Expert: Ted Barnhill (Principal, Design45 LLC) - 7/28/2007

Question
I have an attached garage 24'x30' built with common trusses.  My outside wall had concrete poured alongside it,(don't know why) below the level of the garage floor by atleast 18".  It appears to have created a scissor effect and damaged that whole block wall.  Garage floor seem to have cracked and is pushing out while concrete from outside is pushing in. I talked to a contractor who would like to lift the walls off the foundation and rebuild the block wall.  Since I have trusses where is the best way to secure it.  Sounds like he was going to just build a wall under the trusses more towards the center of the garage to lift it.  I didn't think you're suppose be able to do that.  Is this common or is there a better way to lift it???

Answer
Temporary shoring is case-by-case, depending on many factors.  Generally, trusses are designed to bear at a specific point and shouldn't be unduly stressed, e.g., in the middle of a chord.  Sometimes trusses become damaged in ways that are hard to see and lose strength.  By the way, I didn't understand the origin of your foundation problems - be sure that you and the contractor know whether this is a frost heaving problem, settling problem, water problem, or something else before beginning.  Best of luck with your project.