Unless the old paint is in perfect condition, you should prime before painting. Primer blocks stains, mutes dark colors and helps new paint stick better. It also seals porous fillers so the topcoat looks smooth and even.
In all cases, doors need to be sealed on all four edges and the two faces to ensure that no moisture can penetrate to the door. Ensure that no bare timber is exposed. Even where there are cut-outs for locks, any bare timber should be primed. Remove hinges and paint behind hinges.
Before painting over a door, you need to prepare the surface to avoid any visible marks and make the paint last longer: sand it down, fill in any cracks with a filler, and clean the door with sugar soap,' says Valspar's Will Thompson.
“Painting a front door is best done with a brush. This is because most front doors have wood and/or glass panels and a roller would not be able to paint in the panels the same way that a brush would to give full coverage.”
Typically, two coats should suffice but you may prefer to use more. Drying times vary depending on a range of factors, including: the quality and type of paint or varnish you use; the environment you are painting in and the surface you are painting.
If you do not prime, the paint will rub right off when it is dry. If you are not sure what the old paint finish is, sand and prime to be on the safe side.
Although similar, both serve quite different functions. Primers act as a foundation for your paint to stick to while undercoats create a flat and level base for topcoats. One easy way to remember is if a surface is painted use an undercoat, if it's new, use a primer.
Unpainted wood and drywall can pose huge adherence problems for coatings without primer. With fresh drywall, the substrate actually absorbs a coating really well, like a sponge. However, because it absorbs so well, without a primer coat, you'll experience uneven coverage, especially along drywall seams.
Prep Work for Painting
Whether you paint your door in place or on sawhorses, you will want to remove all the hardware. Secondly, you'll want to clean the door with a wet rag, and then use a sander or sandpaper to remove any imperfections. Be sure to wipe away the dust from sanding before painting.
You also need to know what type of paint is already on your door. If it's latex, you can paint right over it. If it's oil-based, or if the door is brand new and unpainted, you'll need to do a coat of primer first so the paint has something to stick to.
As a general rule, says Mathew, a full litre of paint should be enough to apply three coats to a front door, including both sides, front and back, top, bottom and edges.
Note: Painting a door typically takes three to five hours, depending on the condition of the door and how fussy you are. But add in the drying time and it's a full-day project.
If you're painting a brand new door frame, you'll require a primer, undercoat and a top coat. For door frames that are already primed, you'll only need an undercoat and a topcoat. And, for door frames that need a fresh coat of paint, just the topcoat is required.
A front door could be painted in a satin or gloss finish – exterior paints are sold in both these finishes as well as flatter options. Gloss has more luster than satin paint and is generally more durable, and easier to clean, but satin can still be a great choice for a front door if you prefer less sheen.
Type of Paint to Use
Use interior acrylic-latex paint. Choose eggshell, satin, or semi-gloss sheens. Avoid using flat or matte paint on doors. Each door is 68 square feet, including front, back, and edges.
Painting a door is easy. It's actually easier to paint if you remove it. But if you're short on time or can't leave the door off the hinges during the painting process, here's how you can get the job done without having to remove the door.
Sand the Surface
Sand the existing paint by hand until the door feels even all over, starting with medium 120-grit sandpaper and working your way up to fine 220-grit sandpaper; if the door still feels rough, finish with 320-grit sandpaper. Wipe down the door with the tack cloth to remove paint dust and debris.
Sealing or sizing a piece of wood greatly reduces the chance of stains, warping and rotting wood from your paint. Yes, this can happen! You should apply two coats of sealer and let it dry thoroughly in-between each layer. Sealing also provides an easier surface to apply subsequent paint layers starting with a primer.