If you’re replacing a sliding glass door, it’s critical to measure accurately before ordering your door. Any replacement door contractor or installer must do a critical measure before even placing an order for your new sliding glass door. There’s an old saying that goes, “Measure twice, cut once.” Why? Because you want to make sure your measurements are correct before you cut into your home OR order a door that may not be the right size. An inaccurate door measurement could result in:

  • needing to reorder your door
  • needing to adjust your rough opening and/or threshold
  • a drafty, non-energy efficient door

All of these things can be extremely costly, which is why it’s imperative that you measure for your replacement door properly!

measure for sliding glass door replacement

How to critically measure a sliding glass door for replacement

  1. If you’re looking to replace your current sliding glass door, your door contractor or installer will want to determine the “rough opening” of your door. The rough opening is essentially the hole that your replacement sliding glass door will fit into.
    *Note: The rough opening for a sliding glass door may vary based on the style of your home’s current sliding glass door, the trim, and the construction of your home.
  2. Your Horizontal Rough Opening Measurement: Your contractor or installer should measure horizontally across the top, middle, and bottom of the rough opening. It’s possible that all three measurements will be the same. If they’re not, you’ll want to use the smallest of the three measurements to ensure you’re getting the best fitting door for your rough opening.
  3. Your Vertical Rough Opening Measurement: Your contractor or installer should measure vertically in three different places (left, middle, & center). Again, you might find that all measurements are the same, but if they are not, you should use the smallest of the three measurements.

sliding glass door vertical measurements

At Coastal Windows & Exteriors, we measure with a 1/8” allowance around the rough opening, this gives us leeway for openings that aren’t plumb and square. By doing this, we make sure that your new sliding glass door will perform up to its tested energy efficiency rating.

Why should you care about measuring for your sliding glass door replacement?

  1. Energy Efficiency – A critical measure is crucial for making sure your new door won’t be drafty and a cause of energy loss
  2. Aesthetics – Make sure your door looks right for your home. It should blend in seamlessly to your home’s design, not look as if it was forced to fit.

At Coastal Windows & Exteriors, taking accurate measurements is vital to making sure we’re custom fitting your new sliding glass door to your home. When we measure a sliding glass door for replacement, we review the project in detail so we can ensure proper installation and maximum energy efficiency.

We consider a critical measure part of quality control, because the lead sliding glass door installer can identify any potential problems while measuring for your new door.  A critical measure is a part of our system of checks and balances to make sure our homeowners have the best experience possible.

Our sliding glass door installers have years of experience and a trained eye.  That being said, a correctly measured sliding glass door is just as important as a correctly installed sliding glass door, but that is a discussion for another day.

If you have additional questions about how to accurately measure a sliding glass or patio door for replacement or about patio doors in general, please don’t hesitate to contact us at any time. We can be reached at (888) 812-2783 or you can email the owner, Stephanie, directly at svanderbilt@mycoastalwindows.com.