We are considering building a SIPs home.  I have sent out my plans to three companies.  Two companies put support in their walls for my ridge beam.  One company tells me that this is not necessary.  This company says that the panel (polyurethane with osb on each side) will support the ridge beam.  This is how they build and their engineers support this.  I'm sure they all have their reasons, but my concern is whether the ridge can be supported on just the wall without any other support.  Does anyone have any experience with this?  Does a 4.5" panel have that kind of strength? I don't want my walls to sag in a few years.

ppreston;

Yes, in most cases the skin has sufficient shear strength to carry the load. We do it all the time with our 26ga. steel skin SIPs , supporting a steel box beam with an 18ga. steel "U" bracket.
Have not seen one fail or sag yet. Our engineering also supports it as well.

I don't know the size of your building or the span of your beam. But in most cases we would put some type of vertical supports under such a point load. Some companies call for them, others don't. I tend to error on the side of caution.

I would tend to side with Wes. We typically use either gang studs or stud-foam-stud support at the ridge beam and create a beam pocket with the panels for it to sit in. This is especially useful if your beam is extending past the walls as roof/overhang support. It also makes for easy install for your roof panels to line up with the pitch of your wallls.

Oh ye of little faith

Or a lack of stupidity. How many building inspectors/departments, are going to allow a point load to be supported by a couple of hunks of tin glued to foam?

Faith is one thing, common sense is another.

A lack of stupidity ? Would be not stupid? golly gee, I guess about 150 building departments and inspectors scattered thru out Florida, Louisiana and Texas are just not as smart as you OR maybe you are an expert is steel SIP technology?
Several Steel SIP homes have hurricane tested up to cat 5 with same connections and suffered no structural damage

Maybe we can still teach you OSB guys something yet? You just have a hard time accepting that our steel panels are better.

Monocoque Construction ................... Link

One of Bill Chaleff's articles discusses this. 

http://www.greenbuildingtalk.com/buildcentral/sip/m0105.aspx

Good luck,
Larry

I read that link and lso feel that there is a lot of overengineering go into SIP homes in regard to timberframing.  I remember when I first looked into using SIP's (5 years ago) There were a lot of pictures showing the panels connected to one another at the ridge with no timber beam supports at all. 

I think some if not most engineers (that are unfamiliar with SIP panel strength and usage) side on the exstreme side of caution and overengineer the roof structure as if it were a bridge supporting a train.   At least thats what they did on my house.

I have done it both ways here in Southern california. It really depends on the area. Most but not all of the area here is siezmic zone 4. Some of the panel manufacturers also have different point load numbers. I have built with R-Control and Premier and Premier has higher testing#s so the engineer will call out less additional shear walls and pockets for posts etc. in most cases a double top plate will carry most beams...

I am currently installing Fischer Sips and have a 30 foot 18 inch triple LVL free spanning 26 feet.  Fischer did call for a quadruple 2X4 sandwich in the gable sips and first floor sip seams that ran below the point load.  FYI only.

Bill