Homeowners often question what size garage door to get and how to make sure that their garage door is able to open uninterrupted. It all boils down to headroom, sideroom, and backroom. This week, we are laying out the basics about garage door opening alongside what terms homeowners need to know. Read on to learn what headroom, sideroom, and backroom are and why they are so important to keep in mind.


Headroom is a measurement that garage door professionals need to know when they are installing a door. Simply put, it is the distance between the top of the garage door and the ceiling. If there is a garage door opener on the ceiling (as there is in a majority of residential properties), then headroom is the distance between the top of the door and the lowest point of the opener system. Essentially, it is the amount of clearance a garage door has, so contractors know how low or high to install the door.


Sideroom is another measurement. However, this one focuses on – you guessed it – the sides of the door. It is the stretch of space from the edge of the garage door opening to the outside wall. This measurement helps dictate what kind of spring the door uses.


Backroom is the final measurement that impacts garage door opening. It boils down to the distance between the garage door opening and the back (opposite) wall of the garage. This measurement is very different for residential doors and commercial doors. Commercial doors need an extra five to seven inches worth of backroom. Additionally, the amount of backroom necessary changes if the owners install a garage door opener.

What Exactly Should These Measurements Be?

The short answer is “it depends.”

For a new build, homeowners and business owners can actually center the size of their garage around the garage door they want to buy. Luckily, doors nowadays are highly customizable. If someone wants a specific amount of headroom due to the size of their vehicles, many manufacturers accommodate those sorts of wishes.

The best way to ensure that there are no problems is to contact a garage door professional ahead of time. Qualified professionals are able to easily help homeowners determine what size and type of door work best for them.

For replacement doors in an existing space, there are quite a few standardly sized doors. Typically, even older homes are built with those measurements in mind. However, if a house is truly dated, it may require a more customized door.

If the only issue is a lack of headroom, there is actually an easier solution than a customized door. Most garage door dealers and professionals sell and install special “low headroom” kits. Ask your garage door professional about this option if the issue arises for you.