I need some framing engineering answers! Hopefully…
I’m using this detail (H5) from Weyerhaeuser’s TrusJoist to install conditioned roof attics framed with 14” I-joist and a double 16” LVL beams. I plan to fill the cavities with 14″ R50 DP cellulose with a vapor diffusion port. House is design to 140 MPH windspeed.
The framer asked me if the roof sheathing goes before the LSTA30 strap or if the roof sheathing goes after the strap? If the later, how to “nail” the roof sheathing through the strap? Does a framing gun has enough power to go through the straps? What happens if we “hit” a strap nail?
I talked to the Engineers at Weyerhaeuser, Simpson and the project’s SE, and ALL OF THEM said that no one had ever asked that question, and they all said “talk to the other Engineer” … So, any ideas?
I think that installing the roof sheathing first, and then the metal strap is better. What say you? Thanks.
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Replies
The strap goes on first . It is 18 inches long so after the 3 1/2" lvl you have 7 1/4" on either side of peak. It will be fine
Armando,
I've had no problem penetrating those straps with a nailer. You may get the odd one that hits a nail head. The new one usually pancakes and jams your gun. Pop the nose and you are back in business.
I have asked structural engineers and they have said that it doesn't matter, which was good in at least one case because I didn't think of it until after the sheathing went on. I prefer to hide the strap under the sheathing but in some ways it probably holds better if the nails are going through the sheathing.
Thank you all for your input. I can't imagine how Weyerhaeuser and Simpson recommend the installation of their products without testing it, especially since all roofs and most walls are sheathed with plywood or OSB.
Anyways, we decided to install the sheathing first, and the project SE tends to agree also. 🤞