Expert: Ted Barnhill (Principal, Design45 LLC) - 12/5/2007

Question
We have a single story log home on crawlspace concrete foundation and want to add a 2nd story. Foundation is 5 1/4"thick on 14" wide footer, depth unknown (yet). Also unknown (yet) is local soil capacity. What do I need to know to safely add this 2nd story, here in rocky western MT?
Also, I'm no builder, but a hands-on engr and this 2nd story is from an existing loghome materials supplier. Could I do this addition myself?
Thanks,
John

Answer
John,

That sounds like an ambitious project for a "non-builder".  To take it on safely, I recommend at a minimum that you consult with a structural engineer on an hourly basis to work through the major structural issues.  These include the foundation design, shear walls, and floor/roof support.  

To determine the structural adequacy of your foundation, you are correct that you'll want to know the soil bearing, as well as the dimensions of, and extent of reinforcing in, your existing wall.  5.25" is thin.  Depending on the span of your floor systems, the loading for a two story home may be able to be carried on a 14" footer.  If your second floor is not "clear span" from exterior wall to exterior wall, you'll need to accomodate new loading in the center of the house, probably with new footers.

Once you have resolved the major structural issues, check out some books on log construction.  It is straightforward, and well-suited to advanced do-it-yourselfers.  However, you'll be building at quite a height.  Be sure that you are comfortable with required roof bracing, and procedures for working safely at heights.

Good luck,  Ted