Try spraying WD-40 on the spots where the wasps like to build....it works to keep swallows from building nests....maybe it'll work for wasps too.
Linda C

We seem to get alot too.

Paint the ceilings of your porches, landings sky blue. They won't nest there.

CC

For some factual information, go to: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7450.html