Inspecting a detached garage built approximately in 1940 that has the interior remodeled to on the 1st floor and in the attic. Inspecting the attic I found the rafter ties that do not sit on the wall and fall at the upper limit of the bottom 1/3 and are made of overlapping .75" x 8" common boards of varying lengths nailed together to obtain the required span. Additionally, the rafter beams are reinforced by steel twine to a 4x4 post which appears done to avoid sagging in the drywall in the finished areas. Consultation was needed to install solar panels. My recommendation is for a structural engineer to assess. Any comments/thoughts?
I would if it were my client based on what you described and your comfort level. Load calculations may come into play.
“rafter beams are reinforced by steel twine to a 4x4 post” that language alone leaves me totally lost. Those are not construction terms.
Rafter ties don’t have to “sit on the wall” but they need to be low down in the roof.
What are you actually asking?
I think you are looking at a poor man’s version of a strong back?
Well yes, it looked kinda like that. LOL… I don’t know Scott. I’m not even going to guess at the "steel twine to a 4x4 post”!
Never use the term “steel twine” in a report.
Thanks Joe. What terminology phrase would you recommend instead of the “metal twine”?…it’s the first time I’ve come across that.
Keep the terms simple in your report. “Improper reinforcing/construction of attic structure”. I agree that a structural engineer would be needed to assess the structure especially if solar panels are going to be installed.
Kenton. Thanks for the response. These are rafter ties raised above the lower 1/3 portion of the roof system. The rafters ties measured .75”x6-8” nominal lumber and each did not span independently across to each rafter so 2 boards were used and nailed together to make the distance. I never seen lumber that thin used as rafter ties and questioned their ability for them to resist the tension forces required. I suspect the 4x4 column was installed to add stability to the rafter ties and minimize any deflection when the remodeling took place though I could be wrong. I don’t think it was a stongback.
This was in a 1940 detached garage where the 2nd floor was remodeled to conditioned space. The roof system has stood the “test of time” but the clients wanted to install solar panels which would increase the load.
I appreciate any feedback and comments.
And Happy 4th of July to everyone!
I’m with @jdepiero
Keep it simple.
I observed unconventional roof framing techniques and materials. The roof/ceiling has apparently been modified over the years. I have concerns the current structure may be inadequate for additional weight loads. Recommend further evaluation by a qualified structural engineer prior to the installation of solar panels.
The ceiling joists (serve as rafter ties) appear to be over spanned and lack midspan support.
Thanks for the feedback.
Thanks everyone for the feedback and article!
Most rafter ties are 2x4, 2x6 of whatever the ceiling joists need to be according to the span. If they are ¾" as in 1x4 or 1x6, I don[t know what to say. That would be an engineers call.
Ooops, I see now. Like Scott said, it’s a poor version of a strongback installed to help keep the ceiling joists from sagging. Sorry for the late reply.