Cupolas come in three sections, Roof, Middle and Base. The "base" is the bottom section of a cupola. If your roof is steeper than a standard 10/12 pitched roof, it may be necessary to add an "extension" to your cupola's base section. A base extension isn't a separate piece, it's just a taller base section allowing more room for cutting the the angle for a steeper roof. This option is available for our Royal Crowne and Good Directions cupolas.
All of our cupolas will fit up to a 10/12 roof pitch, except for the Shed Series cupolas that will fit up to a 7/12 pitched roof. If you know how to figure out the "pitch" of your roof, great! But, if you're not sure how to do it, we recommend a simple device called a Johnson Level, Pitch and Slope indicator for under $10. Here's a LINK where you can buy one on Amazon. You might also find something similar at Home Depot or Lowe's.
If your roof pitch is 10/12 or less (or 7/12 or less for a Shed Series cupola), you don't have to add extension to your cupola order. However, if your roof pitch is more than 10/12 (or 7/12 for a Shed Series cupola), you can select extensions from the drop-down menu above. One extension is required for every two inches over the standard 10/12 (or 7/12) pitched roof. For example, if your measurement is a 12/12 pitched roof, you should select one extension. If your roof pitch was 14/12 you'd need two extensions.
Here's how carpenter's determine roof pitch (if you're interested):
To find out what the "pitch" of your roof is, you would put a carpenter's square on the edge of your roof, with a level sitting on the top edge of the square perfectly level. Using the square, measure out 12" horizontally from the roof, now look at the square to see how many inches there are vertically from the top of the square down to the roof. The graphic at left shows a roof with a 7/12 pitch roof.
If your roof pitch is steeper than 10/12 (or 7/12 for shed cupolas), you can extend the base of the cupola to allow for the steeper cut that will be made on the sides of the cupola to fit the roof.