The sticking sometimes occurs because:

• the screws, being too small or put in incorrectly, become overstressed and partly pull out of the timber.
  of a build-up of paint narrowing the necessary gap between the door and the frame (the jamb).
  moisture is getting into the door and making it swell.

Loose Screws
To establish if this is the problem open the door 100 mm and, using your arms, pull and push it towards the hinges. If there is movement then the screws are loose in either the door or the jamb. A telltale sign is cracked paint around the hinge.

Fix loose screws.

A Swelling Door
Keep an eye on whether the door sticks in humid weather or when the room is subjected to a lot of steam. If so, this means that moisture is getting into the timber through the joints or unpainted surfaces and causing it to swell. Not only does this cause sticking but long term it can lead to rotting. It may also cause the door to come apart because the glue gives way.

Wait for an extended period of dry weather or until you return from a holiday. If the door is no longer sticking, take it off and paint any areas that are bare or cracked.

Pay careful attention to the top and bottom of the door and any joints that show hairline cracks. By sealing the door fully you stop any moisture entering the timber, which should end the problem forever.

Removing Built-up Paint
This depends on the thickness of the build-up and the area of contact between the door and the jamb. If the whole edge of the door is sticking badly you may have to get in a carpenter to plane the door unless you have a plane and know how to use it. For small areas the following procedure is suitable.

You'll need
Screwdriver, cork block, pencil and rule; sandpaper (both rough and fine) and suitable paint.

Sanding procedure
Step 1
Check where it's sticking. When you are finished there should be an even 2mm gap to allow for clearance after repainting. Using a pencil, mark how much of the sticking area you need to sand off. Remove the door if it's binding on the hinge side or on the bottom, otherwise sand it in position.

Step 2
Using the rough sandpaper and the block, heavily sand the offending area. Make sure you keep the block flat and slightly angled towards the back of the door (the surface that fits in the rebate). Finish it off with the fine sandpaper. Then use the sandpaper to take the sharp edge off the corners. This is called arrissing and is done to stop splintering and to give the door a neat finish.

Step 3
Screw the door back on (if necessary) and check the gap for evenness and size. Sand further if required, prime and repaint the door.

Planing procedure
Step 1
If the whole edge is sticking and you have a plane, mark the 2-3 mm clearance, take the door out of the frame (either by taking out all the screws from the jamb or, if the hinge has a loose pin, driving the pin up with a hammer and a 75 mm nail).

Step 2
Next, set the plane iron. This involves firstly using the depth adjustment knob to wind the sharp blade (see Hand Tools for parts) out say 0.5 to 0.75 mm beyond the sole (bottom) of the plane. Next, hold the plane up towards the light and, using the lateral adjusting lever, make the blade parallel with the sole.

Step 3
Get a friend to hold the door or push it into the corner of a room. If you're planing on the lock side you will have to remove the lock.

When planing, start with the weight on the front of the plane. As you come off the timber, transfer the weight to the back. This will ensure the timber stays straight. If it's too hard to push, wind the blade back in. If lines appear on the timber, the blade is digging in on one side. Check it again for parallel.

If the wood is tearing you may be planing against the grain. Try planing from the opposite direction. If it tears from both directions, it has 'cranky' grain. Plane the way it tears the least.

Step 4
Make sure you slightly undercut the edge towards the back of the door. Arris the corners to get rid of sharp edges. Then screw the door back in the jamb, check the clearance, and repaint all bare surfaces.