Painting Flat Doors

Remove the door from its hinges and take off any hardware on the door, such as door knobs. Tape any screws to these items so they aren't lost or mismatched and take the door to a suitable work space, such as a garage.

Sand the door lightly to create a slightly rough surface that the paint can adhere to. This is especially important if the door has a coat of paint that is chipping off. Sand the chipped areas to remove any flaking paint.

Fill in any chips or cracks in the door using wood putty and caulking. On interior luan doors this is unlikely, but older doors may have cracks near the bottom if the door has been catching on carpeting over many years. Sand again before proceeding to the next step.

Prime the door with interior primer. Use a roller over the flat surface of the door. Paint one side and place your hands gently over the sides of the door and turn it around to paint the other side. Paint the sides and touch up any areas that may have been smudged when you turned the door over. Use a 2-inch flat paintbrush to paint the sides. Give the door time to dry.

Paint the door in the paint color you selected. Follow the same steps you used to prime the door -- first one side, then the other and then the sides. Use a roller for large flat parts and the paintbrush for the sides. Wait for the door to dry.

View the door in full daylight. Assess whether the door needs a second coat of paint. If so, repeat Step 5.

Reassemble the parts of the door and put the door back on its hinges.