Bizzare structural arrangement in bowing roof – no rafter ties?
I encountered an odd situation in the roof of my detached garage. It’s a 1950s rafter system (2×4 rafters, 2×2 struts). There are joists which I thought were serving as rafter ties. However, the joists are each about 2″ offset from the connection between the top plate and the rafter, and from what I can tell, they service only to support the plywood ceiling underneath.
As far as I can tell, the rafters are nailed to the ridge (sistered 1x4s) and to the top plate (2×4), and I presume use nails to resist the resist the lateral compressive load which would otherwise cause them to blow outward. From what I’m reading online, it’s highly unusual for a rafter system not to have a rafter or collar tie.
Unsurprisingly, the rafters on both sides are sagging and I’d like to support them at mid-span, and rehabilitate where needed. Suggestions?
I’d originally drawn plans to fix the situation (photo 4) assuming that the joists were serving as rafter ties. This no longer appears to be the case, so my plans are out the window.
If it makes a difference, I’m in a climate with snow and moderate winds, but not hurricanes. I was planning to install solar panels on the roof, which kicked off my dive into bringing the roof up to snuff.
Replies
Not trying to sound flippant or rude, but what you need there is a dumpster and a set of trusses.
Thanks for the laugh. To be fair, the timbers are 70 years old and aside from the sag, appear sturdy. These are old grown fir boards.
I'm envisioning a 10-15 service life for the structure, so would like to invest a few hundred dollars of wood and sweat equity in order to maintain its operability.
Not what you would do today. Dumpster would be the cleanest idea, but likely not in budget.
Looks more like a ridge beam, with the supports a bit on the undersized end of things. Those vertical boards really 2x2?
You could start with where your solar panels would mount and go from there.
Where would your solar installation mount?
I would hesitate to jack anything, but look to preserve the roof where it is now.