Why you never want to support a non-structural ridge beam (photo)

Note the next rafter to the left is interrupted by the skylight.
1943 building, and the skylight seems original.
Roof is architectural shingle maybe a decade old.

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It’s not about supporting a non structural ridge, it’s more about not having a structural ridge beam.
When roof slope is less than 4:12 the ridge acts like a beam and needs proper supports.

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Sure, you could read it that way.

Or try this one “if you have an older roof, don’t forklift load shingles onto one section of the roof. Carry the shingle bundles up only as needed”.

Or “if you see something say something - especially if you’re laying shingles and one section looks like a dinosaur’s back”.

Or “older structures may not meet current codes and building practices. Don’t shingle multiple layers on old roofs out of weight concerns”.

(See Chapter 8 of the International Residential Code (IRC) for a ‘compression roof’, related to new construction). No such requirement exists for retrofitting existing construction.

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I’m not sure if I understand you correctly. Please see section R802.4.4 of IRC or 2308.7 of IBC.

I’m not sure I understand.
I’m not trying to build a new house.
I’m reporting on how someone tried to shore up damage to an existing older roof, thus creating additional damage. The roof predates the IRC and IBC by more than half a century.


Looks like we may have a little issue over here as well.



So you think this is a design failure?

Yes, that is how I would describe the condition on the picture.

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That beam/board is cracked and is now displaced.
I would refer a general contractor for repairs.

How does the 1943 construction age affect your thinking on that, as a design failure?

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It doesn’t matter then the structure was built, when I see a problem, a material defect, or unsafe condition I analyze it based on the current requirements. As simple as that.

Maybe someone jacked up the main carrying beam, pushing the house’s center up, crushing the ridge board? Or perhaps the foundation settled, and the carrying beam footings did not settle, pushing up on the ridge board crushing it? Oh, by the way, in the Northeast, with conventual roof framing, we add posts under the ridge down to a bearing wall to help with snow load and have never seen one crushed.


This vison flies in the face of everything a home inspection is.


My advice is to reconsider that approach, especially in a home inspection report. For example, you can’t compare a modern roof rafter sized from a current code span table, to a rafter harvested and installed in 1930 without visually grading the wood and performing several calculation steps. You might able to speculate that a roof or floor was overloaded at some point in the past, but that is a far cry from making an outright claim that a design failure is at play without any proof.

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I think you are close. And if you look at the rafters and sheathing boards, they all have straight pit saw marks, with no signs of mill planing, while that 2x4 prop is obviously modern lumber.

My money is on someone tried to prop up a sagging roof, and years later the ridge board gave way under the new load path.

I agree here.
As inspectors we risk either being ignored, or sending owners on wild goose chases of fixing things that don’t need fixing. And, annoying the non-greedy professionals who get called out on the referrals.

For older buildings there’s an existence proof: if it’s been there X years, is there any evidence of a developing problem? Is it a home component that wears out?

In this case of this particular roof, on seeing the slope I immediately looked for signs of wall spreading. I saw no reason for concern. Combined with a context of an area with a recorded historic snowfall level of less than 1cm and a grand total of zero hurricanes, I see no reason to even raise the issue, and certainly not to refer to a SE or PE (beyond here on this forum, thanks Darren).

I feel my “A” from CYA is well covered in that this building is typical for the era, and the area, as well.

I am not saying everything is hunky dory with that roof, for the record. Something is obviously wrong with it, or the ridge board wouldn’t have shattered. I would have called that issue out in a heart beat.

You were just going after electromagnetic fields and now see no issue here? C’mon man… lol

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I am still wanting to follow Lukasz line of thinking. Please all, forget code for a moment.

Are 4:12 or less roofs likely to have problems if they do not have a ridge beam (vs the subject ridge board)?

Good question, I guess nobody has an answer?

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