Size Measurement Guide: What Every Homeowner Should Know

2024-01-05 6 min read

Why Accurate Measurements Matter

When it comes to garage door installation, accurate measurements are absolutely critical. A door that's too small will have gaps that compromise security and energy efficiency. A door that's too large simply won't fit. Either mistake can be costly and time-consuming to correct.

At Garage Door Belfair, we always perform our own professional measurements, but understanding the basics can help you communicate with contractors, plan renovations, or simply better understand your home's specifications.

Essential Measurements for Garage Door Installation

1. Opening Width

Measure the width of the garage door opening at its widest point. Take this measurement at floor level. Standard single-car garage doors are typically 8-9 feet wide, while double-car doors are 16-18 feet wide.

2. Opening Height

Measure from the floor to the bottom of the header (the framing at the top of the opening). Standard residential doors are 7-8 feet tall, though custom heights are available.

3. Side Room (Left and Right)

Measure the distance from each side of the door opening to the nearest wall or obstruction. Most standard garage door systems require at least 3.75 inches of side room on each side for track installation. This space is also called "side clearance."

4. Headroom

This is the distance from the top of the door opening to the ceiling or lowest obstruction (like a joist or light fixture). Standard torsion spring systems require 12-15 inches of headroom. Low-headroom hardware is available for tighter spaces but may cost extra.

5. Backroom (Depth)

Measure from the inside of the door opening to the back wall of your garage. This determines what type of opener and track system will work. Most installations require the backroom to be at least equal to the door height, plus 18 inches.

Measuring Tips for Accuracy

Use the Right Tools

Take Multiple Measurements

Garage openings aren't always perfectly square. Measure width at both the top and bottom of the opening, and height at both sides. If measurements differ, note the smallest dimension, this is what the door must fit through.

Check for Level and Plumb

Use a level to check if the floor is level and if the sides of the opening are plumb (perfectly vertical). Unlevel floors or out-of-plumb openings may require additional work before installation.

Common Measurement Mistakes to Avoid

  1. Measuring the old door instead of the opening: Always measure the actual opening, not the existing door.
  2. Forgetting obstructions: Note any lights, pipes, or other items that could interfere with door operation.
  3. Ignoring garage layout: Consider how the door will travel up and back. Will it interfere with anything?
  4. Not accounting for weather seal: Remember that weatherstripping will take up some space.

Standard Garage Door Sizes

Single Car Garage

Double Car Garage

RV and Commercial

Custom sizes are available for oversized vehicles, RVs, boats, and commercial applications. These typically range from 10-12 feet in height and can exceed 20 feet in width.

When Measurements Don't Fit Standard Sizes

If your measurements don't match standard sizes, don't worry. Custom garage doors are readily available. At Garage Door Belfair, we work with manufacturers who can create doors to virtually any specification. Custom doors may take longer to order but provide a perfect fit.

Let the Professionals Measure

While DIY measuring can give you a general idea of what you need, we always recommend having a professional confirm measurements before ordering a new door. At Garage Door Belfair, our free estimates include precise measurements by experienced technicians who know exactly what to look for.

Ready for a new garage door? Call us at 360-226-7649 to schedule your free in-home consultation and professional measurement.

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