When Do You Recommend Installing A Cupola?

Ai recommends that a cupola be built only if a loft  is desired. A cupola added on top of the larger domes, 40', 45', or 48'  creates enough headroom so a third floor loft can be built. A ships ladder is installed to access the loft from the second floor. For example in a 40' dome with a cupola, a third floor can be built so you can stand in the loft and see out the windows.

A cupola is not available on the 22' or 27' domes.  To vent hot air out of the top of the 22' and 27' domes, install an exhaust fan in the top of a second floor interior wall and a vent in the top center of the dome.  The interior wall ducting for the fan can run thru the vertical second floor wall and second floor joist and vent out under an entryway or dormer.    Second floor window dormers are not available in the 22' or 30' domes. 

Does a cupola change the

structural integrity of the geodesic dome?

No. In hurricane areas install impact resistant glass in the cupola windows to prevent the glass breaking from the force of the winds or debris being slung into the glass.

The cupola does not weaken the rest of the dome, but the cupola is more vulnerable to wind loads because it sticks up at the top. In high winds the overhang panels could come off. They are nonstructural and would simply be replaced after the storm.

The following is an overview of the Cupola Construction.

The top five component panels of the dome make up the cupola top with overhang panels (eave panels) added on site.

• The topside exterior of the five pentagon panels of the cupola is prefinished steel reinforced concrete. These panels have seven inch thick E.P.S. insulation.

• The overhang/eave panels consist of 3 1/2" thick E.P.S. wrapped in steel mesh. The underside of the eave panels have prefinished concrete.

• The topside and edges of the eave panels are stuccoed onsite.

The actual cupola assembly instructions consist of six pages. The subcontractor and four laborers take two to three days to build and assemble the cupola. Yes some form of hoisting mechanism is needed to lift the cupola panels to the top of the dome. The cupola is made by installing the top five panels on top of a five-sided concrete wall that contains the windows.

• The first step is to form and pour a concrete beam around the top opening which reinforces the opening.

• Next, set 2x4 window frames in place on top of the beam.

• Then form and pour a concrete column at each of the five corners.

• Finally, install the five panels and there C1 extensions on the top of the wall and concrete the seams.

• At anytime thereafter you may install the windows and finish the interior.

Third Floor Loft Heights And Square Footages

Please see the floor planners in the back of the Stock Floor Plan Booklet for loft heights and square footages. The outline of the third floor loft matches that of the cupola. The 22', 27, 30', 34, & 36' domes cannot have a third floor loft.

If I do not install a cupola on the dome,

how does the hot air and moisture get exhausted from the dome?

In a vertical wall near the top of the dome, in bathrooms, at stove, microwave, clothes dryer and at top of the dome install exhaust fans that can be turned on to exhaust hot air and moisture. Use galvanized ducting for the exhaust fan ducting. It extends thru interior walls, through the floor joist and vents out under an entryway or dormer.