With proper maintenance a wood door can last as long as metal alternatives.
As with any other painting project prep work is 70% of the job. The actual painting of the door will not take long but you should follow a few basic steps to get the best finish.
First you must decide if you can remove the door. This is the best option because it will give you easy access to sand and paint. A door placed horizontally will also have less chance of paint runs. If you can not remove the door to paint it because of security or other reasons you should take care to let others know you are painting and that the paint will be wet for some time after you finish your work.
Interior doors are very easy to remove.
First open the door and remove the lock set and knob. To remove the knob you will need a philips head screw driver. First remove the plate covering the throw. Next on the locking side of the door remove the two long screws that hold the knobs in place. Remove one side of the knob and carefully inspect how the knob assembly is installed. Make notes or a diagram if needed. This is a relatively easy process but if you have never done this it is good to take notice.
Now with a chisel or large flat head screwdriver remove the pins that hold the hinges on.
Since the hinge side that is attached to the door may become lose if you remove the screws that hold the plate to the door it is not suggested that you remove this part instead use masking tape to protect it from sanding and painting.
Fix The Jam and Paint it First
Now that the door is removed you should inspect and repair the door jam first because it will need to be dry before you reinstall your painted door.
It is important to have the jam finished before the door so you can reinstall the door without problems.
If needed apply any wood filler to repair dents and glue, caulk and fasten any loose moldings.
Sand the jam for paint using a 220 sand paper and apply the thinest coat of paint that you can while providing full coverage.
If you have many layers of old paint on the door you may want to use a liquid stripper to remove the paint. Be careful when removing or sanding paint that you know to be older then 1975 because there is a good chance that it may contain lead.
Now that the door jam is done and drying lets get to work on the door.
Inspect the Door
The first thing you need to do is inspect the door for damage.
If it is an exterior door make sure you check the bottom for rot.
Check the hinges, If they are lose then you may need to remove the hinge bracket and repair the wood.
Small dents can be repaired with wood filler. Larger damage may require that you cut in a new piece of wood. Auto body filler is also a good product for repairing rot. Filler with Fiberglass fibers will add toughness. See our Porch Post Repair HowTo for how to use Body Filler to repair Wood.
Once you have repaired the structure of the door you can begin sanding.
Start with a 220 grit sand paper and feather all paint to an even surface.
Remove the dust with a dry towel, brush and vacuum cleaner.
Begin by painting the deepest portion of any raised panel inserts
Wipe away any drips then work on the center of the panels and the rails and styles
If you are painting many doors you may want to setup a production line
you can use a roller that has been washed to remove any lose fibers to apply paint to the door then follow up with a lightly loaded brush to give the wood a finished look.
It is important to cover all of the edges of the door with paint so that moisture won’t enter the door and cause it to warp and swell. High humidity in the summer months will cause doors to stick on their jams.
Now we haven’t covered painting around glass in doors.
If you have a door with glass you have 2 options either you can mask the glass off or you can paint and cleanup later.
New doors will come with a plastic protective covering on the glass that you can leave in place then remove after painting. But on older doors the easiest method is to use a small half inch brush to paint the mutton dividers and expect that a small amount will get on the glass. Allow the paint to dry and come back with a sharp razor blade held at an angle to the glass and scrape away the paint.
It is also good practice to have a little bit of paint cover the gap between the glass and the wood or caulking. This way you get a good seal. You don’t want too much paint on the glass about a 1/32 to 1/16 of an inch is more then enough.
To findout about paint choices check our other howtos
but it is best practice to paint your doors with a gloss paint to improve wear. And Exterior doors will require exterior paint.