Expert: Bruce E. Johnson - 1/26/2010

Question
I am considering buying a two story home with very small square footage because it meets all my other needs. One thing that I would really like to do is extend the wall that divides my back yard space from my kitchen and dinning room out a few feet. There is an over hang from the second story so I would not have to build the roof out but I have concerns about support beams. The wall is about 20 feet long from one end of the kitchen to the other end of the "dinning room area". How many of these beams am I likely to run into?  

Answer
Hi Desiree, where your outside wall exists at this point in time is where your roof structure sits.  These are "bearing walls".  A bearing wall doesn't even have to have any beams in it if it is a solid wall, with studs at 16-24" apart.  If there are windows in the wall, they have "headers" above them that are basically beams made to span over the open area of the window.  If you want to tear out this bearing wall and move it back a few feet then you still need to support these rafters somehow.  If the roof is hand framed with rafters, you might be able to move the bearing location of the rafter without a lot of problems but where the birdsmouth is cut into the rafters at the existing location you may need to reinforce the rafter where the birdsmouth notch is cut into it.  If your roof is manufactured trusses then your bearing point will always be where the wall is right now. Manufactured or "engineered" trusses are designed to bear on a certain location and if that location is changed then the design may not work without maintaining the same bearing point.  This is where you will need a beam, to support the trusses where the wall use to be.  Twenty feet is a long span.  I recommend that you use a double LVL laminated beam sized to meet your requirements.  But you will have a header sticking down into the opening of at least 16".  Once you support the roof properly you can put the outside wall wherever you want it.  I hope this information helps, please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com.