Measuring and Non-Standard Openings

Six Numbers Decide Everything

Almost every ordering mistake we get called out to fix traces back to a measurement that was never taken. A door arrives, the old one comes off, and only then does anyone find out that the opening is an inch narrow or the headroom is short.

There are six numbers. Take them once, write them down, and every quote you collect afterwards is comparing the same job.

Measure the Opening, Not the Door

A garage door is larger than the opening it covers. It hangs behind the opening on the inside and seals against the stops, so the door is bigger than the hole by design.

Measure the existing door and order to that figure and you get something that does not seal at the sides. Measure the hole.

Width

Measure the finished opening from side jamb to side jamb, and do it three times: near the floor, at about halfway up, and near the top.

Take the smallest of the three. Openings are rarely parallel, especially where the jambs are fixed to masonry, and the door has to pass the tightest point.

Height

Measure from the floor to the underside of the header, again at three points: left, centre and right.

Take the smallest again, and note whether the floor is level across the opening. A slab that slopes for drainage, which is normal, means the bottom seal has to absorb the difference. If it is more than an inch across the width, say so up front, because there are seals that cope and seals that do not.

Headroom

Measure from the top of the opening to the lowest obstruction above it. Not to the ceiling. A water line, a bracket, a light fitting or a joist counts as the ceiling for this purpose.

A conventional torsion setup wants around twelve inches. Low headroom track brings that to roughly four and a half inches, at the cost of a double track and a slightly harsher run. Under that and you are looking at a jackshaft opener mounted on the wall beside the shaft.

Side Room and Backroom

Side room is the clear space from each side of the opening to the nearest obstruction, and you need somewhere around three and three quarter inches each side for the vertical track and brackets.

Backroom is the depth from the opening back into the garage, and the usual figure is the door height plus about eighteen inches so the opener rail and the trolley have room.

Squareness

Measure the two diagonals of the opening, corner to corner. If they differ by more than about a quarter of an inch, the opening is out of square and the door will show a wedge shaped gap along the top when it closes.

That is fixable with jamb packing, but it is far better to know before the door is ordered than to argue about it afterwards.

When the Opening Is Not a Standard Size

Standard single doors are eight and nine feet wide. Standard doubles are fifteen, sixteen and eighteen. Standard heights are seven feet, with eight feet common on newer builds.

Older housing predates that settling down, and around here you will find openings at seven feet six, at eight feet two, and at heights that stop well short of seven feet. There are three ways out:

1. Frame it down. Add jamb material to bring the opening to the nearest standard size. Usually the cheapest answer by a wide margin and it takes an hour or two.
2. Order to size. A made to order door fits anything, but expect a real premium and several weeks of lead time. Worth it when framing down would leave the opening too narrow to use.
3. Open it out. Widening to reach a standard size is structural, needs a correctly sized header, and needs a permit.

The Opening Somebody Already Widened

We see this often enough to have a checklist. A previous owner wanted to fit a longer or wider vehicle, cut the opening out, and did not put the beam back.

The tells are consistent. The header sags visibly along the top of the opening. The door binds at the top centre and nowhere else. There are stair step cracks in the drywall or stucco above the corners. And when you look inside, the track brackets are lagged into a single flat piece of lumber rather than into a real jamb.

None of that gets covered up by a new door. It gets repaired first, then measured, then the door is ordered to the repaired opening.

Call Cultureconnectinc at (657) 794-9630 and we will take the six numbers for you.