June 29th, 2018

Rough Opening Measurement Calculations 

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It is not uncommon being a few inches off the correct measurement for a door, frame or opening. At Ahner Commercial, we've realized people who maybe unfamiliar with this industry do not have an understanding with the measuring of rough openings and how they correlate to the correct door and frame sizes. Well we can help you! This process on how to properly estimate your rough frame opening can be explained below. The various intricate amount of materials and sizes may make the process seem difficult to learn at first but let us assure you, you can do it!  
Have a question or need assistance? Give us a call at our Office, (419) 960-7307.

Rough openings can be calculated as follows:

For masonry frames:  Add 4" to the width of the nominal opening size.
                                        Add 2" or 4" to the height depending on the head size.
                                        Add 1/4" for spacing to height and width.
Ex. A 3070 frame with a 2" head would get an R.O. of 40-1/4" x 86-1/4"
      A 3070 frame with a 4" head would get an R.O. of 40-1/4" x 88-1/4"
      A 5068 frame with a 2" head would get an R.O. of 64-1/4" x 86-1/4"

For drywall KD frames:  Add 2" to the width of the nominal opening size.
                                            Add 1" to the height of the nominal opening size.
                                            KD frames fits over stud and drywall by 1".
                                            KD frames always have a 2" head size.
Ex. A 3068 frame would get an R.O. of 38" x 81"
      A 2868 frame would get an R.O. of 34" x 81"
      A 3070 frame would get an R.O. of 38" x 85"