ridge beam(s) support on VC

Started by MikeT, February 26, 2007, 03:40:09 PM

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MikeT

While I am not at that stage yet, I am trying to think ahead and understand the ramifications of each of my decisions.  

When I look at your sketches for VC as well as for the original victoria's cottage in the gallery, it looks like the main ridge beam is supported by a header at the top which also frames the window near the peak.  Then the load is transferred uninterrupted down to the foundation.  

Then when I look at the Kahn's version in the gallery, it appears that their window extends into the load line.  

So my question involves how inviolate the load path should be for the ridge beam?  I also noticed that in the gallery of the original VC that the header is supported by 2, 2x's (2x6's) rather than just one.  I assume that is pretty important, no.  For the Kahn's variation, would they have had to use a larger, built up header to carry the load down?

I am planning on keeping my load line just like in the plans, but I wanted to know about the advisability of changes and what that would imply.

Thanks,
Mike

jraabe

#1
When you are carrying a heavy point load such as the end of a beam, it should be supported by solid bearing to the foundation. If you want a window you would carry that point load with a heavy header to the double studs at each end of the header. These now split the load.

Unless you can check it with a load trace you should be conservative and don't go too wide on the window and use something heavy such as double 2x12's for a header. Also, when you do structural sheathing it helps transmit the load into the wall diaphragm.

Often times you can run the post straight down and then place standard windows and headers on either side.


MikeT

I think I will tinker with a field change and instead of having a 3050 window at the of the ridge, I will see how two smaller windows would look on either side of a support going straight to the foundation.  That will allow me to have a larger window below and not have to worry about interrupting the path.  But on the other side of the house, I will still go with a 3050 window and a supporting header that splits the load and then goes down to the foundation.

Do you think a field change like this needs to be taken to the county?  Or since this is actually "better" is it a non-issue?

glenn-k

#3
Many times on noncritical things I do it then if the problem arises I get it approved after the fact.  I be sure that it is something the engineer will accept and is done to code standards.  (Where I am concerned with the code). :)

John may have different comments on this - the above is just the way I do it which may not be right.  

jraabe

Things such as this are usually best worked out with the field inspector (framing inspection) rather than the plans reviewer at the office. They are often more practical and experienced at what works in the real world.


MikeT

With this beam design, supported by posts on the ends, does that make every wall a bearing wall and in engineering terms, which walls bear more, the ends with the beams or the sides with the rafters?

jraabe

The gable end walls will have these point loads that need to be carried to the foundation but the walls as a whole are not supporting as much of the floor and roof loads. The walls that carry the rafters are loaded more heavily than the gable end walls.