Expert: Bruce E. Johnson - 9/1/2008

Question
There was an addition added to my huse. The original weight supporting wall was left in place. I would like to open this wall to the adiition. I have heard that because the wall is supporting the roof trusses that this is not practical. I wish to minimize costs but still wish to expend the rooms. What different methods could be used. It is difficult to explain, the addition was added to the back of the house. the inside original wall is thirty foot long. I think I want to open this space up with little or no center support. Plumbing and electricity aside I really have not spoken to anyone who would consider this. They just want me to live with the openings created by the old windows and work around those. The addition is support by the same wall as the original house.

Answer
Hi ralph, basically you have to shore up the roof trusses or rafters that bear on the wall in question and then install a big enough header or beam to support the size opening you want.  Remember the longer the span the bigger the beam.  As a rule of thumb for wood beams is: for every foot of span the 4X beam needs one inch of thickness.  In other words an eight foot span would require a 4x8 beam etc. So that's about it.  Shoring up the roof while the work is done isn't too difficult, a few studs (one under each truss or rafter) supporting a flat 2x4 up against the ceiling, similar to a framed wall.  Give yourself enough room to work on the wall you are repairing.  I usually have the drywall off the walls and have a good idea of what it is going to take to install the new header before I do any structural work and have all my materials cut and ready to go before removing any structural elements. I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com