Install The Perfect Cupola

What You'll Need
Circular saw or jigsaw
Framing hammer
Measuring tape
Utility knife
Ladder or scaffolding
Roofing nails
Aluminum flashing
Loose shingles

Cupolas can be described as miniature roofed structures that straddle a ridge board at the center of a gabled roof. Cupolas come in many sizes and styles and can be open-air or glass enclosed. They can be functional by providing ventilation to an attic or garage, or they can be a purely decorative architectural element. Originally designed to ventilate farm buildings and carriage houses, cupolas are generally intended to add a rustic quality to modern suburban dwellings.

Before deciding on the size and location of a cupola, make sure that it will be in compliance with local building codes, many of which have height restrictions. Some home designs have a distinctive style that suggests, for example, a rural or a nautical influence. Select a cupola that merges with the overall architectural theme of the house. If the cupola is large enough, there may be sufficient space on the sides of the base to install siding material (wood shingles, wood siding, clapboard, etc.). If it is possible, you might want this material to match the siding used on the house exterior. 

A master carpenter can produce a hand-crafted custom built authentic wood cupola and a manufacturer can fabricate a wide variety of designs with synthetic, composite or metallic materials.

Scaling the Size of Your Cupola

Whether you are planning to construct a cupola or purchase and assemble a prefabricated product, there is a rule of thumb to help ensure that the cupola is scaled to enhance its visual effect from ground level. It is a generally accepted practice to make the base of the cupola 1 inch wide for every foot of length of the ridge board on which it sits. So if a garage ridge board is 20 feet long, the base of the cupola would be 20 inches on a side. Be sure to consider the height of the ridge also, and remember that it is better to have the cupola slightly over-sized but visible, than undersized and obscure. Here are some helpful tips to keep in mind when installing a cupola onto an existing roof.

Step 1: Remove the Shingles

Use a utility knife to remove enough shingles to accommodate the area of the cupola’s base so that the saddle is in contact with the plywood sheathing.

Step 2: Cut the Vent into the Plywood Sheathing

If the cupola is to be open to the attic or garage space below, use a jig saw or a circular saw to cut out the opening in the plywood. Do not cut into any structural members.

Step 3: Fasten the Cupola to the House Frame

Secure the saddle to the structural framing members (ridge, rafters) with screws or nails. Do not apply fasteners to the plywood sheathing alone.

Step 4: Install Flashing

Install flashing around the perimeter of the saddle and patch in shingles to cover the flashing.