Humid summer weather sometimes brings an irritating byproduct -- sticking doors. Moisture in the air is absorbed by the wood in some doors. The wood swells and the doors become difficult to open and close. Some doors stick even in dry winter weather, of course, so a balky door can be a year-round problem.
The first impulse of many do-it-yourselfers is to shave wood off the door edge with a plane or rasp, but this often isn't needed. Try these some simpler steps before removing any wood.
Check the hinges. Some doors are quite heavy; constant opening and closing puts strain on the hinges that can cause screws to work loose. Simply tightening the screws will cure many sticking doors. If the screws seem loose in their holes, however, the repair might be short-lived. For a more lasting repair, remove the old screws one by one and replace them with screws of the same diameter but one-half inch to one inch longer. Screws with oversized holes can also be tightened, at least temporarily, by inserting several pieces of toothpicks or some steel wool into the hole.
Check the finish. Lumps or thick drips in paint or varnish on the edges can make a door stick. Use a sharp wood chisel or knife to carefully peel off defects in the finish that could cause sticking. In many cases, this can be done without removing the finish to the bare wood. If the bottom edge of a door rubs the threshold or floor, try taping a piece of sandpaper (course side up) to the floor so the sticking point will pass over it. Open and close the door over the sandpaper several times to remove material from the door's bottom edge.
Try lubricant. Determine where the door is sticking and lubricate the area so it slides easier. Rubbing soap or wax on the sticking area will often help. Silicone spray lubricant, sold at most home centers and hardware stores, also can be used.
Try shims. A thin filler or shim behind one of the hinges will often free a door that sticks near the top or bottom of the latch side. The effect of shimming is to tilt the door slightly so it fits more squarely in its opening.