Some good paint options for the floor of a porch are Glidden Porch & Floor alkyd polyurethane gloss paint, Behr’s Porch & Patio Floor Paint and Sherwin-Williams’ Porch and Floor Enamel latex paint. Most exterior floor paints are specially formulated to withstand weathering, as well as excessive foot traffic.
Porch floor paints normally contain a high percentage of hard resins, which are incorporated into the paint to make it more durable. These resins fall under the category of enamels. Enamels are further categorized into acrylic latex and alkyd paints. Acrylic latex paints are water soluble, meaning they can be cleaned up with water. They are generally fast-drying and do not need to be diluted with paint thinner before they are applied.
Alkyd, or oil-based, paints are generally harder to work with because they dry slower and require noxious solvents to clean up. However, the oil-based qualities of the paints means that they are more resistant to weathering and therefore more durable.
It's best to choose an external porch floor paint that is slip-resistant, as well. Most external paints, whether they are alkyd or acrylic latex, have a semi-gloss or glossy finish. The finish adds durability to the paint; however, it tends to make surfaces slippery. Slip-resistant porch floor paints usually have gritty particles added to them, which add traction to the painted surface. However, these particles do wear away over time, which may lead to the porch having to be repainted.