Whether it sticks a little or a lot, any door that challenges you to a wrestling match every time you try to open it needs to be dealt with. Prying with two hands while telling yourself it's good for your upper body strength is just enabling bad behavior on the part of the door. Humidity, sagging frames, and time are all contributors to this common problem. Here are some easy steps you can take to get that door back on its best behavior.
Check the hinge screws on the door first, then the hinge screws on the jamb (a.k.a. frame). If they are loose, the door will sag just enough to rub against the frame causing it to bind and stick when closed. If the hinge screws are loose, open the door as far as it can be opened, then tighten all of the screws.
Jane Tip: If you can't tighten the screws because the holes have become enlarged - remove the screws - then pack the enlarged holes with wooden toothpicks or match sticks that have been dipped in glue - so that together they form a flush surface. Before you replace the screws, be certain that the glue has set thoroughly. Tighten the screws securely.
If the door still sticks after the screws are tightened, then the problem may be corrected by adjusting one of the hinges. To determine which one, first determine where the door is sticking.
Close the door and slip a piece of paper between the door and the jamb - slide the paper around the edge. If it is sticking at the top corner, the bottom hinge needs adjustment; though if it binds near the bottom corner, the top hinge will need the adjustment. To do this, open the door to a 90-degree angle. Prop the door open, placing magazines and/or books under and around it to hold it in place. Next remove the screws that hold the hinge leaf in place. Cut a piece of cardboard the same size as the hinge leaf and place it behind the hinge leaf. Reposition the hinge leaf with the cardboard shim in place and replace and tighten the screws. Try the door again. If the problem is only partially corrected, try another thickness of cardboard behind the first shim.
Have your doors and jams been painted over? Try removing any excess paint on the edge of the door-and in the door jam if you have to. Use a medium fine grit sandpaper (150 grit) until it's smooth sailing.
Still stuck? Your doors may require a bit of planning to shave down the excess width with a plane. This is minor surgery, but it will require that you remove the door from its hinges (noting where the door binds) and carefully plane away just enough of the door's edge to alleviate the bind; typically you should plane in increments of no more than a 1/16 of an inch at a time. Plane with the grain of the wood and be careful: while most doors can accommodate some planing of their edges, there's no way to correct your mistakes if you take off too much. Re-hang the door and make sure it swings and closes freely.
If your doors are unfinished and tend to stick only in high humidity, consider sealing and/or painting them, so they'll change dimensions less with changes in the weather.
Sliding Doors: If it sticks in the track, open the door fully, thoroughly clean the track along the floor, and then lubricate the sides and the bottom of the track with a lubricating compound such as WD-40. Work the door back and forth several times.
Swinging Doors: Dust could be the culprit if a swinging door sticks. Look to see if the spring device in the floor is jammed. Unscrew the places under the bottom hinge and vacuum carefully. If you find any rust, scrape it off, and vacuum again. Then spray the spring and the pivot with a lubricating compound (WD-40). Re-screw the plates as above.
Life is too short to have daily struggles with your doors. Most problems can be cured quickly, without having to resort to shaving the door down or even removing it from its hinges. A few minutes of work now can get you out of your sticky situation-and let you save your strength training for the gym.