Replies

1. 
   Piffin | Mar 16, 2006 11:02pm | #1

   WE don't generally need to make it too difficult with formulas unless you have an especially unique situation.

   But

   It does take into account how much load you are placing on the header and how wide the window is.
   The load from above is what it bears. So whether you are in a high snow load area, whether you have a roof only loading it or whether there is also a second floor landing on that wall make a difference.

   So maybe you can answer those questions first?

   Help out too by answering another question - Can you define a jack as used in wall framing?

    

    

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2. 
   Thaumaturge | Mar 17, 2006 12:25am | #2

   While I am not an engineer and have installed lots of thick headers over windows, there is an emerging trend to dramatically reduce or omit the header altogether if the window is sufficiently narrow or is located in a gable end wall.

   FHB #174 had an article on smarter framing that made a lot of sense to me on this topic.

   The formulas you need can be found in many places on the web and in print.  Do a search on "header sizing" here as well for much information.

   This question may also qualify as one that implies if you have to ask, you should not be doing this without help from a pro like Piffin. :-)

   
   

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   Edited 3/16/2006 5:27 pm ET by Thaumaturge

3. 
   JohnSprung | Mar 17, 2006 01:58am | #3

   Check with your local building and safety department.  They may have a xerox handout of generic details for single story residential stuff.  Ours does, and it has a table for headers of #1 DF for tributary loads spanning up to 20 ft.  and headers spanning up to 12 ft.  Rule of thumb, four by "n" in inches is good up to a span of "n" feet.  4x4 for 4 ft, up to 4x12 for 12 ft.  But don't go by that.  Go by what your AHJ gives you. 

    

    

   -- J.S.