Building Homes or Extensions/4 by 6 limits

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Expert: - 5/3/2009


Question
I am tearing out a wall and wonder what span a 4 by 6 sitting on 4 by 4's can span safely.  Although this is not a support wall, there is 2 by 4 on top of the single 2 by 4 ceiling plate with 2 by 4 going up to the roof line.  Sorry so confusing!  It's is a 14 foot opening

Answer

typical hand framed ra
Hi Matthew, a 4x6 with no bearing weight can probably span 10-12 feet before it begins to sag over time.  It sounds like you are describing a king post truss of some sort.  Let me send you a drawing and see if this is what you are talking about.  If it is a king post then the wall is bearing some of the weight of the roof.  This post may be supporting your ridge beam.  If the other rafters in the roof system don't have collar ties then this end king post will be holding up a lot of the roof weight and a 4x6 spanning 14 feet will be inadequate. Without a fully supported ridge beam and no collar ties the rafters will have a tendency to push the walls out and the peak sinks from its own weight.  If the 4x6 is holding up the roof load the span shouldn't exceed probably 8 feet.  Look at my drawing and respond back to me for further discussion.  Sincerely bruce e johnson..bejohnsonconsulting.com

Bruce E. Johnson

Expertise

I can answer any construction related question in regards to carpentry, concrete, drywall, masonry, structural elements of any type of building, residential or commercial. Interior or exterior.

Experience

Custom Commercial and residential buildings. Churches, theaters, schools and auditoriums. Most recently I am working with the Catholic Church on several design build committees. I have a website related to scheduling and project supervision. Although my expertise is more related to multimillion dollar commercial, educational and theatrical projects my generous credentials in residential and remodelling construction make me a viable source of information regarding all forms of building questions.

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