How to Install a Cupola on a Pitched Roof

Lay two 1-by-4 boards on either side of the peak of your roof so they protrude and intersect one another. Secure the intersecting boards with screws. Trace and mark on the boards the angle of the intersecting edges. Use a level to draw a plumb, vertical line at the very center of the intersection.

Mark the center of the sides of the cupola that you will cut to fit over the roof peak. Use a square to draw straight, vertical lines down the center of each side.

Trace the shape of the peak onto the cupola sides. Center the intersecting boards on the cupola by lining up the vertical lines you drew on each. Position the boards so the inner edge of each leg matches up with the bottom corners of the cupola. Trace along the inside edges of the boards.

Cut out the traced peak shapes with a jigsaw.

Prepare the section of your roof peak for installation. You can remove the area of shingles where you will install the cupola, but this is not necessary. Measure and cut lengths of 2-by-4s to be attached to the roof and to fit on the inside of the cupola. The cupola will be attached to these boards. These boards are only necessary at the sides of the cupola that were cut to fit the peak. This means that you will need four boards in total, two for each side of the peak and for both cut sides of the cupola.

Wrap the boards in adhesive water and ice barrier film. Screw the boards to the roof with rust-resistant screws.

Set the cupola over the boards. Attach the cupola to the boards with screws or a nail gun. Place screws or nails every 10 to 12 inches. Caulk the screw or nail heads.

Caulk around the entire seam where the cupola meets the roof.