How to fix a door that sticks due to humidity

Doors, like windows, stick for a number of reasons -- from poor construction to extreme humidity. In most cases, it's easy to unstick a stubborn door. To diagnose the problem, close the door, watching it carefully to locate the binding point.

If there's a gap between the door and the frame opposite the binding edge, the hinges probably need adjustment. If you can't see a gap anywhere between the door and the frame and you had to slam the door to close it, the wood has probably swollen from extreme humidity. If the hinges and the wood are both in good shape, the door frame itself may be out of alignment; check the frame with a carpenters' square. Once you know the problem, you are ready to find the best home improvement solution listed below.

To fix a door with poorly adjusted hinges, examine the hinges for loose screws, both on the door and on the frame. Securely tighten any loose screws. If a screw doesn't tighten, the screw hole has become enlarged. When the hole is only slightly enlarged, you may be able to correct the problem by replacing the screw with a longer one, but make sure the head is the same size.

Another option is to use a hollow fiber plug with the old screw. To do this, spread carpenters' glue on the outside of the plug, and insert the fiber plug into the enlarged screw hole. Then drive the screw into the hole. If the screw hole is badly enlarged, you can use wood toothpicks to fill it in. Loose hinge screws can also be tightened by filling the hole with wooden toothpicks dipped in glue and trimmed flush. Dip the toothpicks into carpenters' glue and insert them around the screw hole. Let the glue dry, then trim the toothpicks flush with the surface. When you drive the screw into the filled-in hole, it should hold securely.

If the screws are not loose, the hinges may have to be readjusted on the door frame. Close the door, watching to see where it sticks and where it gaps. If the door is tilted in the frame, it will stick at the top on one side and at the bottom on the other, and there will be a gap between the door and the frame opposite each binding point. If the door hinges need shimming, open the door as far as it will go. Push a wedge under it to hold it firmly.

At the hinge to be adjusted, loosen the screws from the hinge leaf on the door frame, but don't touch the screws in the door itself. Cut a piece of thin cardboard to the same size as the hinge leaf, and mark the location of the hinge screws on it. Cut horizontal slots in the shim to fit over the screws; slide the shim over the screws behind the loosened hinge leaf. Keeping the shim in place, tighten the screws to resecure the hinge. Remove the wedge holding the door and close the door. If the door still sticks, but not as much as it did before, add another shim under the hinge.

If the door sticks even after shimming, or if there is no gap anywhere around the frame, you'll have to remove some wood at the binding points. Use a block plane on the top or bottom of the door or a jack plane to work on the side. If the door sticks at the sides, try to plane only on the hinge side; the latch side is beveled slightly, and planing could damage the bevel. Use the plane carefully, removing only a little wood at a time. Keep your cuts even across the entire binding edge.

If the door sticks because the frame is out of alignment, there's not much you can do to fix it. At the binding point, set a piece of 2x4 flat against the frame, and give it several firm hammer blows. This may move the frame just enough to solve the problem. If this doesn't work, you'll have to adjust the hinges or plane the edges to allow for the unevenness of the frame. The door may end up slightly crooked, but it won't stick.

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The personality of an old door changes with the seasons. Pulled tight in winter, it's a stalwart guardian against chills and drafts. But by August, heat has driven moisture deep into the grain, and the once-yielding door has become swollen and stuck.

This Old House general contractor Tom Silva confronts a stubborn summertime door with a jack plane and a little restraint. "You want to take off the minimum amount of wood necessary because the door is going to shrink again in the winter," says Tom. "If you remove too much, it will sit loose in the opening." Follow along as Tom fixes a swelled door in his own home with just a few simple tools.

Step 1

Close Shave

Photo by Craig Raine

Tom's rule of thumb for keeping a door from sticking in the jamb is that the reveal—the space between the door and jamb—should be 1/8 to 3/16 inch wide, or about the thickness of a nickel.

Examining one sticky bedroom door in his house, Tom spends a little time getting a sense of its predicament. He opens and closes it to see where it catches, and he eyeballs the reveal. An uneven reveal may mean the hinges are loose or out of alignment. And, in fact, the screws holding the top hinge to the jamb have stripped their holes, causing the door to sag. But after fixing them, Tom finds that the door still sticks. Satisfied that humidity is the culprit, he pulls the hinge pins, lifts the door from the jamb, and gets ready to plane.

Photo by Craig Raine

To repair a stripped screw hole under the hinge leaf, Tom plugs the hole and gives the screw something new to bite into. He whittles a ¼-inch-wide, slightly tapered splinter out of a scrap of wood, then squeezes wood glue onto it and into the screw hole. He taps in the plug with his hammer, and glue oozes out of the hole. "You don't want to have a dry spot," Tom says, as he wipes away the excess, "or you won't get good adhesion." He snaps the protruding sliver flush with the hinge leaf. With the glue still wet, he refastens the hardware, cinching the screw tight.

Step 3

Deepen the Hinge Mortises

Photo by Craig Raine

After repairing the hinge, Tom sees that the door is still too big to close smoothly; he has no choice but to plane it to fit. To avoid disassembling the doorknob, he'll take the excess off the hinge side.

First he removes the hinges so he can chisel their mortises ⅛ inch deeper—the same amount he will plane from the door's edge. Holding a ¾-inch chisel vertically in the mortise, he hammers a dozen or so parallel ⅛-inch-deep cuts across the width of the mortise and one long cut against its inside edge. Then he leans his weight on the chisel—bevel side up—and rocks it gently back and forth, plowing out the chips of wood. He repeats the process on the other mortise.

Photo by Craig Raine

Tom knows that cutting through the layers of paint on this old door means he'll likely have to sharpen the plane's blade, called an iron, when the job is done. Luckily the finish is lead free, so slicing through it will not send hazardous particles flying. "If it were lead paint, I'd first want to use a chemical stripper," he says.

Curls of pine tumble to the floor as he runs the plane at a slight angle in long, smooth strokes along the length of the door. The plane iron leaves the edges sharp, so Tom rounds them slightly with some sandpaper to help them better accept paint.

Step 5

Paint the Raw Wood

Photo by Craig Raine

Before he goes any further, Tom slides each hinge leaf into its mortise to make sure the metal is flush with the door's edge. Then he pops the hinges back out and reaches for his paintbrush. "It's important to get the wood primed and painted as soon as possible," Tom says, to slow the creep of moisture. Otherwise, the door will swell again almost immediately, and "you'll be right back where you started." He brushes on a primer coat, then a finish coat, carefully blending the new paint into the old without dripping down the face of the door.

Photo by Craig Raine

Once the paint has dried, Tom re­attaches the hinge leaves. Then he hoists the door back into its opening, lining up the knuckles and dropping in the pins—first top, then bottom. Using the handle of his screwdriver, Tom taps each pin home, and then gives the door a test swing. It obligingly snaps shut, and the latch clicks cleanly into its strike plate. When Tom turns the doorknob and gives a gentle tug, it opens without resistance.