You are here:

Building Homes or Extensions/Load bearing wall beam requirement

Advertisement

Expert: - 2/3/2009


Question

rear view
I have a 2 story home that I want to put an addition on the rear lower level. This addition is on the outside corner of the home on a rear load bearing wall. The second floor is smaller than the first floor so the exterior wall bears more weight toward the inside than it does toward the far corner. I want to expand  outward and remove a section of this load bearing wall. If you look at the picture I have attached you will see an arbor in front of a rear door and that the rear door is directly under the "corner" of the second floor. I want to remove the rear wall from approximately the left side of the door all the way over to the corner on the right. I intend to support the corner with a post and span the approximately 8 feet from the post back toward the left side of the door with a beam tied to the end of the ceiling/floor joists so it will be hidden in the ceiling when finished. I will do the same in the other direction with a beam as well. My intent is to have one large open room on this rear corner with only one post in the room about 4 or 5 feet from the right side of the door in the picture. What is the minimum size/type of beam you would recommend for this? Do you know what the national code requirements would be for something like this? Any help or links to resources would be appreciated.

Answer
Hi Chris, a rule of thumb for beam spans, using a nominal 4" beam is as follows:  One inch of depth per foot of span.  So an eight foot span of bearing beam would theoretically be a 4x8, etc.  If your floor joists that will be tied into the beam are 2x10 then I would use a 4x10 beam, 2x12, a 4x12 beam etc. You should consult a structural engineer to verify beam sizes to meet your actual load requirements. I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com
    Questioner's Rating
    Rating(1-10)Knowledgeability = 10Clarity of Response = 10Politeness = 10
    CommentThank you for your quick and concise response!


  • Add to this Answer
  • Ask a Question

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.

©2012 About.com, a part of The New York Times Company. All rights reserved.