Q: The bifold doors in our laundry room have an uneven gap at the top that bothers us. The same imperfection is reversed at the bottom of the doors. The doors close evenly. I tried to move the right door bottom pivot to the right to lower the top of the door. But this is not possible, because then the right side of the door panel hits the wall and the door doesn't work. I suspect the wall or door frame is out of square. If I trim off the top of the panels, I fear the top panels will be unsightly. Is the solution to trim the right edge of the door?

Darnestown, Md.

A: Bifold doors come in pairs linked by hinges in the middle and have a track at the top that allows the doors to fold in a controlled way. They’re wonderful when there isn’t enough swing space for a regular door, but the moving parts can make adjusting them maddening. Luckily, no special tools are needed.

It’s important to understand how these doors work and what is — and is not — adjustable. Most adjustments involve positions of the pivot pins at the top and bottom near the side where the door meets the door frame. There is also a pin at the top on the section farthest from the door frame, but it just keeps that door sliding in the track at the top. This pin does not adjust.

The top pivot pin controls the pitch of the doors — the way they slant toward or away from the frame. On a pair of bifold doors, the top pins also control the gap between the doors. The bottom pivot pin has two adjustments. It slides right and left on a notched bracket, as you experienced. It also moves up and down thanks to an adjusting nut at the base of the pin.

Fiddling with the adjustments usually involves going back and forth a few times to see whether you can even out the gaps and still have a door that opens and closes smoothly. Before you start, check out your hunch that the doorway isn’t square. If it isn’t, no amount of fiddling with the standard adjustments will make the doors line up perfectly. You might be able to get them looking better than they do now, but knowing what the limits are will help you decide when “good enough” is the best you can do.

To test for a square doorway, you have a few options. With a bubble level, check whether the sides of the opening are plumb and whether the floor and top of the opening are level. Professionals use levels six feet long to check doorways, but if you only have a shorter one, tape it to a longer, straight board. Or test for square a different way: by measuring diagonally across the opening, from each top corner to the opposite bottom corner. You can do this with a tape measure, but if you don’t have a helper to hold one end steady, it might be easier to compare the diagonals using two sticks of wood that are each a little shorter than the diagonal distance. Grasp the sticks together, extend one tip into each corner and mark where the pieces overlap. However you determine the diagonal distances, if they aren’t equal, it’s a sure sign the opening is not square.

There’s no simple fix if the floor is out of level. If the top isn’t level, you might be able to shim the track to make it level. Shimming can also correct a doorway with sides that aren’t plumb, but you would need to adjust the doorway trim — a big job. First, see how much you can accomplish by adjusting the doors.

The picture you sent seems to show that both doors are uneven at the top, although gaps at the sides and center look parallel. The height adjustment on the bottom pivot pins might be the key to resolving your problem. Try raising the left door and lowering the right door, each by a little bit. Use your fingers, a flat screwdriver or a thin wrench to turn the nut at each bracket. Counterclockwise will probably raise a door; clockwise usually lowers it.

If adjusting the door heights isn’t enough, try adjusting the pitch of both doors so they slant a little more toward the left (counterclockwise to the current orientation). You can’t do that now because the left door is too close to the frame. But the gap on the right side of the doorway appears to be wider, so perhaps narrowing it a bit will give you enough wiggle room to even out the top edges through a pitch adjustment.

To move the right door closer to the frame, loosen the screw on the top pivot and slide it slightly toward the frame. Then tighten the screw. You will need to have someone lift up on the door while you make the adjustment, or you can first remove the door by lifting up on it until the bottom edge clears the lower pivot pin. After you move the top pin a little closer to the door frame, move the bottom of the door a little closer to the frame as well. Use a pry bar to lift the bottom edge while you scoot the pin one or more notches toward the door frame.

From the picture, it looks like you might want to position the right door slightly closer to the frame at the bottom than it is at the top. This would change the door’s pitch slightly and help even up the gap at the top. Then make the opposite pitch adjustment on the left door.

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