To save you the trouble, we ship our Cupolas with the base pitch already cut out of the base to conform to the pitch of your roof.  So we need to know your roof pitch.  Here's how to determine it:

The measurements are taken from on top of the roof.  Simply mark a level at 12", hold it perfectly level and measure from the roof surface to your 12" mark, this will give you the RISE. (Be careful with this method as a roof with many layers of shingles, or any type of roofing that is irregular can give you less than precise results).

So, for example, if you measured 7", the pitch of your roof is 7/12, pronounced "seven over twelve".