Expert: Robert Cummings, P.E. - 11/22/2008

Question
I'm trying to learn more about pan decks for a residential garage on a sloped lot.  Is this a common solution? I hear it mentioned, but several contractors I've encountered while aware of it seem unfamiliar. I'm trying to determine cost effective solutions and am trying to rough out costs of a pan deck approach to a 20' deep garage on a down slope (current 30 to 40% grade) vs retaining walls and fill vs extensive grading.  Searching on internet has not yielded much information either.

Answer
If I understand you right, you think perhaps the use of pan decking rather than another floor method would result in some advantages, the principal advantage being a lighter-weight application in above-grade construction and avoidance of retaining walls or retained earth cuts.  In that case you will of course have to provide piers or other supports for the decking.

The choice of decking is really a marriage between the structural engineering (which I am not) and the geotechnical aspects of the support design.  I wish I could help you further but you really should consult a structural engineer about the detailing of the decking approach.

You should not overlook the garage access also.