How To Measure For a Factory-Built Fireplace Door

An example of an unfinished zero clearance fireplace

When replacing a fireplace door for your zero-clearance, prefab, or factory built firebox, its important to get an exact fit. Although this may seem tedious or difficult, it is nothing more than a matter of removing old tracking and then finding "opening dimensions". The best way to avoid poor performance of your new door is to get an exact fit, then choose options and styles to accent the function or design of your fireplace. During this process of measurement, please use a metal tape measure that wont stretch, and note any model numbers or manufacturer name. Do You Have a manufacturer or model number handy? Click here to check out our database!

All glass fireplace doors & screens for zero-clearance are designed to either overlap the opening, or fit inside the opening (as a flush fit). Its recommended that both inside-fit & overlap-fit fireplace doors meet the following guidelines:

  1. There is a suitable and clean mounting "track" all around your opening
  2. The Mounting surface should be level & surround materials in good shape
  3. The firebox opening should be square since our fireplace doors are made to be exact
  4. Any out of square conditions on the opening will be exaggerated, or will prevent proper installation of your fireplace door.


I Have A Zero-Clearance, Prefab, or Factory Built Metal Fireplace:

Below are some examples of what a factory built fireplace looks like. Yours may be different, but the idea is the same - a metal box that fits in a hearth. We carry a large selection of fireplace doors for factory built fireplaces here.

A zero-clearance factory built firebox installed in a hearthA zero-clearance factory built firebox without hearth around it


Let's Begin By Measuring Various Widths & Heights Of Your Fireplace:

You must measure for the fireplace door in a few places. This ensures that the fireplace door will fit in fireboxes that may not be perfectly square. For more information, read on or check out the Video Measuring Guide or the PDF Measuring Guide.

Measuring for a zero clearance factory built fireplace door in various places

Lets first remove any tracking, bars, screws, or other parts in the way. Take the old doors off, along with all the hardware used for holding the doors or mesh onto the firebox. We need a clean opening area to measure in. While you're at it, try to find your manufacturer and model number on a sticker somewhere. Need help understanding how to read a tape measure? You can read or watch our full tape measuring guide here.

In order to determine the width of your firebox opening, we suggest that you measure it width on top, middle, and bottom. Do not measure finish material, only the opening. Use the smallest number of these measurements. In order to determine the height of your fireplace opening, we suggest that you measure it on the right side, left side, and middle. Also use the smallest number from those measurements. Your 2 smallest measurements will be the opening dimensions. Glass fireplace doors installed as overlap fit will be mounted to the face of the fireplace and need to rest in the existing "opening track". Fireplace glass doors installed as inside fit will be mounted inside the opening for a flush appearance. Always choose exact opening measurement as requested on the product builder. Do not deduct anything from your measurements otherwise your door will be built to small or might not fit.

If still unsure, send us a picture of the fireplace. This will help us to make sure you get the right fitting door for years of enjoyment. We are available at (888) 986-1535 or directly at [email protected] to help you in any steps of this process.


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