3.5″ nails into 3″ of wood at ceiling joist to rafter connection
SoreThumbBrad
| Posted in Code Questions on
Hi and thanks for any help ahead of time.
I’m designing a gable roof, with a non structural ridge board, per the prescriptive path in the building code.
The building code requires using 16d nails (which are 3.5 inches long) to connect ceiling joists to rafters.
Since both joist and rafter are nominal 2x lumber we only have 3″ of actual wood to join.
Does it make sense to use a 3.5″ nail with 3″ of wood? Or did I miss something?
For reference I am reading
2020 Residential Code of New York State
Table R802.5.2 Rafter/Ceiling Joist Heel Joint Connection
Required number of 16d common nails per heel joint splice
Thank you,
Brad
Replies
In almost 50 years of building I can't ever remember deliberately using a common nail. When I started standard practice was cc sinkers (cc = cement coated). Vinyl coated sinkers soon became standard. When I started using gun nails a 16d gun nail was actually 3 1/4" not 3 1/2". The code was written way back when and the length was called out to specify overall size of the nail. Thus 3 1/2" actually meant 16d. There are 3 1/2" gun nails now but 3 1/4 are still more common. A 3" nail is a 10d and these weren't suitable for rafter to joist connections. So just use a 16d gun nail.
Hanger nails come in penny designations but this refers to the diameter not the length. The size is marked on the heads for inspection. There are other odd nails. For example 10d shorts are a gun nail used for sheathing where you need a larger diameter but not length.
Thanks very much for your help!
Brad
I'd ask your inspector, then you don't have to worry about the hassle of not doing it right.
Thanks for the idea! I actually did ask. They seemed entirely ambivalent about it.
I may be to late with this but the simple thing is that you put the 3-1/4” nails in at a slight angle so they don’t poke out the other side. You get the full length and diameter of the 16D (my gun nails are 3-1/4 x 0.131d) without creating a hazard on the other side to tear some skin.