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Exterior Radius (Arch) Top Shutter Measurement

Crafted for Future Generations
Rectangular shutter measurement

True Half Circle

Radius top shutters are measured much the same way rectangular shutters are, with the additional requirement of a Short Side measurement. The Short Side measurement is the only extra piece of information required to display your shutters in the Shutter BuilderTM.

The Shutter BuilderTM calculates the Radius and places it in the description of the shutter for additional design consideration.

First determine what kind of arch top shutter you want. There are three basic types of arched shutters.

  • True Half Circle Top
  • Shallow Arch Top (eyebrow)
  • Gothic Top

The shutter pair to the right is constructed as a True Half Circle Top. Measure the Pair Width or Opening Size and the Height at the center. The difference between the Height of the shutter and the point at which the curve starts is called the Short Side measurement. Because this difference in our example is 18" and Leaf Width is also 18" we know this is a True Half Circle with the Radius equal to 18". The start of the short side measurement is often difficult to measure exactly due to it subtle transition from the vertical Stile. In practice if the difference is very close to the leaf width it is a safe assumption that you have a Half Circle top shutter.

Shallow Arch Top (Eyebrow)This shutter pair is constructed as a Shallow Arch Top, also known as an eyebrow due to the gentle rise of the arch. Measure the Pair Width or Opening Size and the Height at the center. The difference between the Height of the shutter and the point at which the curve starts is the Short Side measurement. Remember, only the Short side is required for the Shutter BuilderTM. The Radius for this shutter pair can be determined with a simple formula and is provide for additional design consideration.

This formula can be used on any continuous radius about a center line.

 

Radius =   ½ (Difference in Height2 + Leaf Width2)
  Difference in Height


Radius =   ½ ( 62 + 182)
  6


Radius =   30"

 

 

 

 

 

 

 

The last shutter pair is constructed as a Gothic Arch Top. Measure the Pair Width or Opening Size and the Height at the center. The difference between the Height of the shutter and the point at which the curve starts is the Short Side measurement. Remember, only the Short Side is required for the Shutter BuilderTM. The Radius for this shutter pair can be determined with the same formula as above with one change. Because the top of this shutter pair comes to a point and the formula is only for continuous radi about a center line, rotate one of the shutter leaves to rest on its edge as shown to the right. Extend the imaginary line of the curve to the right until it intersects with the horizontal edge. Notice that the drawing now looks like a Shallow arch top. Input the numGothicbers and the formula becomes,

 

Radius =   ½ (Difference in Height2 + Leaf Width2)
  Difference in Height


Radius =   ½ ( 182 + 282)
  18


Radius =   30.778"

After obtaining the measurements and calculating the radius, the practical step of creating a Template to place in the window opening or on existing shutters is a simple matter. This final step can remove any doubt about what may appear to some as a complicated shutter.

If your window situation requires special or custom hardware we have a Blacksmith who can solve any hardware problem. Please call and speak to our staff about any hardware questions.