Step-by-step guide to measuring your garage door opening for a replacement door. Width, height, headroom, and side room — what to measure before you order.
If you're getting quotes for a new garage door, knowing your opening's measurements helps you compare apples to apples and spot a company that's cutting corners. You don't need to be exact to the millimeter — that's our job — but understanding the key dimensions makes you a smarter buyer.
Grab a tape measure and a notepad. You're measuring five things: opening width, opening height, headroom, sideroom, and backroom (ceiling depth).
Measure the rough opening width at the floor, the middle, and the top — use the smallest of the three. Then measure the height from the floor to the top of the opening the same way. A standard single-car door is 8 or 9 feet wide by 7 feet tall; a standard double door is 16 feet wide by 7 feet tall. Most Fort Collins homes have one of these, but custom sizes are common in older homes.
Note: the door itself is sized to the rough opening, not the finished framing. This is where DIY measurements get people in trouble — order the wrong size and nothing fits.
Headroom is the distance from the top of the opening to the lowest obstruction on the ceiling — a joist, a light, ductwork. You need at least 10–12 inches for a standard torsion-spring install, and more for a high-lift or tall door. Low headroom? There are low-headroom track options, but they cost more and limit spring choices — tell us upfront.
Sideroom is the distance from the edge of the opening to the wall on each side — you need at least 3.5–4 inches on each side for the vertical tracks. Backroom is the distance from the opening back into the garage — you need the door height plus about 18 inches for the horizontal tracks to extend. A standard 7-foot door needs roughly 102 inches of backroom.
Spring sizing, track configuration, and opener compatibility depend on door weight, wind-load requirements, and your opener model — these are not DIY measurements. That's why we measure on-site before ordering. But having your five dimensions ready means we can give you an accurate ballpark over the phone and a faster install. Call 970-408-9827.