Any roof framing experts here?

[G50]

Do those circled 2x4s do anything?
Looking at the extreme angles they are at, it doesn’t seem like they could be holding up the roof. Also, they’re barely nailed in.
I guess maybe they prevent the top beam from moving laterally?

[herr_oberst]

I'm not a roofing expert. Just spitballing a thought or two here.

It looks like a homeowner or a "contractor" "fixed" a sagging roof.

Do you get a lot of snow? How many layers of shingles are on your roof?

[917_Langheck]

Originally Posted by herr_oberst

I'm not a roofing expert. Just spitballing a thought or two here.

It looks like a homeowner or a "contractor" "fixed" a sagging roof.

Do you get a lot of snow? How many layers of shingles are on your roof?

Yup, looks like secondary construction, sistering in a ridge beam (as best as I can tell from that pic) and shunting the load, hopefully, to a load-bearing wall. Roof slope looks pretty shallow, like 3 in 12. Snow load would be an issue, but local regs wouldn't probably not permit such a shallow pitch.

[A930Rocket]

I’m no engineer, but it looks like a stiff back was added to help support the roof. Seeing a small portion of the roof system, all I see is rafters with collar ties. That would not fly, especially if you get snow.

You might want to get a structural engineer involved

[Dantilla]

Originally Posted by G50

I guess maybe they prevent the top beam from moving laterally

This ^
Not as important now that the original skip sheeting has been overlaid with OSB, offering sheer strength.
Definitely not up to building codes, but not uncommon.

[john70t]

Are those 2x6 rafters which are 24" on center?

Having a low pitch, heavy snow load weight could suddenly collapse the roof in the middle, or slowly 'swayback' the ridge beam which would push the center of the walls out.

The triangle structure takes a bit of that load and drops it onto interior load-bearing walls. Hopefully that wall is over an I-beam in the basement holding up the first floor. You can measure from the edges of the perimeter and follow it all the way down.

It's a bit of a (insufficient and on an angle) hack but the right idea.
Snow would make all the difference if more is needed.

[G50]

This is an all original California coastal mid 60s upper end tract house. So no snow load requirements.
I of course don’t know for sure, but I’m pretty certain this is all original construction, nothing has been added. The wood, nails, etc all looks the same age, and the house hasn’t been modified of added to.
I recall reading somewhere a long time ago, in connection with a different house, that those 45 degree circled 2x4s were really just to stabilize for the construction phase, as Dantilla suggests. But my memory is fuzzy on that.

[David]

If you want to remove them, you can measure the horizontal brace's (purlin) vertical distance to a ceiling joist. Then remove the diagonal brace and check how much the purlin sagged. If 1/16" or less, not much load on it. If more, you should replace the brace where it was or with another brace that provides similar support. I have removed them but I replace with some other brace that doesn't interfere with what I'm trying to do.

[cabmandone]

Looks like they were trying to support the bottom chord as well as support the center and prevent sag. I'm guessing the board in the first pic runs up to the ridge and prevents lateral movement. The second pic, those angled boards offer little in the way of preventing lateral movement or sag from the support beam in my opinion. There's no strength in the board the way they're installed.

[Magyar Kiwi]

The second photo, (with the two red circles) fails to show what the bottom ends of the circled parts are attached to ?
Are they attached to the top of an internal wall ?
This information would be useful.
Cheers

[917_Langheck]

Reading the pics on the phone is always dangerous. Is yours a gambrel roof?

[afterburn 549]

They point loaded , not a good thing, unless the is a load-bearing wall under these.