The first question to be answered when planning to paint your garage door is this: wood or metal? This is crucial information, as it will guide the process from preparation through painting to the final clean-up. To get started, you will need a few items. They will be similar to either type of door, though there will be one or two things on the supply list that are different.
Take as much time as is needed to make sure that the surface of the door is clean and dry. For a wooden door on which the paint is cracked and peeling, you will need a wire brush and a scraper to get the surface as smooth as possible. If the door is aluminum you will need a firm scrubbing brush. This same type of brush can be used on wood after the scraping and wire brush step.
Protect Your Driveway
Make sure you have a drop cloth placed to protect your concrete or asphalt driveway from paint drops and spills. This will also help during clean-up, as it will catch paint chips during the preparation stage. For the wooden door, you will probably use a latex paint and primer, which makes for easier cleaning. For the metal door, you will probably use oil-based primer and paint, though you could also use an acrylic exterior paint. You should also have solvent or turpentine on hand for cleaning up after painting a metal door.
Before you paint a wooden door, be sure to make any repairs. In addition, you should caulk the cracks and edges to make sure you have a good surface for painting. This is a good time to go back and check for rough edges and places that still need to be scraped or wire-brushed (for wood) or cleaned and scrubbed (for metal). You may also want to use a commercial cleaner made specifically for the exterior surfaces of homes or other buildings.
A finished paint job is only as good as the surface it clings to. If there are rough surfaces, peeling paint, or other imperfections, your new paint will come off much more quickly. That’s why it is important to invest plenty of time in the scrubbing and wire-brush steps.
After you have thoroughly cleaned and washed the door, give the surface plenty of time to dry. Generally, a couple of hours is not enough. If the door is in the sun it could be dry in 24 hours. Be patient, as any moisture trapped under the new paint will keep the paint from sticking. It will lift off with just a slight touch, in many cases.
Use a quality primer when painting any older surface. Some primers can be used on any surface, though you should talk to your supplier to make sure that you are getting the product you need for your particular door. Always allow the primer coat to dry thoroughly before applying finish paint. You should definitely wait 24 hours. If the door gets moisture or dirt on it after the primer coat, clean the surface carefully and let it dry again. Plan to put on two finish coats, with a 24-hour drying period between applications.