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Collar + Rafter Ties Roof Framing - No Load Bearing walls needed, right? 3

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Grimloktt

Military
Apr 19, 2020
5
Hello. I searched for a forum where I could post this question. So, I hope I'm in the right spot...

From everything I know and read, this house's roof framing does not require any type of interior load bearing walls. Can anyone confirm that understanding?

The house's roof framing consists of collar and rafter ties with the rafter ties sitting directly on exterior walls and are also acting as the ceiling joists. I cannot find any information pointing to the need for an interior load bearing wall with this design. Picture attached. Thnx in advance!
 
 https://files.engineering.com/getfile.aspx?folder=980ea49d-32c4-4747-8795-98495d695655&file=Roof_Structure.jpg
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Absolutely BA. The framing of some of these older roof structures is pretty funky by modern standards, but they seem to work... for the most part.

We live in an older residence from ‘55 with a stick built roof of the similar construction. No worries so far...

Mike McCann, PE, SE (WA, HI)


 
Can this be done - double up the collar ties and install hangers to support the ceiling? The setback is adding weight to the rafter, thus a strength check is necessary.
 
retired13 said:
Can this be done - double up the collar ties and install hangers to support the ceiling? The setback is adding weight to the rafter, thus a strength check is necessary.

Seems to me that would be more costly than providing ceiling support from below. If Grimloktt can tolerate partial wall removal, leaving an opening of, say fifteen feet, the concern about the roof evaporates. It would not require the services of a local engineer. I think it is the best way to go.

BA
 
...and to follow up on BAretired's comments - the BIG challenge always with collar ties is that the nail connection to the rafter is always, always, very difficult to achieve...especially the higher the collar tie is relative to the height of the attic.

Doubling the collar ties makes the connection even more suspect as you have too many nails grabbing the same piece of rafter wood.
Adding hangers from these collar ties also adds to the total shear of the connection - hanging ceiling dead and live load.
Finally - the rafters...poor rafters....won't work I'd bet.

 
Yes, nailing is not desirable. How about connect the hanger directly to the existing collar tie using Simpson Truss Connector Plate, if the tie and rafter are strong enough?
 
These interior walls ARE bearing walls, as they support more than their own weight. I agree that 2 by 6's cannot span 25 or 26 feet without intermediate support. I also agree with just about all posts. In this case, there are several not so expensive fixes. Hire a Structural Engineer to give you one or more alternatives.
 

They are available in 26 foot lengths... just are VERY expensive.

I agree that connections are critical here to develop the tension in the 2X6's, but it can be done with metal straps.

An accurate structural roof framing plan would help to see the actual existing load paths and exactly how the system works....

Mike McCann, PE, SE (WA, HI)
 
I appreciate everyone's responses and the healthy discussion here. I remeasured and the span is ~21'-- still too long for 2*6s. I did speak to local engineer and reviewed the different options. I believe we'll be hanging a lvl above the joists strapped to the joists of course all the sitting on supporting posts.

This would reduce the span held by the 2*6 to ~10.5 feet.

Any thoughts why this wouldn't work?
 
No reason at all. That is why is I suggested it as the first response to your original post!

XR250
"Also can add a beam in the attic on top of the ceiling joists to support them from above. Would still need to bear the beam somewhere."
 
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