How to measure: the size of garage doors vs. the size of opening

Two of the most frequent (and important) questions everyone who is buying garage doors comes across are:

• how to measure my garage door opening,
• what size of garage doors do I need based on the size of the opening.

We’ll take a look at both of them.

The most important advice is to measure the opening thoroughly, do it twice or trice, and only then do the ordering. It doesn’t matter if you will need one of the standard garage door sizes or custom made ones; if your measurements are sloppy, the garage doors won’t fit and you will have to send them back or adjust the door opening, none of which is fun. So be careful with the measurements and save yourself a lot of headache later on.

How to measure the size of garage door opening?

You have to take exact measures of the width and height of the brickwork opening (no. 1 and 2). Since the walls, the floor and the lintel may not be completely straight, you should measure both width and height at three spots – at each side and in the middle. If the sizes at different spots vary, you will have to either break off a part of the bricks where the opening is smaller or add some pieces of bricks where it is wider. But in most cases the size of width and height of the garage door opening should be approximately the same.

In addition to the opening itself you need some more information. You need to measure the space from the lintel to the ceiling (called the internal headroom, no. 3). It depends on the type of the door you are going to install but for many garage door types you will install a part of opening mechanism on the ceiling so you need this information. Also you need to measure the length of the free space on the ceiling called headroom (no. 5).

And finally you have to measure the internal reveals (no. 4) – this is the width of the wall from the garage door opening to the first wall on the right and left side. You need to measure this from the inside of the garage too, of course.

Additionally you have to note any type of obstacle on the walls or ceiling that may cause trouble for installing or opening/closing the door, such as lights, electric sockets, electric or gas meters, or anything else sticking out of the wall or being in the wall. Also make a note of any peculiarities that may have impact on the installation and use of the garage doors.

Choose the correct size of the garage door

You’ve got all the sizes that you need. Now you have to use them to order your door. With any garage door manufacturer the information gathered above should be enough to order the right size of the doors. If you provide them with those numbers, they will be able to tell you the size of the door frame and the doors that will fit your opening.

However, there is another thing that may be smart to do when measuring the opening. Our imperial system (with feet and inches) is not as precise as the metric system with centimeters and millimeters. If you have a meter with millimeters on it, note that numbers also. It may be helpful to the seller or manufacturer to provide you the exact garage door size that you need.

Take your time when measuring your garage door opening size. The effort you invest into getting the precise dimensions of the opening and also noting any special circumstances that may be affecting installation and use of your garage doors will be payed back with dividends when you receive your garage doors and get them installed without any problems.