gable roof with with vaulted cross gables and structural valleys

[lubos1984]

Hi Guys,

wanted to run something by you. I'm working on a garage where the client wants to vaulted the attic space for storage.
He doesn't want any intermediate posts to maximize storage space.

The attic floor is the garage ceiling with joists bracing the exterior walls. I have attached my understanding of how the roof would act under load. My understanding is:
- the longitudinal ridge acts as a ridge board and not a ridge beam
- the valleys act as structural beams supporting the rafters. (shown in green)
- the valley will need to connect to a ridge beam (green). The only load the ridge beam is taking is from the valleys ?

Attached is a pdf of the sketch.
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1720005536/tips/Picture_1_002_anystw.pdf[/url]
Thank you as always for your feedback.

 

[XR250]

I usually make all ridges and valleys structural in these cases.

 

[lubos1984]

do you think the ridge board would act structurally here ? Assuming the valleys can take the thrust of the rafters I was thinking the ridge board would act any different then in a typical gable roof.

 

[XR250]

In reality, yes. Proving it is another story.
I have seen plenty of these roofs without structural anything perform fine for decades.