Hip roof support

[Dynocon]

Looking at a brick ranch built in the 70's, the roof is hip with a ridge board, house is L shape configuration.So 2 ridge boards and each board has a 2x4 a couple feet from the end, nailed to the side of the ridge board and toe nailed into the top of the wall or ceiling joist. These 2x4's have pushed the sheeting up an inch or so, not sure how many years it has been like this, but should these have been removed when the sheeting was installed? How much movement is normally realized during loading?

 

[msquared48]

No way to answer that without a whole lot more structural information about the building.

Mike McCann, PE, SE (WA)

 

[Dynocon]

Let me know what info you need.

 

[dik]

Do you have a roof plan and a section?

Dik

 

[KootK]

If the 2x4's are oriented vertically, they are probably creating the necessary heel height and transferring the hip rafter reaction to bearing. And, by the sound of it, the rafter to 2x4 connection may be giving way allowing the roof to settle around the 2x4. At least that's my best guess based on the information provided so far. I'd recommend posting a sketch of the framing plan in this area as well as a detail sketch of the particular condition that concerns you.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[HouseBoy]

The L shape description suggests that the ceiling joists and roof rafters are not all align in a favorable way (to provide tension anchorage of the rafter tails).
I suspect (as does KootK I think) that the ridge line (and resulting rafters) are dropping.
Often, the 2x4 props were used to provide temporary support (to align things) and in one sense maybe they could/should have been removed but usually they are simply left in place.
The "problem" that I usually find is that the remaining structural components are not truly capable of safely supporting the code required loading.
Roof plan and/or photos will be helpful.

 

[KootK]

as does KootK I think

Yessir.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[XR250]

I have never seen a 40 year old brick ranch with a hip roof that has not begin to sag. They require support at the hip/ridge and also usually at mid-span on the hip.
I rarely see problems with similar high-pitch hip roofs

 

[Dynocon]

I will take some photos and upload.

 

[Dynocon]

This standing a near the end of the ridge board looking toward the 2x4

 

[Dynocon]

Looking left.

 

[Dynocon]

Looking right.

 

[Dynocon]

Bottom of 2x4 on top of wall.

 

[Dynocon]

2x4 pushing up sheeting

 

[Dynocon]

Looking backwards

 

[Dynocon]

Looking back other side.

 

[Dynocon]

do these photos help?

 

[KootK]

They help me to realize that my initial comments were off target. From what I see, it looks as though the 2x4 may indeed have been installed as a temporary support that probably ought to have been subsequently removed.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[HouseBoy]

Perhaps it was intended to be temporary but it the roof is "sinking" so... the remaining roof framing is not performing suitably with or with out the extra prop in place.
"L" shaped plans with hip roofs that are stick framed without structural ridges are not likely to work.
When I come across them, I often find that "internal ridges" installed in the attic space can be an effective solution. Although, you want to install that framing in the morning!

 

[Dynocon]

Did these photos help?