The short answer is: 100% acrylic paint.
In the old days they always built some sort of porch or awning
over the entrances, and the doors had some protection from
full sun and driving rain. We have better products today so
many builders skip those costly little details. I mention this
because it's something to keep in mind... if you ever do some
minor remodeling around the front door area, you might be able
to make a good-looking awning or porch roof that protects the
door, provides a bit of shelter from the rain (the primary
benefit) and adds some value to your house.
But the main issue is
providing protection for your steel door. The type of paint
you use depends on what type of paint is already on the door.
Most people paint their doors with latex paint, but some of us
do it the hard way and use oil-based paint, such as simple
spray cans (tricky because of the overspray) or a quart can of
oil-based paint like Rust-Oleum.
The problem is this: Latex
paint can go over oil-based paints or older latex paint, but
oil-based paint CANNOT go over latex paint, normally. Oil
paints will eventually crack like an alligator's skin when
applied over latex, because they expand and contract
differently with temperature changes.
So the answer is: You
can use latex paint with no worries. But which latex paint?
All exterior latex paints are meant to be placed in full sun,
and they will all fade over time with sun exposure. Some
colors fade worse than others. (I think I read that yellow
fades the worst, but my memory isn't so great anymore.) The
key is buying a high-quality acrylic latex house and trim
paint. Cheap paint isn't worth the savings! You'll only need a
quart to do a door. Even better... get a 100% acrylic paint.
It's my understanding that the acrylic polymer is one of the
most sunlight-resistant polymers available, so the more the
The other issue is gloss
level. Flat paint hides defects better than shinier paints,
but flat paints tend to form a chalky surface (which can leave
streaks). Shinier paints tend to be much easier to clean, and
since doors get touched all the time, flat paint will let the
fingerprints and grime be absorbed into the paint.
Personally, I use satin or
semi-gloss paints for doors and door trim.
Make sure you do the right
surface preparations, at least a good cleaning, rinsing,
drying, and scuff sanding. I prefer to paint the door on saw
horses... the paint is less likely to run or sag, and you can
get a heavier coating.
Bruce W. Maki, Editor.