DIY Cupolas

The original purpose of a cupola was to create a ventilation device for a home or stable.

Build a cupola atop your house to add some charm.Build a cupola atop your house to add some charm.
However, if you do not want your cupola to serve a practical purpose, cupolas also make pretty decorative accessories that add charm to your home. This rooftop dome is often accessible from inside your home, creating an aesthetic touch and vantage point.

Use a table saw to bevel 2-by-6s. Cut them into 30-inch sections. Sand the eight pieces with your sandpaper; miter the ends at 45 degrees. Keep the leftover pieces that you beveled as you will use them later in the project.

Screw temporary plywood scraps to the bottom of the 2-by-6s to assemble the sill and soffit frames. The sill and soffit frames should be completely square and the scraps should not cover the corners of the frames.

Screw the sill to the cedar corner posts. Start with pilot holes on the four corner posts. Drill four 3-inch screws into the posts being sure that you drill two screws on each side of the miter joint.

Place the brick mold frames between the posts. Nail the beveled cut-offs behind the frames and then use construction adhesive to further reinforce. Make pilot holes where your screws will go in. Screw the bottom and sides of the vinyl brick mold frames to the posts. Screw the top of the frame to the posts.

Screw the vents to the back of the frames. Use 1/2-inch self-tapping sheet metal screws. Attach the soffit to the corner posts using the same process as you attached the sill.

Use a template to make the desired curve for your rafter. Make the same curve on all of your rafters. Join the rafters together by using a 6 1/2-inch piece of 2-by-2 wood as a hub. Screw the hub to two rafters and fasten the other two rafters by drilling 3-inch screws through the rafters. Place the joined rafters on a 26- by 26-inch piece of 3/8-inch plywood and drill 1 1/4-inch screws into the lower end of the rafters. Cut a round hole in the plywood base.

Drill the plywood to the rafters with angled screws, leaving a small gap between the rafters and sheathing. Center the roof on the vent housing and drill four screws through the soffit into the base of the roof.

Nail 4-inch-wide shingles to the roof, starting at the edge and overhanging the roof by about 3/4 inches. Leave a gap between the shingles. Reinforce the shingles with roofing cement.

Add curved ridge caps for a decorative purpose. Nail the ridge cap shingles over the shingle ridges. Add a large layer of roofing cement along the sides of the ridges. Cut shingles 5 inches long to match the curve of the ridge.

Fold a 9- by 14-inch piece of flashing around the peak of the roof. Cut the cap of the flashing. Fold the flashing back into a pyramid and add roofing cement. On the side of the cap that has an overlapping seam, drive a roofing nail through it.

Measure the angle of your roof by layering two boards over the roof ridge; screw the boards together. Mark two sides of your pressure-treated wood by placing the meeting point about 4 inches from the top of the wood and mark. Align the legs of the roof pitch gauge with the inside edges of your plywood saddle. Cut out the V shape.

Wrap flashing around the saddle construction. Use self-tapping screws down the seam. At the V shape in the wood, cut the flashing, fold the flaps into the saddle and use a screw to temporarily secure each flap.

Apply roofing cement to each sloped side of the saddle. Fold the flashing flaps over the cement. Drive screws through the saddle and roof. Use 2-by-2 cleats to fasten the saddle to the roof. Seal the ridge gap with roofing cement and caulk around the top saddle edge.

Attach the vent to the saddle with screws through the sill and inside the saddle. Drill screws through the soffit into the roof's base. Caulk over the screw heads. Paint or stain the screws or cupola as desired. Add polyurethane if desired.

Things You Will Need

  • Saw
  • Hammer
  • Drill
  • 8-foot cedar 4-by-4
  • 10-foot cedar 2-by-6s, 3
  • 8 foot 2-by-2
  • 4-by-8 sheet of 3/8-inch plywood
  • 4-by-8 sheet of 3/4-inch pressure-treated plywood
  • 8-foot pieces of brick mold, 4
  • 12-by-12-inch vinyl or aluminum gable vents, 4
  • Sandpaper
  • Shingles
  • 10-foot-long roll of aluminum flashing
  • 220-grit sandpaper
  • Galvanized screws (1 1/4, 2 and 3 inches)
  • 1/2-inch self-tapping sheet metal screws,
  • 1-inch galvanized nails
  • 3/4-inch roofing nails
  • Construction adhesive
  • Acrylic caulk
  • 2 tubes of roof cement
  • Stain
  • Paint brush
  • Polyurethane


  • For a lasting paint job, lightly sand the vents with 220-grit sandpaper first.
  • Ask a partner for help. This project includes many instances where you must hold a part in place while drilling or sawing; an extra pair of hands would be very desirable.


  • Be careful when you mount the cupola to the roof to avoid falls.
  • Always wear safety glasses and gloves when working on wood projects.

About the Author

Samantha Kemp is a lawyer for a general practice firm. She has been writing professionally since 2009. Her articles focus on legal issues, personal finance, business and education. Kemp acquired her JD from the University of Arkansas School of Law. She also has degrees in economics and business and teaching.