Roof Framing Layout 5

[STrctPono]

I was sent a preliminary house roof framing plan by the drafter/designer who is playing architect and it gave me some pause. Can you guys help me wrap my head around this framing plan and the concerns that I have. It seems as if he drew everything as it was convenient to the exterior perimeter layout but didn't really think about the areas that need interior supports. You can see the outline of the interior walls (dashed) and they don't line up with the locations that need posts.

1. I circled some areas in green that are unsupported. Can you confirm that these areas will either need to be supported with a post to the floor below? Any other areas I'm missing?
2. Can you frame a girder truss into a hip/valley truss? Is there any reason why this would not be allowed?
3. Any other suggestions or problems you see with what is shown right now would be greatly appreciated.
4. The very little guidance I was ever given in regards to designing homes was to callout a minimum 2x6 pre-engineered roof truss at 24" o.c. Not sure if this is even correct and seems more like a bare minimum requirement if anything. What's the standard approach to calling out pre-engineered roof trusses on structural roof framing plans? This particular house is using concrete monier roof tiles. Would that change anything other than how I account for the loads to all the supporting elements? This is in a hurricane prone region.

This is still very preliminary and can be changed as needed but I was hoping for some input from you guys who do this a lot. I do not design houses very often, and my experience with rooflines that are anything other than a rectangular box or stick framed with ridgebeams and rafters is nonexistent. I don't really have anyone that I work with that I can turn to for help.

 

[STrctPono]

KootK, as usual... your expertise and commitment to providing thorough and detailed advice is spot on! The sketch you provided makes perfect sense.

What? With posts mixed in for support of roof framing though, right? Pic.

I'm afraid not. Not a post to be found. The type of construction is called single wall construction and the majority of these houses are built out of redwood. The technique fell out of favor sometime in the late 70's early 80's when it became mandatory to build stud walls. They are still super prevalent in the state though. Heck, my house is one. They're total pieces of crap but are easy to remodel due to their simplicity.

Here's what a typical one would look like....

 

[Lomarandil]

3/4" T&G... wow... just another humbling moment of "I don't understand why that works"...

KootK-- thanks for the sketches. Top notch -- learning a lot here.

----
just call me Lo.

 

[phamENG]

Talk about depending on a roof diaphragm to prevent wall spread (ceiling - where occurs). Wow. I guess the wall girt and it's connections are critical. Sort of acts like a tension ring to prevent wall buckling? I'm pretty ignorant of the weather in Hawaii. Are cyclones pretty rare? If so, I could see these working. I imagine they'd flop all over the place in an earthquake and spring back up when it's done.

KootK - thanks for posting all this invaluable prefab truss info.

 

[STrctPono]

Talk about depending on a roof diaphragm to prevent wall spread (ceiling - where occurs).

Most of these homes were built before plywood was readily available so most roofs like mine are just also tongue and groove boards. The majority of these homes use either site built roof trusses or rafters and ridgebeam. I can't recall ever seeing one with a ridgeboard.

Are cyclones pretty rare?

We're in a hurricane prone region and get a few close pass byes each summer but it's been awhile since any full on landfall. Obviously nothing compared to Florida.

 

[BUGGAR]

I think KootK is using what is called California Roof Framing.

 

[KootK]

Technically it's a Midwest hip set although the terminology seems to be in a state of perpetual drift. Gotta give the flat-landers their due: They came up with the version that seems to have become dominant.