Raising Sections of Pole Barn Roofs
Reader LONNIE in COLORADO SPRINGS has some ideas about how to raise sections of his new post frame (pole barn) building roof.
For your reading pleasure, I will share:
“My question is concerning the assembly of my Hansen kit. I’ve read your article about using winch boxes to raise partially assembled roof sections and that was/is my plan for my roof assembly. I have purchased 4 small (2500 lb) wireless controlled electric winches that I intend to attach to the top of the 4 posts for a given bay. As the assembly manual says to double the interior trusses before setting them on the notched posts, I was planning to build and raise the 1st bay then skip the next, raise the 3rd and continue down the length of the building.
My question is if it would be acceptable to not double the trusses on the ground but assemble each bay section and attach the trusses together after the bay sections are raised? i.e. build the 1st bay with the single end truss and a single inner truss on the ground, raise the section and temporarily attach the end and single truss. Then build the 2nd bay, raise it then attach the 2 inner trusses once the adjacent bay sections are raised.
I know I’m not making my question very clear but basically I’m trying to figure out if I can build each roof section with only 1 truss on each end then attach the inner trusses together after the roof sections are raised. That way, I can build all the roof sections on the ground instead of just every other one?”
Mike the Pole Barn elaborates on winch boxes:
For those who are unfamiliar with winch boxes (aka truss jacks), here is the scoop (scroll down to the third question and answer): https://www.hansenpolebuildings.com/2013/09/hand-lift-jacks/
Using winch boxes is such an excellent way to raise post frame building roof systems. Hard for me to understand why more builders do not use them, other than perhaps not having been exposed to the concept.
I know exactly what you have in mind. I have a former builder friend in the Pacific Northwest who used to construct our buildings exactly this way. There is only one major challenge – the joist hangers should be attached to the doubled interior trusses with 10d common nails, which are three inches in length. You could use enough 1-1/2″ length nails or screws to keep the purlins attached to the single trusses, then replace them once the bay sections were up in the air, with the correct fastener.