peter wrote:

I just had my roof replaced but I want to check the contractor did the job
correctly.

I'm concern about

the minimum width of roofing shakes (cedar)
the minimum distance between the edge of one shake and the edge of the one
below/above it
the minimum thickness

Is there a national guideline for this type of thing, or where should I go
look for a rules that applies to my house (in seattle)? The State? The City?
The manufacturer of the shake?

(D) There was an installation sticker w/ every bundle of shakes.

Depending on what particular shake you had, the setback is somewhere
between 5 and 9 inches. The minimum width is whatever is in the
bundle. Same goes for the thickness. A good installer will reject
wildly out of average shakes as he goes. Remember, if you're really
talking shakes as opposed to shingles, they're split so variation is the
norm.

I'd also note that if you had concerns, the time to have raised them was
while the work was in progress....