What is a Weathervane?

A weathervane is an instrument for showing the direction of the wind. They are typically used as an architectural ornament to the highest point of a building. Although partly functional, weather vanes are generally decorative, featuring an ornamental design with letters indicating the points of the compass. Common weathervane designs include roosters, eagles, horses, blue heron, boats and ships, arrows, and more.

The design of a weathervane is such that the weight is unevenly divided on a vertical shaft so the vane can spin freely in the slightest breeze. The side with the larger surface area is blown away from the wind direction. In other words, the arrow, or front of the weathervane, points into the wind, not with the wind. If the vane were designed with the weight evenly divided on the vertical shaft, the vane could not function properly.

Nowadays, weathervanes take on on many fancy and unique designs that may not always tell the real direction of the wind. These designs are more decorative and were not intended to be accurate, but ornamental.

In order to receive an accurate wind reading, the weathervane must be located well above the ground, away from trees, buildings, and other objects that hinder and interfere with true wind direction. As stated above, however, most weathervanes today are used purely as a decorative focal point, and are installed where the owner chooses will look the most prominent, not where it will get the best wind reading.

What is a Cupola?

The definition of a cupola can take on many meanings.

1. cu•po•la (kyou' puh luh), noun 1. Archit. a. A light structure on a dome or roof, serving as a belfry, lantern, or belvedere.  b. a dome, esp. one covering a circular or polygonal area.  2. any of various domelike structures.  3. Foundry. a vertical furnace for melting iron to be cast. [< It < L cupula, see CUP (from Latin, meaning tub or cask) + ULE. (from Latin, meaning small)]

2. cu•po•la  a dome, especially a small dome on a circular or polygonal base crowning a roof or turret.



Cupola and Weathervane

I consider cupolas to be ornamental structures placed in a prominent position, typically on top of a roof, dome, or turret.  Cupolas appear to be miniature structures in themselves. Cupolas tend be be used more as a decorative structure nowadays then a functional venting structure, which ridge vents now serve the purpose of. Cupolas can still be used for venting barns or other buildings with excess heat build-up, but most often they are crowned on homes, garages, barns, sheds, and gazebos as a decorative focal point to mount a weathervane or finial on top of. Cupolas have been around dating back to 8th century Islam, and gained popularity in Europe in the 17th century. Why not keep this history alive on your home with a beautiful cupola?

How to Choose the Proper Size Cupola

When choosing a cupola size, it is strongly recommended to get atleast 1" of cupola width for every foot of unbroken roofline. Going up to 1.25" is typically your best option.

If you choose a cupola and do not follow the industry standard, you can end up with a cupola that looks like this....

However, when the rule of thumb is used when choosing a cupola size, you end up with a beautiful finished product.