Two single garage doors or one double? Start with the post between them

Plenty of two-car garages in Howard County were framed with two single doors and a post standing between them. It suited the cars of the day. It suits a full-size pickup less well, and anyone who has backed one through a single opening with the mirrors folded knows the margin. So when both old doors come due at once, the question comes up on its own. Keep two singles, or open the wall up for one double door?

The answer starts with the post. What it holds up decides whether it can come out at all. Once it is gone, the opening that is left decides which door fits.

Can two single garage doors be replaced with one double door?

Yes, when the post comes out and one header spans the whole opening. That part is carpentry, and it has to be done and finished before the new door is measured. A garage door replacement for a widened wall is measured to the opening that exists after the framing, never to the two openings that were there before or to a plan of the new one.

The order is what trips people up. It is tempting to pick the door first, since that is the part you see from the street, and to treat the wall as a detail. But a door is built to a width and a height, and until the new header is in and the jambs are set, nobody knows what those two numbers are. A framer or builder does the wall. Our part is what goes into the finished opening: the door, its springs and tracks, and the opener.

What is the post between the two doors holding up?

Each single door has its own header, a beam across the top of the opening, and the post is where the inside ends of those two headers come to rest. On many garages the wall above sits on those headers, and on some the roof bears on them too. Whether roof load comes down through that post decides how big the one long header has to be, and that is a read a framer or builder makes on site.

From inside the garage you can see part of the story. Look up at the front wall and notice which way the rafters or trusses run, and whether anything rests on top of the wall right above the post. That tells you what kind of conversation to expect. It does not tell you what size of beam goes in, and nobody should guess at that from a photo.

Structural framing in a garage wall is the kind of work a city or county building office may want a permit for. Ask the office that covers your address before the wall gets opened, and let whoever does the framing handle what it asks for.

How wide is the opening once the post is gone, and what size door goes in?

Rarely a ready-made door size. Two single openings plus the post between them seldom add up to a standard double width, so the new opening is framed to the door width you choose, most often 16 or 18 feet. The height normally stays where the existing header line is.

That makes the width a decision to settle before any framing, since the framer needs a number to build to. Sixteen feet is the common two-car door. Eighteen gives two vehicles more room side by side and means a longer span for the header to carry, which goes back to the question of what the post was holding.

What does one wide door give up that two single doors had?

Mostly redundancy. With two doors, a broken spring or a dead opener on one still leaves the other bay working. One wide door hangs from one set of springs and rides on one opener, and it is a heavier door than either of the singles it replaces, so everything that lifts it is working harder.

There is a comfort cost on an attached garage, too. In a Howard County January, opening the full width to back one car out lets the air out of the whole garage, where a single door only opened the half you were using.

None of that rules a double out. It is easier to drive into, with nothing in the middle to clip on the way past, and from the street the front of the house reads as one door.

When should two old single doors be replaced with two new singles instead?

When opening the wall costs more than one wide door gives back. Two new single doors, ordered as a matched pair and hung in the same visit, keep the post and the headers exactly where they are. A few situations point that way more often than others:

• The post carries roof load, and a full-span header turns into a bigger job than the owner wants to take on.
• One bay is a workshop or storage and only the other one ever holds a car.
• The wall above the doors has windows or a gable vent that a longer header would run into.

In the workshop case, a door that opens a few times a month wears slowly, and the bay behind it keeps its own opening for the mower and the bench.

Both routes can be priced before anyone touches the wall. Single-car doors and what a new two-car door costs installed sit side by side on our cost page, and the framing quote is the other half of the double-door figure, coming from whoever would do the wall.

What happens to the two openers when two doors become one?

One opener goes up, centered on the new door, and the second one comes down. Every remote in the house and every car with a built-in button gets cleared and reprogrammed to the one remaining unit, and a wall keypad that used to run one door gets paired to the new one. The new door is heavier than either single, so the opener has to be sized for it. One of the old units may not be.

Centering matters for more than looks. An opener pulls from the middle of the door, and on a double that middle sits close to where the post used to stand, not where either old motor hung. The rail moves, the ceiling mount moves, and the outlet that fed one of the old units may not be anywhere near the new motor head. An outlet that has to move is easier to sort out before install day.

If neither old unit is a match for the wider door, a new garage door opener goes up in the same visit, with its travel and force set to the door it is lifting.