Thanks

screw would better as long as they are deck screw , it really comes down to what you your anchoring new roof to

Ledger board attached to house with 2x6 rafters and 1x4 perilings for steel roof.

screws do not have the shear strength of nails. Since these will be loaded in shear, use nails.

There are special screws made for joist hangers. I think they are call strong-drive. I have used them for deck joists but you could check to see if they are code for roof joists.

It's about the shear strength for joist hanger nails. Those short stubby nails made for joist hangers can withstand a tremendous amount of shear before they break. Most screws do not have that level of shear, not even close.

Jim

That is correct.

Make sure you use the correct nails described by Jabne.

whichever you chose, make sure you use the right stuff.

if you want screws, the only screws I would recommend are the Simpson Strong Drive SD Connector screws as they are specifically designed for these applications and depending on the size used, have a greater shear strength than 10d or 16d nails.

joist/rafter hangers are engineered to be USED with what it calls for. If you want to use one that calls for screws - good luck finding them - most I have read about call for nails for the designed sheer strength. I would not want to cut any project short to save a few bucks knowing it is not built to specs as designed

Glad I found this thread... Im planning a 16 x 52 pole barn addition.

There are special screws made for using hangers otherwise nails are the proper fastener, and the hanger will have a specific nail size too. Regular screws don't have the shear strength. They're more brittle to begin with, and a nail and a screw with the same outside diameter won't have the same strength, because the screws threads don't provide as much strength as the solid nail.


That being said, when I rebuilt my deck I used regular screws from the hardware store labeled "structural screws" because it's easier and I didn't know any better at the time. Your mileage may vary.

^^^^^^^^^^^^^^^^^^ Also, most joist hanger nails have a larger diameter than similar sized screws AND they are electro-galvanized where screws are not.

I should add - every hanger will also have an engineered load design based on the number of fasteners used. You can not just put a single nail into one and assume its good. You need to follow again what it calls for. It might be 3-4 nails a side to displace the weight where a single nail could possibly hold it up - it will not meet specs.

If your joists are sitting on a foundation I dont see shear strength being a factor at all.

I always use the Simpson screws.

He's asking about a rafter application . Not floor joists

Rafters are under compression. The weight of the roof itself should hold them in place.

I'd use what the engineer recommends. If you are concerned with nails pulling out, perhaps you could use ringshanks. If you are concerned with the nails rusting out, perhaps you could use galvanized nails. Talk to your engineer and go with their recommendation.

The hangers will only be as strong as the ledger board and how it is attached also. Or am I missing something?