Rafters separating from ridge board

[jmichalski]

Cape cod style home, concrete slab foundation. No exterior cracks on walls or ground. No evidence on interior of cracking drywall, stick ing doors, windows, etc (many nail pops in old, original drywall though). The rafters on the rear side of a steeply pitched roof were separating from the ridge board.

The top portion of the rater was still in contact, but by the bottom of the edge where the rafter abuts the ridge board, a full one inch gap was present. condition was only present on the rear side, left 9-10 rafters counting for the left exterior wall (most significant degree of separation) to the center.

Of course, no collar ties are present (recomendation made along with referral for evaluation and correction by a roofer).

The questions are: what is the cause of this and what is the appropraite repair (for my own understanding).

I normally would have thought that sinking, settling or other structural issue would be present, but I could not find anything....

Thanks for any help.

[Gerry Beaumont]

hi to all,

Joe this is commonly called "swayback" or "saddleback", basically the ridge beam has settled and has pulled down the top of the rafter to ridge connection opening up a gap at the bottom. Many things could have caused it so you did the right thing by defering it.

Regards

Gerry

[Gerry Beaumont]

BTW,

here is a frame from Inspection Depots Illustrated home guide that shows it.

Click here for images

Regards

Gerry

[Marcel R. Cyr]

Joseph;

It was a good move to note it on your report, but I don't think that a typical roofing Contractor cannot contribute to much to this problem.

Did you notice any sag in the ridge from the exterior or bulging of the exterior walls?

The reason I ask, is the photo appears to show some of the rafters still well fitted to the ridge board. This would indicate to me that there is a possibility some of the rafters to have been cut wrong when originnally installed.

Why is the rafter in the picture so much whiter than the other, or is this just the flash?

No collar ties in this type of framing definitely calling for trouble.

Weird as to why one whole side of the rafter on the spotlight has no nails visible.

Just my thoughts.

Marcel
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[Larry D. Kage]

Originally Posted by jmichalski

I normally would have thought that sinking, settling or other structural issue would be present, but I could not find anything....

Thanks for any help.

When I have seen this the center of the exterior wall running parallel to the ridge is usually visibly bowed out some. I say usually because sometimes it is not evident because there may have been a residing and soffit/fascia job where an attempt was made to straighten the wall plane during that process.

The attic can tell a good story. Good job catching it.

[Marcel R. Cyr]

To use and example, I would like to point out that if a rafter were cut for a 6/12 pitch which is 26.57 degrees at a 16' run, the rise would be 8'-0".

Change that plumb cut by 1 degree and the rise would change by approximately 4".
No siding remodel would hide this.

Marcel
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[jmichalski]

Thanks, guys.

No bowing was observed on the rear wall (parallel to the ridge board on the side of the pictured rafters). It is sided, so I may have missed it, but it is a single story wall with several (5, I think) windows and a rear door penetration, so there is not actually much solid wall to bow. No doors or windows stick.

The side wall had some cracks in the stucco work near where I suspect the framing for the first floor meets the second (floor joists). If the rafters continue down to this point (I believe they do) at the rear, could it be that this movement of the roof casue some pressure on teh right wall of the home which would be evident as stress cracks from above the window frames to the frames? (No bowing of this wall was observed either and I checked it with a carpenters level for plumb because I saw the cracks).

Last question: What is the repair for this? (for my use - not to relate to the client) Can it be shimmed or sistered to become structurally ok again?

thanks!

[jmichalski]

Also, I think the color differentiation is a result of the flash and flashlight present. The rafters all appeared to be the same in color when I looked with the naked eye.

Also, no dip was noted in the ridge - it looked pretty straight.

I can see how a slight, imperceptable shift would send it all out of alignment. Is it possible that this happened on one side of the home? And if so, why would it only be evident on the rear, right rafters and not the front?

[Larry D. Kage]

Originally Posted by jmichalski

Last question: What is the repair for this? (for my use - not to relate to the client) Can it be shimmed or sistered to become structurally ok again?

Joe, I don't know the repair because I don't know the problem specifically.

On one inspection where the ridge sagged and the walls appeared straight I was able to see the connection between the rafter tails and the ceiling joists. It was opened up with the one nail used bent over from the sheer force of the rafter moving out past where it originally sat on the wall nailed to the ceiling joist.

After some talk with my client and the homeowner we found out that the siding guy cut all the rafter tails off to straighten them out before he applied the new fascia and soffit and siding.

I deferred it but I believe making a better rafter/ceiling joist wall connection would have helped.