The Philadelphia Shutter Company

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Radius (arch) top shutter measurement

drawing of windowMeasuring for interior shutters and hardware is an important step in your selection process. The key point to understand is that shutters and hardware are designed to be used. While it is true that many shutters are not opened and closed as they were in the past, the best way to approach this task is to proceed with the intention of having fully working shutters. Properly sized shutters are easier to install and have the truest appearance.

Designed to be operated from within a building, interior shutters are placed next to the sash (the frame that holds the glass) in the closed position and locked from inside. In this example the Slide Bolt is positioned on the lower mid rail or Lock rail, purposely placed here to be accessible when the lower window sash is raised. Lock rails below the sash meeting point are an indication of authentic working shutters.

Shutters are unlocked from the inside and pivoted outward on hinges until they rest on the surface of the structure. The shutters remain secured in the open position by some form of hardware, typically by a shutter holdback, also called a shutter dog.

The first step in shutter design is to take careful measurements of the opening where the shutters rest in the closed position next to the window sash. As indicated by the red arrows in the image on the right, take several measurements along the window frame. For operational clearance, subtract 1/2" from the measurements to find the Pair Width and Height of the shutters. Typically, openings are not exactly square nor do they have the same measurements as apparently identical neighboring windows. For this reason you should take at least two measurements for the Pair Width and Height of each window. Using the smaller of the width or height measurements will eliminate field trimming of the finished shutters.

The second step is to determine the Throw and hardware Offset. Understanding these two terms and how to measure for them is a straightforward and simple process.

When a shutter is opened or closed there are two types movement. The first and most apparent is the pivoting motion on the hinge axis, from the closed position in front of the sash to the open position to the left or right of the window (A). The second motion is the shutter moving from within the window well outward to the surface of the interior wall. This outward motion can be as many as seven inches (B) depending on how deep the window is inset. Because this movement can be significant, the parts of a shutter hinge set have a design component called Offset. The combined offset of the strap hinge and the offset of the pintel is called Throw. The deeper the window is inset into the wall, the greater the Throw.

  drawing of Shutter open and closed positions


drawing of Hardware offset and throw

To measure the Throw place a straight board across the window and let it rest on the surface of the interior wall. Take the measurement from the window casing to the back of the board (red part of the ruler in the image below). This measurement is the Throw. Half of this measurement is the hardware Offset for a hinge set.

drawing of How to measure the throw

Just as some windows are set deep into the window well, others are flush if not slightly proud (above the surface) of the interior wall.  Shown below is a Lag Mount Pintel and zero Offset strap hinge. All of the examples so far are called Surface mount hinges. As their name implies they mount to the surface of the window casing.

Lag mount pintel and zero offset

Another group of hinges is called Mortise hinges or Jamb mount. They function like standard door hinges and are fastened to the edge of the shutter and edge of the window opening.

drawing of Mortise hinge or jamb mount

One of the last items to note when measuring for shutters is the material use for the building's interior walls. Specific hinges and holdbacks are used if mounting into brick, stone, or frame construction.

The following is a checklist of the information to obtain when measuring for shutters: 

  • Shutter Pair Width
  • Shutter Height
  • Throw
  • interior wall Material
  • Note the hinge mounting area and select Surface Mount or Jamb Mount

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.